MR2 Roadster Owners Club

Yes that's right. I'm going to end it all :)

My bold claim is this;

"On the MR2, with MAF-based fueling strategy on stock ECU, the stock airbox is the best setup for performance and comfort." End of.

Evidence:
- Hurricane cone intake with EliseParts MAF behind battery; Fuel trims up to almost 35%, consistently across the mid to high load ranges. Inconsistent fuel trims lower down. Tried MAF cleans and ECU resets. Always went back to really bad fueling. 

When switching back to full OEM system, fuel trims went to between 0-4.7%, mostly 0. Nothing else changed but an ECU reset. Power is better, but first initial punch on the throttle is gone. 

- A while back I started a thread about testing different intake setups. It was never completed but one consistent theme across different cone setups was that fueling went all over the place in various degrees


Other mods:
A key thing to remember is that the MR2 uses electronic fuel injection and ignition.
You have a computer deciding how much fuel to inject and when to ignite it.
All a computer does is take inputs, do calculations and spit out outputs.

The MR2 uses a MAF-based fueling strategy. Meaning that the core input to drive all outputs, is the MAF sensor.
The MAF sensor is calibrated, from factory, specifically for the intake tract of the OEM system. What this means is that it is designed to put out a certain voltage for a certain airflow reading.
So the stock ECU, for example, knows that 2 volts = 50g/s of air, and that 5v is 100g/s (Not actual figures). 
If you change the intake tract or position of the MAF, you change the voltage the MAF puts out for the same airflow because of how air flows through a pipe. 
If you change pipe diameter, pipe shape, horizontal position of the MAF in the pipe, position of the MAF relative  to the filter and/or throttle body and position of MAF relative to a bend in the pipe, it changes the readings of the MAF.
Now, 2v might be 70g/s in real life, but the ECU will still translate it to 50g/s. So you have a discrepancy of 20g/s. That has massive repercussions on fueling. 

So what happens then? In this example, you are taking in more air than the ECU thinks is going in. You;'re putting in 70, but ECU things 50 is coming in. More oxygen is in the mix than the ECU thinks, therefore it is putting in less fuel than it needs. You're now running lean. That is caught by the o2 sensors, which then tell the ECU to add fuel because something is wrong.
Unfortunately, o2 sensors are slow. So you're forever a step behind. Your engine never runs at peak performance. Even after long term fuel trims are stored to try to correct for your bad MAF setup.
If the concentration of oxygen in air never changed, your long term fuel trims would learn and you'd be fine. But pressure, temperature, humidity etc all play a role in oxygen content. Even as you drive, your engine gets hotter and heats the intake. Therefore, day to day, your long-term fuel trims are always going to be off. Your ECU is forever trying to fix your fueling. Unsuccessfully.

So what can you do for more power? Exhaust mods. That's why they're so successful in an MR2 versus intake mods.
If you improve the ability for your engine to push gasses out but also to pull fresh air in (different topic), then you're increasing the pumping efficiency of your engine while never touching its ability to read the airflow correctly.


But I want intake mods:
Well then there are 3 ways to go.
1) Live with the fact that your fueling is off by miles, you're causing excessive wear, and likely passing MOT is an issue. Make that ECU work overtime and bear in mind that your o2 sensors are your lifeline, so monitor them and make sure they're always in tip-top shape, replace them every few years. And enjoy the roar and direct response of a cone intake

2) Install a piggyback ECU with the sole purpose being to adjust the airflow, but get it calibrated. This means that you have to put the stock system on, monitor MAF voltage across various load ranges and then dyno it again with the new intake and adjust the MAF signal until it matches (as much as possible) the stock readings.

3) Install a standalone ECU and convert the system to a speed-density fueling strategy. This no longer uses the MAF, but uses manifold pressure (MAP) instead. THis means that you can do whatever the hell you want to your intake. But expensive.

Middle ground:
- A "sports" filter, such as the TRD.
- the TRD intake trumpet
- Mark III intake elbow.
These improve the breathing capability of the car while not messing with the MAF's readings at all

You're such a geek. But I for one am glad you're "our" geek and worth way more than last weekend's token donation to the club for sorting my idle out.

Quote from: Call the midlife! on August 14, 2019, 10:58You're such a geek. But I for one am glad you're "our" geek and worth way more than last weekend's token donation to the club for sorting my idle out.

There's a compliment in there somewhere... hahaha  Thanks :)  Happy to be the club geek.


In non-geek I suppose it's:
If you want roar and shit fueling, change your intake. If you want the best performance on stock ecu, keep the stock intake.
If you're going to change the ECU, the world is your oyster.

Quote from: Call the midlife! on August 14, 2019, 10:58You're such a geek. But I for one am glad you're "our" geek and worth way more than last weekend's token donation to the club for sorting my idle out.

Do tell..... :)

Since you're in full-flow Patrick, - where does the maf -riser fit into this thinking?

I don't think it does ;)

Quote from: Gaz mr-s on August 14, 2019, 11:47Since you're in full-flow Patrick, - where does the maf -riser fit into this thinking?

The MAF riser fits Shnazzles explanation with a twist as it is not about increasing the airflow.
By changing the MAF position, the reading is erroneous just as Shnazzle writes The ECU adjusts to the perceived engine load by advancing the ingnition. Thát, advancing the ignition is the goal.

Yup. It's fakery. 
But unfortunately you're changing more than just maf height. You're also increasing injector size and removing the intake vanes. 
Cap Weir did a LOT of work to get this to work as well as possible with the stock ECU, but in the end there are going to be holes.
That's why we've had people with problems with running, starting, fueling, codes, etc. It'll work within certain situations and parameters, but the boundaries are much narrower than without it.

Quote from: shnazzle on August 14, 2019, 09:47Middle ground:
- A "sports" filter, such as the TRD.
- the TRD intake trumpet
- Mark III intake elbow.
These improve the breathing capability of the car while not messing with the MAF's readings at all

Also:

- the for free trumpet mod/air duct delete, using the OEM elbow ;-)

I ran with the filter behind the battery, stock MAF tube (retaining the OEM velocity stack) with the short 45 degree coupler to the throttle body, no issues with fueling on the stock ECU on mine.

With noting however that the stock sized paper air filter is ok for the 2zz which runs around 50bhp more so the stock setup should be able to outflow whatever the 1zz engine makes.

Quote from: m1tch on August 14, 2019, 16:13I ran with the filter behind the battery, stock MAF tube (retaining the OEM velocity stack) with the short 45 degree coupler to the throttle body, no issues with fueling on the stock ECU on mine.

With noting however that the stock sized paper air filter is ok for the 2zz which runs around 50bhp more so the stock setup should be able to outflow whatever the 1zz engine makes.

It was definitely better with the stock MAF housing. Won't argue that. Trims were around 10-15% tops. THe EliseParts maf, in my opinion,isn't suitable for 1zz or 2zz stock.


As you say though, the stock setup is good enough for 2zz (although it does have a wider throttle body), so to assume it's not good enough for 1zz is a bit silly :)

I think most of the time people do the intake mods without any means or experience to quantify the effectiveness, other than liking the extra growl and perceived "liveliness" post mod.
If you're happy with the results and don't bother checking the trims etc then you're just going to press the loud pedal and assume everything is ticketyboo!
Personally I've got all the gear and no idea, which is why I end up sat in a carpark on a drive out with Shnazzle tutting at my cluttered desktop and working his black arts on my ECU.

Quote from: shnazzle on August 14, 2019, 13:50Yup. It's fakery.
But unfortunately you're changing more than just maf height. You're also increasing injector size and removing the intake vanes.
Cap Weir did a LOT of work to get this to work as well as possible with the stock ECU, but in the end there are going to be holes.
That's why we've had people with problems with running, starting, fueling, codes, etc. It'll work within certain situations and parameters, but the boundaries are much narrower than without it.

We have been running the MAF mod (riser) on 2 different MR2's with no issues.  Both have stock intake air box systems and the cheap clone headers with stock cat and muffler.  The power change is noticeable.  A friend ran the the same setup with and without the mod on the same dyno, and the riser (and other related changes) added almost 5 HP, which was a bit unexpected.  On our cars, fuel mileage improved 1-2 mpg.

The only negative is a somewhat harsh fuel cut on overrun at about 3,000 rpm, but that doesn't happen all the time.

I suspect some people have issues because of air leaks with homemade risers.  One we have was made by Cap Weir, and the other was manufactured by Corky when he was making them and they both use o-rings to seal.  We did have issues when one came slightly loose and we had a very small air leak, but that was easy to fix.  The height also seems very critical.

Quote from: Beachbum957 on August 14, 2019, 18:33

Quote from: shnazzle on August 14, 2019, 13:50Yup. It's fakery.
But unfortunately you're changing more than just maf height. You're also increasing injector size and removing the intake vanes.
Cap Weir did a LOT of work to get this to work as well as possible with the stock ECU, but in the end there are going to be holes.
That's why we've had people with problems with running, starting, fueling, codes, etc. It'll work within certain situations and parameters, but the boundaries are much narrower than without it.

We have been running the MAF mod (riser) on 2 different MR2's with no issues.  Both have stock intake air box systems and the cheap clone headers with stock cat and muffler.  The power change is noticeable.  A friend ran the the same setup with and without the mod on the same dyno, and the riser (and other related changes) added almost 5 HP, which was a bit unexpected.  On our cars, fuel mileage improved 1-2 mpg.

The only negative is a somewhat harsh fuel cut on overrun at about 3,000 rpm, but that doesn't happen all the time.

I suspect some people have issues because of air leaks with homemade risers.  One we have was made by Cap Weir, and the other was manufactured by Corky when he was making them and they both use o-rings to seal.  We did have issues when one came slightly loose and we had a very small air leak, but that was easy to fix.  The height also seems very critical.

More likely is that people run different fuels, live in different environments, injectors are of varying performance, burning oil or not, etc etc.

The DIY spacers certainly don't help, or running intakes that differ from Cap's existing standards. 
Issues on overrun or tip-in makes sense. The poor car still thinks you're on stock injectors. 

It's a mod that undeniably works, and has pleased the masses, but the amount of issues encountered isn't a coincidence. As I said, the margins are much narrower. If you're in the margins you're all good. 5hp across two dyno runs is neither here nor there though but the noticeable pickup is what gives the thrill.
Did the same with my piggyback. I do miss that "urgency". Not enough to go back to the piggyback though

I'm interested in this thread, as I have recently suffered from a massive bout of overfuelling in my 2ZZ car - albeit this is the only time in 6 or so years I have ever had this issue (including many, many track days).

I am running with a MWR MAF adapter, and a cone filter behind the battery.

I wonder if the stock 1ZZ setup would work well on a 2ZZ?

Quote from: Alex Knight on August 15, 2019, 11:52I'm interested in this thread, as I have recently suffered from a massive bout of overfuelling in my 2ZZ car - albeit this is the only time in 6 or so years I have ever had this issue (including many, many track days).

I am running with a MWR MAF adapter, and a cone filter behind the battery.

I wonder if the stock 1ZZ setup would work well on a 2ZZ?

I've seen Rogue builds with the stock 1zz setup,so I imagine it's definitely a good starting point. For what it costs..

Get a stock kit from a breaker, plop a performance panel in for good measure and see how you go. The 2zz flows a LOT more air, but it uses the same filter panels as 1zz.
The more damaging approach is to cut the stock airbox up and take the MAF adapter from that and fit a cone to it.

Quote from: shnazzle on August 15, 2019, 12:01

Quote from: Alex Knight on August 15, 2019, 11:52I'm interested in this thread, as I have recently suffered from a massive bout of overfuelling in my 2ZZ car - albeit this is the only time in 6 or so years I have ever had this issue (including many, many track days).

I am running with a MWR MAF adapter, and a cone filter behind the battery.

I wonder if the stock 1ZZ setup would work well on a 2ZZ?

I've seen Rogue builds with the stock 1zz setup,so I imagine it's definitely a good starting point. For what it costs..

Get a stock kit from a breaker, plop a performance panel in for good measure and see how you go. The 2zz flows a LOT more air, but it uses the same filter panels as 1zz.
The more damaging approach is to cut the stock airbox up and take the MAF adapter from that and fit a cone to it.

Just thinking about my history with the standard 1zz setup and the stage 2 cams, I wonder if it would cause similar problems with the 2zz intake?

I know k&n filters are like snake oil to many, but the panel filter is far superior to a paper one. Not to mention it lasts forever.

Quote from: The Other Stu on August 15, 2019, 23:16I know k&n filters are like snake oil to many, but the panel filter is far superior to a paper one. Not to mention it lasts forever.

How often do people generally clean/re-oil their K&N panel? The instructions say every 50k miles which seems pretty insane. Anything to be gained from doing them more regularly or is it just time/expense wasted?

Quote from: The Other Stu on August 15, 2019, 23:16I know k&n filters are like snake oil to many, but the panel filter is far superior to a paper one.

Unfortunately there is no free ticket here either.
K&N does flow more air, it also passes more particles. Pick your choice.
This applies to basically all ´sports´ filters; flowing more at the price of filtering less particles out.
Just about the only solution flowing more ánd retaining a good deal of particles is the centrifugal filter; an open cell foam element with a véry thin coating of sticky fluid. Those too have a price; they need very frequent cleaning and wear from that. Again, pick your choice.

Quote from: househead on August 16, 2019, 00:37How often do people generally clean/re-oil their K&N panel? The instructions say every 50k miles which seems pretty insane. Anything to be gained from doing them more regularly or is it just time/expense wasted?

The instructions are a selling point and should not be taken on face value. Although the filter does not clog as quickly as a paper filter because it ´filter´ using static attraction, the ´force field´ of that deminishes with the square root of the distance to the metal = the layer of dirt.
After cleaning the static enhancing fluid must be applied to have the original effect. Just about áll users apply waywáy too much with subsequently gets sucked in and sticks to the MAF wire p.e.

The static thing does work, just not wonders and it has it´s specific limits; filtering less effectively and needing cleaning regularly depending on the conditions: On our two vintage ralley cars 2500 kms was quite enough; about double the paper filter ánd they filtered not as effectively but that was an accepted price. Well ´accepted´; I would have used centrifugal foam moto-X material if I could have made it fit for the carburettors. The same applies to my MR bút I am still chasing that; hoping to get TwinAir foam in a tray.

...and like it often goes a piece of double Twin Air foam is coming my way; enough for three elements.
Cost 37 €uros and an old filter.

(https://i.ebayimg.com/images/g/SRIAAOSwWnpdGzri/s-l1600.jpg)

So that will be an OEM intake with elbow mod/ duct delete and a réally proper filter element.

Quote from: Alex Knight on August 15, 2019, 11:52I'm interested in this thread, as I have recently suffered from a massive bout of overfuelling in my 2ZZ car - albeit this is the only time in 6 or so years I have ever had this issue (including many, many track days).

I am running with a MWR MAF adapter, and a cone filter behind the battery.

I wonder if the stock 1ZZ setup would work well on a 2ZZ?

It won't. It will run but it will over report the fuel trims but it will do something much worse, it will choke the 2ZZ. 
The 1ZZ intake uses a different vane arrangement and it is calculated for the 1ZZ ECU. Some people have done this and were wondering why they lost nearly 30hp.

The MWR intake does just the opposite like most aftermarket intakes  which is it will under report and add fuel. This will decrease the part throttle response.
 The only right intakes is the Cobb intake for the WRX or the stock 2zz intake. 

 All of these intake modifications can work with stock ECU but it wasn't meant for that. The increase or decrease in fuel trims are a way of compensating for dirty air filtration, engine wear and sensors that drift out of calibration as the car gets older.  The ECU will just chug along with a decrease in fuel efficiency and power but the most important thing they make sure of is that the car is emissions compliant.
   

 On the flip side of things you can trick the computer into making more power for you by messing  with the intake to some extent. This is very similar to using a piggy back. In order to do this the intake needs to be flow tested on a bench and tested against the ECU. Cap did this and thats why it works however its not a one size fits all as you can have an issue if the engine is badly worn, damaged or possibly in a different altitude from where the tests were conducted.   

I wonder what Rogue have done to the 1zz intake system then to make it work on 2zz. They must have rebuilt the MAF adapter to be chopped from the 2zz or done something trickier. 
When I looked in the bay it definitely looked stock to me. But I didn't have a close look. 
What I don't understand is sometimes they do that, sometimes they provide cones with another setup.

Quote from: Dev on August 16, 2019, 15:04or possibly in a different altitude from where the tests were conducted.   

Good point.
I live at 800 meters and an average day sees 0 to 1200 metres.

Quote from: Petrus on August 16, 2019, 09:03...and like it often goes a piece of double Twin Air foam is coming my way; enough for three elements.
Cost 37 €uros and an old filter.

(https://i.ebayimg.com/images/g/SRIAAOSwWnpdGzri/s-l1600.jpg)

So that will be an OEM intake with elbow mod/ duct delete and a réally proper filter element.

Interested. What makes this material so much more superior to readily available filters? Or is the idea that this TwinAir stuff is throw-away?

This is getting to be an awful lot of final words'. :o

Quote from: Carolyn on August 16, 2019, 16:17This is getting to be an awful lot of final words'. :o

Haha. Well the final words remain and there hasn't been any challenges :) 

The rest is just extra fluff

Quote from: shnazzle on August 16, 2019, 15:36I wonder what Rogue have done to the 1zz intake system then to make it work on 2zz. They must have rebuilt the MAF adapter to be chopped from the 2zz or done something trickier.
When I looked in the bay it definitely looked stock to me. But I didn't have a close look.
What I don't understand is sometimes they do that, sometimes they provide cones with another setup.

The easiest way to know is if the fuel trims read negative at idle and if at part throttle the fuel trims are in the range of less than +5.  If they read closer to  +10 LTFT then its probably correct. 
 This is assuming that other things are correct. If there is any exhaust restrictions it can though off the fuel trims. 

Negative fuel trim is usually pointing to a problem but not always if its on the boarder there are some rare situations where it is normal but when I see them I know something isn't optimal.

True positive fuel trims are good. It can mean that you have a less restrictive intake and exhaust which the car can now take advantage of your modifications but upto a certain point where it runs out of allowable fuel trims and then throws a CEL.

The intakes on these cars is generally not the choke point but we downgrade them when we think we are adding a modifications that we believe are a benefit because of false marketing. The major choke point is the downpipe and that is where you will get real gains for most cars but somehow it is the most overlooked modification. 


 

Quote from: Petrus on August 16, 2019, 15:58

Quote from: Dev on August 16, 2019, 15:04or possibly in a different altitude from where the tests were conducted.   

Good point.
I live at 800 meters and an average day sees 0 to 1200 metres.

There have been known issues with adopting or trading tunes for stand alone ECUs but this is when elevations are extreme. The ECU like our is sophisticated enough to adjust for the barometric pressure which is read by the MAF sensor.  However when you do something different to fool the ECU for more power it can then misbehave.  These ECUs are sophisticated but they are far from perfect especially when you add modifications to them.   

Quote from: shnazzle on August 16, 2019, 16:03Interested. What makes this material so much more superior to readily available filters? Or is the idea that this TwinAir stuff is throw-away?

It is not a filter in the traditional sense of sieving out particles larger than the holes.
Thís foam is designed to be a labyrith forcing the air to change direction, causing particles to sling to the outside. The surface being thinly coated with very sticky fluid, the particle get caught.
As such it is a centrifugal filter, not a seive like paper and other foam inserts.
The holes can be a lot larger. More so because the foam is two stage; first more course and then finer.
This prevents the easiest caught heavier/larger particles from clogging the finer layer.

This type of filter has almost five decennia* of prooven history in motorcross but has not flown widely outside of that.
The reason is that it is not maintenance free and that maintenance rather involved. You need to wash the filter fairly regularly and applying the fluid is a sticky affair costing time and effort. That simply is too expensive for commuter cars et al.
Also the filter needs to dry overnight at least.
Light coating only and letting it dry are paramount!! in preventing the fluid from being sucke through. Hence I always had two elements so I could swap out and clean the dirty one at leisure, store it in a sealed plastic bag ready for re-use.

How often it needs cleaning depends ofcourse. I live in dusty country and would wash it out between 5K and 10K kms. In say the Netherlands make that 10K plus.
The cleaning/coating causes mechanical wear on the material but it still has the life time of a  few paper filter elements.

As I wrote, it is the only ´exception´ to the rule of better flow = less filtering. Between brackets because it does not síeve.

* the basic idea goes back wáy futher still to the simple metal mesh carburettor inlet coverings. Those were supposed to be lightly oiled with heavy oil diluted with petrol.
They were intended to be washed out weekly, even daily but because the principle was not understood by the users, nobody maintained them correctly and in practice were hardly better than nothing so they went the way of the dino.

Quote from: Dev on August 16, 2019, 17:40The ECU like our is sophisticated enough to adjust for the barometric pressure which is read by the MAF sensor.   

Same thing temperature and relative humidity.
At this very moment ambient air is 43 degrees centigrade and humidity mid 20%.
Together with the altitude, this seriously reduces power output but the mixture is ok.

I have driven the car to 2000 metres on a hot day and noticed no change in idle from a near freezing rainy day at the coast so I´d say that the parameters are quite widely programmed.

Quote from: Petrus on August 16, 2019, 18:01

Quote from: Dev on August 16, 2019, 17:40The ECU like our is sophisticated enough to adjust for the barometric pressure which is read by the MAF sensor.   

Same thing temperature and relative humidity.
At this very moment ambient air is 43 degrees centigrade and humidity mid 20%.
Together with the altitude, this seriously reduces power output but the mixture is ok.

I have driven the car to 2000 metres on a hot day and noticed no change in idle from a near freezing rainy day at the coast so I´d say that the parameters are quite widely programmed.

Very true. The problem often times comes from standalone ECUs that are not as sophisticated as the stock ECU to make those changes effectively. It also comes from modifications that are not adapted well that fools the ECU taking it to its limits.

 One thing to be pointed out. A under or over reporting maf will not be the primarily reason for the power loss in regard to fueling. It is the calculations of the ignition timing that is key here. The 02 sensors rule the fueling ultimately to keep the cars fueling  within specifications. It will not run rich or leaner otherwise it would greatly effect emissions. This is a strategy that is programed from the manufacture as the car ages and deteriorates.

 The problem with these intake is, ECU will not take advantage of the timing that is read by the MAF and calculated by the ECU and it will be most felt during part throttle. A good part throttle  response is what gives you  drivability which is what is missing from aftermarket intakes. 

Will you boys, please, stop showing off how clever you are?

All of this adds up to.  'Leave the bugger alone' doesn't it? 

And before you answer.  Yes it does. ;)

One side note; even further aside.
Vroegâh, in the previous century, when we were still faffing about with jets, needle hight, slide cut out, venturi shap/side et al, a good table for relative air density and humidity was crucial hence also a meteo set  :o

Back on subject; yes Carolyn, succinctly put!

Quote from: Carolyn on August 16, 2019, 18:26Will you boys, please, stop showing off how clever you are?

All of this adds up to.  'Leave the bugger alone' doesn't it? 

And before you answer.  Yes it does. ;)

Hahahaha ha

Brilliant!

Quote from: Carolyn on August 16, 2019, 18:26Will you boys, please, stop showing off how clever you are?

All of this adds up to.  'Leave the bugger alone' doesn't it? 

And before you answer.  Yes it does. ;)

Im certainly not. I don't see why it really matters if there is a discussion. I didn't know it was perceived as showing off as I take exception to that kind of ridicule when Im just trying to be helpful, not clever.

Quote from: Dev on August 16, 2019, 18:57

Quote from: Carolyn on August 16, 2019, 18:26Will you boys, please, stop showing off how clever you are?

All of this adds up to.  'Leave the bugger alone' doesn't it? 

And before you answer.  Yes it does. ;)

Im certainly not. I don't see why it really matters if there is a discussion. I didn't know it was perceived as showing off as I take exception to that kind of ridicule when Im just trying to be helpful, not clever.

It's all in jest Dev. 

But that was the point of this particular thread, and there isn't actually much (if any) argument against my statement. 
Having said that, obviously I won't back out of a nice juicy discussion about fuel trims :) 
It'll be on my grave stone: "His fuel trims exceeded maximum tolerance "

A quick question though, with a piggyback is it still best to use the OEM intake or change for an aftermarket one?

Quote from: Gatouzze on August 16, 2019, 21:05A quick question though, with a piggyback is it still best to use the OEM intake or change for an aftermarket one?

It's kind of the other way round, if you're not changing the intake you've little need for a piggyback. But if you're using a high end one that allows you to tailor your timing for instance then you've got scope to change your intake as well.

Quote from: Gatouzze on August 16, 2019, 21:05A quick question though, with a piggyback is it still best to use the OEM intake or change for an aftermarket one?

Aftermarket for the 2ZZ however it is a loaded question. Some found that the vanes seemed to make tuning a bit better  because it was easier for the map to be scaled correctly.  Therefore some actually bought the larger Cobb intake and was able to have the best of both worlds with the 2ZZ that can benefit from a larger intake. 

This tells me that the MAF was calibrated with the tube to very tight tolerances. 

If you are interested I can try and find you a used Cobb intake and send that over to you for testing.

Quote from: Dev on August 16, 2019, 21:13Aftermarket for the 2ZZ however it is a loaded question. Some found that the vanes seemed to make tuning a bit better  because it was easier for it to be scaled correctly.  Therefore some actually bought the larger Cobb intake and was able to have the best of both worlds with the 2ZZ that can benefit from a larger intake. 

This tells me that the MAF was calibrated with the tube to very tight tolerances. 

If you are interested I can try and find you a used Cobb intake and send that over to you for testing.

I very appreciate the offer but I am running a 1ZZ but I'm sure someone running a 2ZZ could be interested! ;)

Quote from: Gatouzze on August 16, 2019, 21:18

Quote from: Dev on August 16, 2019, 21:13Aftermarket for the 2ZZ however it is a loaded question. Some found that the vanes seemed to make tuning a bit better  because it was easier for it to be scaled correctly.  Therefore some actually bought the larger Cobb intake and was able to have the best of both worlds with the 2ZZ that can benefit from a larger intake. 

This tells me that the MAF was calibrated with the tube to very tight tolerances. 

If you are interested I can try and find you a used Cobb intake and send that over to you for testing.

I very appreciate the offer but I am running a 1ZZ but I'm sure someone running a 2ZZ could be interested! ;)

Sorry about that, I had my wires crossed. 
I meant that for Shnazzle

Quote from: Dev on August 16, 2019, 15:04

Quote from: Alex Knight on August 15, 2019, 11:52I'm interested in this thread, as I have recently suffered from a massive bout of overfuelling in my 2ZZ car - albeit this is the only time in 6 or so years I have ever had this issue (including many, many track days).

I am running with a MWR MAF adapter, and a cone filter behind the battery.

I wonder if the stock 1ZZ setup would work well on a 2ZZ?

It won't. It will run but it will over report the fuel trims but it will do something much worse, it will choke the 2ZZ. 
The 1ZZ intake uses a different vane arrangement and it is calculated for the 1ZZ ECU. Some people have done this and were wondering why they lost nearly 30hp.

The MWR intake does just the opposite like most aftermarket intakes  which is it will under report and add fuel. This will decrease the part throttle response.
 The only right intakes is the Cobb intake for the WRX or the stock 2zz intake. 

 All of these intake modifications can work with stock ECU but it wasn't meant for that. The increase or decrease in fuel trims are a way of compensating for dirty air filtration, engine wear and sensors that drift out of calibration as the car gets older.  The ECU will just chug along with a decrease in fuel efficiency and power but the most important thing they make sure of is that the car is emissions compliant.
   

 On the flip side of things you can trick the computer into making more power for you by messing  with the intake to some extent. This is very similar to using a piggy back. In order to do this the intake needs to be flow tested on a bench and tested against the ECU. Cap did this and thats why it works however its not a one size fits all as you can have an issue if the engine is badly worn, damaged or possibly in a different altitude from where the tests were conducted.   

Very interesting stuff - fully appreciate you sharing your knowledge. Guess I'll stick to the cone behind the battery!

(https://myalbum.com/photo/gSmEQurn8HXv/1k0.jpg)

(https://myalbum.com/photo/pWV5mmtWHQpj/1k0.jpg)

To make the filter of champions:
- get a sheet of twin layer from Twin Air
- find (or diy) an old filter element with gauze insert

Cut the filter foam to size of the outside!! of the rubber circumferance.
Soak the foam in filter fluid.
Massage so all the foam is coated.
Squeeze the foam so excess fluid drips out.
Let it dry for at least 4 hours.
Again massage, now with paper towel.
Foam ready to be fitted!

Lay the foam with the orange side up in the filter box.
Put the gauze on top.
Now VERY CAREFULLY fit the filter box cover: Take care not to move the faom and gauze!
The goal is to have the rubber edge of the old filter element hold the foam on the surface edge of the filter box. The lid clamps it all down; the foam will compress and thus seal.

As explained earlier, this foam is very free flowing and the sticky surface will capture the particles efficiently.
It was designed for high revving small capacity two-stroke engines with minute filter housings and currently keeps the high powered four stroke off road bikes free yet clean breathing.

It is a bit of a faff but it works and imo the only filter material that flows ánd cleans air.

Link to filter material?

Quote from: shnazzle on August 28, 2019, 11:39Link to filter material?

https://www.twinair.com/air-fuel-oil-filtration-products.php


Part numbers of the sheets;

160002 Single Stage Foam (600X300X10mm, Orange)

160003 Dual Stage Foam (600X300X15mm, Orange/White)

160003B Single Stage Foam (600X300X20mm, Orange)

160004 Triple Stage Foam (600X300X18,5mm, Orange/White/Black)

You will need to order from a UK based dealer.
 

Patrick same as me, struggling to navigate the site...???.....I've since input the code for the filter element you pictured Petrus, & it still didn't want to play....  ::) 

However googling it gives this....
https://www.ebay.co.uk/itm/Twin-Air-Dual-Stage-Air-Filter-Foam-Sheet-160003-600x300x15mm-/173972891106?_trksid=p2349526.m4383.l4275.c1

I considered the Twinair to refresh the foam in the HKS Mushroom as I'm familiar with their moto filters but also got bored trying to find it on their website 😂

Now to source a housing for it.... :-\

Find a dealer through the side and order de part number from thém. Worked for me ;-)

I want to quickly resurrect this intake discussion as it was going to be the next mod to my roadster, but after reading these posts I'm undecided and have some questions.

I really want to go with a behind the battery cone filter primarily for the acoustics and a tad better throttle response. I accept I might be losing a couple of hp or low end torque in doing so.

So ripping the stock intake pipe out of the airbox and retaining the all important vanes seems the best way to go.

It's suggested in these posts that still causes a positive shift in ST/FT's
Is this proven or an estimate?? Many who have fitted this set up comment that it runs well and seems to make no difference with the butt dyno. Was the actual before and after deltas in the trims actually recorded?

If there is a positive shift in FT's then can anything further be done to keep them to a minimum?

I see some people fit the cone straight on to the MAF pipe - would a 3" length silicone pipe between the MAF and cone help out further?

In the concept of the MAF mod, raising it's position in the pipe causes FT's to go negative. Can this idea be used to offset any increases?

If I do go ahead with this I will probably use a 70mm Apexi cone. Is this weight of all of this going  to be ok suspended from the throttle body or do I need to think about fabricating a support bracket?

Sadly, I cannot answer your questions and I know it's not want you want to hear.

But, when it comes to the intake on a stock setup. Stock is best.

I'm sure the @shnazzle will be along shortly and dispense the wisdom you seek.

If you are happy sacrificing some performance for noise. Go for it.

Hello and welcome by the way.

Yes. If you're going to do it, the way to do it is to either reproduce or use the stock maf adapter with vanes, in a pipe of the same diameter as stock. So basically you're shortening the tract and adding a less restrictive filter.

People never complain because it does run "well".
The ecu compensates best it can and often very successfully. At the cost of performance.

IF the maf is reading correctly. Big IF. Then a positive fuel trim after installation of the air filter could mean that the car is getting more air in, therefore it's adding more fuel. A good thing.
But, you'll have to know exactly how it was fueling before to know for sure if it was the intake and not an o2 sensor fading or something.

The measurements of changes in fuel trim are proven. Quite a few times.

Support bracket would be best but depends on how much pipework. I had a very short pipe and filter suspended by TB and the other end held up by the pipe that went to the side intake. Never budged

The best intake set up for a stock ECM is going to be one which advances the timing the most, has the lowest temp intake and sounds the loudest. I guess getting the combination of all 3 isn't possible. I think the MAF mod won't work with a CAI???

""But, you'll have to know exactly how it was fueling before to know for sure if it was the intake and not an o2 sensor fading or something.""

Okay so I am doing that now as I've got an obi connected and I'm logging everything on torque pro. I've got lots of data logs already exported into spreadsheets. As an general average my overall trims are leaning towards slightly negative at present. When I do get this completed I can do some in depth analysis on the before and after shifts in open and closed loops.

Just jumping back to one of my questions, do you think a 3" coupler before the MAF will help smooth out airflow for the reading at the MAF??

Quote from: ChrisToffa on September 20, 2019, 20:11The best intake set up for a stock ECM is going to be one which advances the timing the most, has the lowest temp intake and sounds the loudest. I guess getting the combination of all 3 isn't possible. I think the MAF mod won't work with a CAI???

Advanced timing does not mean more power.

Bit of a common misconception. Torque drops off at both ends of the timing curve.
On the stock 1zz the most you'll gain from a couple degrees timing is some engine response. They'll already have it tuned for max brake torque minus a bit of safety margin. But timing curves plateau and drop, they don't peak. So there's a lot of margin you can add before losing significant torque.

A lot to be said for response though.. It makes the car feel quicker. I really enjoyed my advanced timing map on my piggyback . I miss it sometimes.

Lowest temps, yes; behind battery, enclosed  and with direct feed to enclosure from side vent I never exceeded 5-6deg over ambient when driving and 15c or so at standstill.
But, +/-2.5hp per 10c hotter... Never going to notice a diff unless on a very hot day at full chat.

Noise. Absolutely. Gotta love that induction roar. But, after a few years, I'm enjoying the silence of the stock intake now.

You forgot filtration. You have to make sure you're not just plopping a 15quid ebay filter on. You don't want your cylinders messed up for the sake of noise and a bit of throttle response.

MAF mod has worked for some with CAI. Trial and error. Usually has bad effects and people revert back to stock

Re coupler; it'll help fractionally . 3in over a diameter of 70mm is next to no distance for laminar flow.

For filtration I mentioned my preference would be a 70mm Apexi cone, the only other cheaper alternative I would consider is a Ramair, but I think the Apexi is going to sound the better.

What would happen if I put in a spacer under the MAF thus raising it? The MAF mod suggests that a 1/2" inch spacer slashes fuel trims down to -20. If I got a 1/4 inch spacer machined to fit, would this correct the +10 increase in FT's that you have previously mentioned on a standalone basis? Or does this not work without doing the MAF in it's entirety - (also removing the vanes also and adding the 310 injectors)???

Quote from: ChrisToffa on September 20, 2019, 19:40ns.

I really want to go with a behind the battery cone filter primarily for the acoustics and a tad better throttle response.

Best way to go would be to decuct the rear mudguard, cut the edge from the horn, drop in a foam filter.
That will give more intake sound and does not upset the ECU nor does it scare any horses up the scale.

(https://myalbum.com/photo/Bdb2CNjJnyp8/1k0.jpg)
(https://myalbum.com/photo/hHP8Rxgpjmwm/1k0.jpg)

Na tuning is a waste of time unless you spend ££££.

Get rid of the kinked pipe leading to the air intake and get a rorty sounding exhaust.

Job done.

Correct. It would be a trial/error.
Basically to get that trick to work for any intake other than stock, you have to go through the same process that Cap did on Spyderchat. Trial and error, monitoring AFRs, fuel trims, with vanes, without vanes, with different vanes, etc etc.

In short, you need to redesign the intake system to match the ecu.
I'll let you in on a secret though; Toyota already did it for you ;) haha

n/a tuning is a definitely a waste of money. I'd so much like to be in a position right now where I could drop in a 2zz or turbo.

I owned an Elise 111R for 18 months several years ago which as you know has a 2zz block so I know how dire a 1zz compares.

Meanwhile I'm just going to have to tweak with what I got for now. I certainly won't being doing anything more than a CAI + exhaust a stop gap.

Quote from: ChrisToffa on September 20, 2019, 19:40I want to quickly resurrect this intake discussion as it was going to be the next mod to my roadster, but after reading these posts I'm undecided and have some questions.

I really want to go with a behind the battery cone filter primarily for the acoustics and a tad better throttle response. I accept I might be losing a couple of hp or low end torque in doing so.

So ripping the stock intake pipe out of the airbox and retaining the all important vanes seems the best way to go.

It's suggested in these posts that still causes a positive shift in ST/FT's
Is this proven or an estimate?? Many who have fitted this set up comment that it runs well and seems to make no difference with the butt dyno. Was the actual before and after deltas in the trims actually recorded?

If there is a positive shift in FT's then can anything further be done to keep them to a minimum?

I see some people fit the cone straight on to the MAF pipe - would a 3" length silicone pipe between the MAF and cone help out further?

In the concept of the MAF mod, raising it's position in the pipe causes FT's to go negative. Can this idea be used to offset any increases?

If I do go ahead with this I will probably use a 70mm Apexi cone. Is this weight of all of this going  to be ok suspended from the throttle body or do I need to think about fabricating a support bracket?

If you want the easy route to a bit more growl then just pull the plastic elbow off before the airbox.

The subject has pretty much been done to death on this and previous threads, Shnazzle backed his findings up with his experiments and Cap over in the States went to great lengths to develop the MAF mod and document the results of changes to the standard arrangements.
There's no one hit answer to your questions really, the only thing that's guaranteed is as Ardent states, standard car runs best with standard setup.
The throttle body should be plenty strong enough to carry the weight but it's more to do with the type of hose and clamps you use, you're only getting around 20-30mm of hose onto the body so everything has to be nice and tight to stop the weight pulling the hose off.
Try and get the MAF as close to the standard distance away from the throttle body as possible as the ECU is expecting that volume of metered air, it'll be working hard all the time otherwise trying to compensate.
Failing all that get a piggyback and try your own experiments and find what works best for you.
You can't beat the growl from a big, open filter if that's what boils your kettle, just bear in mind there's not much soundproofing between you and the engine bay and it can get a bit tiresome on long hauls.👍🏻

Quote from: ChrisToffa on September 20, 2019, 21:31n/a tuning is a definitely a waste of money. I'd so much like to be in a position right now where I could drop in a 2zz or turbo.

I owned an Elise 111R for 18 months several years ago which as you know has a 2zz block so I know how dire a 1zz compares.

I prefer 1zz turbo to 2zz.
Not a fan really or k20.
I like torque.
Low down dirty torque.

Yep, there's not one perfect solution for this matter.

"pull the plastic elbow off before the airbox" and the intake temps no doubt go up pulling in air from that position.
stick with stock set up and be happy maintaining the hairdressers persona and sound of the car !
slap on a CAI behind the battery, solves the sound, response and reduces intake temps, but messes fuel trims!

nightmare.

I would get a 1zz piggy or standalone if an engine swap wasn't in my longer term plans.

Quote from: ChrisToffa on September 20, 2019, 23:46Yep, there's not one perfect solution for this matter.

"pull the plastic elbow off before the airbox" and the intake temps no doubt go up pulling in air from that position.
stick with stock set up and be happy maintaining the hairdressers persona and sound of the car !
slap on a CAI behind the battery, solves the sound, response and reduces intake temps, but messes fuel trims!

nightmare.

I would get a 1zz piggy or standalone if an engine swap wasn't in my longer term plans.

Removing the elbow adds a surprising amount of growl actually and intake temps don't go up by too much at all. 
If you're planning a swap anyway, and it's coming into colder temps, you have nothing to lose by removing it. 

It's really only on cooking hot summer days and long periods of traffic where you 'll get some soak. 
Add a good free flowing panel filter to that and you're 80% there. No impact on fueling. Other than perhaps a bit of positive due to less restrictive panel filter.

Quote from: ChrisToffa on September 20, 2019, 23:46Yep, there's not one perfect solution for this matter.

There is:
The deduduct/foam filter; intake sound, extra response, almost a kilo lighter and nooooo ECU issues.

I don´t know what you expect, but you are talking a filter mod only and having faffed with many more cras and motorcycles than I can possibly count, this is as good as it gets bar open bells and total rejet of Dell´Ortos but without the hassle of the latter!

Quote from: 1979scotte on September 20, 2019, 23:23I prefer 1zz turbo to 2zz.
Not a fan really or k20.
I like torque.
Low down dirty torque.

Still hoping to win the lottery one day. If that would happen, one thing would be a 1ZZ engine rebuild and TRD compressor fitted (bulkhead modded ofcourse).

Quote from: shnazzle on September 21, 2019, 07:48

Quote from: ChrisToffa on September 20, 2019, 23:46Yep, there's not one perfect solution for this matter.

"pull the plastic elbow off before the airbox" and the intake temps no doubt go up pulling in air from that position.
stick with stock set up and be happy maintaining the hairdressers persona and sound of the car !
slap on a CAI behind the battery, solves the sound, response and reduces intake temps, but messes fuel trims!

nightmare.

I would get a 1zz piggy or standalone if an engine swap wasn't in my longer term plans.

Removing the elbow adds a surprising amount of growl actually and intake temps don't go up by too much at all.

That's interesting, I will give it a go.
It's made me think then, if intake temps are ok in the area of the side panel and rear light then I could chop up a MAF tube, leave it in it's existing position and then route and intake pipe to that area made up with hose and a stainless tube.
This routing and shape of intake tract would replicate the AEM pipe, with a key difference in that the vanes will still be present in the intake. I would be certain that the AEM version would not have them as it appears to be one complete length of mandrel bent pipe. It also maintains the same intake tract post MAF.

Quote from: Petrus on September 21, 2019, 09:45

Quote from: 1979scotte on September 20, 2019, 23:23I prefer 1zz turbo to 2zz.
Not a fan really or k20.
I like torque.
Low down dirty torque.

Still hoping to win the lottery one day. If that would happen, one thing would be a 1ZZ engine rebuild and TRD compressor fitted (bulkhead modded ofcourse).

I wouldn't fit a TRD compressor if you bought me one. If you win the lottery I'd be thinking a bit bigger than that. Eaton TVS or whipple. Or rotrex but I think they work better on larger displacement imho.

Quote from: 1979scotte on September 21, 2019, 10:11

Quote from: Petrus on September 21, 2019, 09:45

Quote from: 1979scotte on September 20, 2019, 23:23I prefer 1zz turbo to 2zz.
Not a fan really or k20.
I like torque.
Low down dirty torque.

Still hoping to win the lottery one day. If that would happen, one thing would be a 1ZZ engine rebuild and TRD compressor fitted (bulkhead modded ofcourse).

I wouldn't fit a TRD compressor if you bought me one. If you win the lottery I'd be thinking a bit bigger than that. Eaton TVS or whipple. Or rotrex but I think they work better on larger displacement imho.

A Rotrex would be great too, but I lóve the stealth non-look of the TRD and not aiming high ;-)  Would spend some too on going lighter still :-)  Found another 30 kilos or so money cán buy.

Quote from: Petrus on September 21, 2019, 10:15

Quote from: 1979scotte on September 21, 2019, 10:11

Quote from: Petrus on September 21, 2019, 09:45

Quote from: 1979scotte on September 20, 2019, 23:23I prefer 1zz turbo to 2zz.
Not a fan really or k20.
I like torque.
Low down dirty torque.

Still hoping to win the lottery one day. If that would happen, one thing would be a 1ZZ engine rebuild and TRD compressor fitted (bulkhead modded ofcourse).

I wouldn't fit a TRD compressor if you bought me one. If you win the lottery I'd be thinking a bit bigger than that. Eaton TVS or whipple. Or rotrex but I think they work better on larger displacement imho.

A Rotrex would be great too, but I lóve the stealth non-look of the TRD and not aiming high ;-)  Would spend some too on going lighter still :-)  Found another 30 kilos or so money cán buy.

I love my Rotrex but I've 3l to fill in the bottom end. Not sure it works so well on smaller engines. Although if you rev the nuts off it I suppose it doesn't matter.

Quote from: 1979scotte on September 21, 2019, 10:27Although if you rev the nuts off it I suppose it doesn't matter.

Ah, but did we not start with apreciating the low end grunt?!  ;-)

Just dreamin´ though; sofar no lottery ticket win. Not literally; as a matter of speaking I have nooooo complaining.

Right, now for the problem of today; rivited wood rim or leather wrap??

On topic please gents. 
Intakes. Not engines or compressors :)

We have been running Caps MAF mod on 2 MR2s with stock airboxes (the one spacer even came from Cap).  It works as advertised, but only if you follow the directions exactly.  All experiments have shown a loss of power or poor running with any intake deviation (such as any air box mod, different height spacer, wrong injectors, etc). 

A friend did a before and after test on a dyno, and the mod added 5 hp. The only other mod in both tests was a Zero Exhaust header. Not bad for the cost of a set of injectors.  We have cheap clone headers and in normal driving, we get about 1-2 MPG improvement and better throttle response.

As a comparison, the same person added Crower stage 1 cams and a ported and flow benched head.  It didn't work well with the MAF mod and with the MAF spacer out and original injectors back in, they got almost exactly the same results as the stock engine with the mod.

As suggested, most CAI systems add noise and either do nothing or actually hurt power.  Unless you want to spend big bucks, most easy mods (like a header and / or MAF mod) will only give a couple HP at best

Here a photo of the rear mudguard duct and how the fresh air flows (or not).

(https://www.picclickimg.com/d/w1600/pict/202645958687_/Toyota-mr2-Mk3-seat-adjuster-covers-Trims-plastic.jpg)

Just noticed that last picture;
I never noticed that actually if you remove that side-panel, you can create a pretty nifty enclosed intake from side vent all the way to the stock airbox. 
So now it goes from side vent, into engine bay behind battery, into the duct in the side-panel, around the  back and into the back of the airbox. That little part where it goes into the engine bay could be cut out which surely would increase the efficiency. At the cost of giving your filter more work to do, as it is more likely to pick up gunk from the side vent as it no longer has a chance to deposit the dust/dirt into the engine bay before going into the intake.

The only issue is cooling. By enclosing it and routing it all int othe airbox, you lose all of the airflow from the side vent into the engine bay. Diffuser and flat floor could help with that to "suck" hot air out of the back. That's a lot of change though.



On another note; A bit more logging since going back to stock airbox with my opened up exhaust (Zero manifold and custom 200cell cat);

"Load" is now always a steady max of 100. Where it used to be higher than 100, somehow suggesting that manifold pressure was "boosted" somehow on my stock car, which is almost impossible given the intake tract. This also tells me that the ECU is very happy with what the MAF is sensing and it knows exactly how much load is on the engine as all the formulas make sense. Which means it knows exactly how much to fuel.

What I have noticed is that my MAF readings can max out as high as 120g/s. Significantly higher than what I saw with my Hurricane intake and even more significantly higher than stock (usually just around 95ish).
This suggests that the opening up of the exhaust has a significant effect on the car's ability to pump air. 
This is further supported by fuel trims being up by as much as 10%. So all in all, the car is pumping a significant amount more air over stock, and hence having to add more fuel, and hence more bang and power. So if you want to add performance on stock, definitely start with the exhaust system.

Intake temperatures, while definitely a bit higher than on my Hurricane, are well within reason and I would say that if I found a way to cool them towards ambient, I might gain about 2-4hp on a very hot day. ... Not worth it.
So once again I can unequivocally say that even without a dyno, my car is definitely putting out more power on the stock intake and improved exhaust than the stock car.
Next is to clean all logs and put a "performance" panel filter in and see what it does, other than let more crap into the engine.

Your analysis of the rear quarter space is spot on imo.
Imo removing the duct is as good as it gets without messing with the cooling.
Without the duct, making a bell mouth on the filter hornshould make the effective opening of that larger, but that is pretty much it and furthermore it is not the bottle neck on an n.a. engine; indeed the exhaust it is.

There is a lót of room for flow improvement there with the caveat that the OEM compromise between noise, emissions and flow can not be bettered. Any gains in flow will have a larger trade off.

Your logging of good metering and up to 10% extra fuel means that the output is 10% more too.
That is quite neat!
My set up probably flows a bit more but I´ll sign of on that  10% ;-)
Add the 15% lightness and we get 25% more fun :-)

Put the K&N filter in today after a good clean and re-oil. 
One thing to note, as I hypothesised above; the stock system is much better at keeping the air that comes into the filter as clean as possible due to the air gap behind the battery. 

The stock filter I took out was very clean. 

When I took the Hurricane element out after 6 months it was filthy. So, there's another benefit of stock.

First results are in after a week of driving with the K&N panel in and logging. 
The conclusion iiiiisss... 

Entirely inconclusive as the UK decided to bathe in the chill of plummeting temperatures, making it a bit of an apples/oranges comparison.

For what it's worth, yes MAF readings are consistently higher across the board. Comfortably peaking at 116-119g/s at full chat repeatedly.

Quote from: mr2noob on November 22, 2019, 13:50I love this guy, he destroys so many myths with such elan. :D

Yup. Basically everything we've (well, I for one) have been saying for a while. They're rubbish unless you change the ecu calibration but the key is MAF calibration. Mess with flow, you mess with MAF, you mess with ecu, you mess with power. 


You CAN have a very well-designed aftermarket specifically designed for the MR2 on a dyno, aimed at purposely changing the MAF reading such that it advances timing and makes you feel a bit more "oomph" but it's all fakery in the end.

Quote from: mr2noob on November 22, 2019, 16:24

Quote from: shnazzle on November 22, 2019, 15:34Yup. Basically everything we've (well, I for one) have been saying for a while. They're rubbish unless you change the ecu calibration but the key is MAF calibration. Mess with flow, you mess with MAF, you mess with ecu, you mess with power.

I binge-watched his video today and have to say most if not all the stuff he says is rock-solid, common sense advice. He seemed to have stepped on the balls of some British BMW fanboy though cause that guy launched a very undeserved primitive personal attack against Scotty. The last time I saw someone get that primitive, personal and uncivilized were two sellers at a food market in Eastern Europe.

I haven't found him talk rubbish about anything yet. Some people don't like him but I think that's mostly a personal thing as his voice can be a bit grating. 

All in all, can't knock what he's saying.
I think frustration is actually at the root of many of his videos. Crap he's had to deal with because people took their car to an idiot or because they've done something because Google said they should

Quote from: shnazzle on November 22, 2019, 18:07

Quote from: mr2noob on November 22, 2019, 16:24

Quote from: shnazzle on November 22, 2019, 15:34Yup. Basically everything we've (well, I for one) have been saying for a while. They're rubbish unless you change the ecu calibration but the key is MAF calibration. Mess with flow, you mess with MAF, you mess with ecu, you mess with power.

I binge-watched his video today and have to say most if not all the stuff he says is rock-solid, common sense advice. He seemed to have stepped on the balls of some British BMW fanboy though cause that guy launched a very undeserved primitive personal attack against Scotty. The last time I saw someone get that primitive, personal and uncivilized were two sellers at a food market in Eastern Europe.

I haven't found him talk rubbish about anything yet. Some people don't like him but I think that's mostly a personal thing as his voice can be a bit grating.

All in all, can't knock what he's saying.
I think frustration is actually at the root of many of his videos. Crap he's had to deal with because people took their car to an idiot or because they've done something because Google said they should

Usually I mute the sound and enable text so Mrs Joesson can read or watch TV without having to hear Scotty's dulcet  tones.

Found an illustration of the intake tract assembled; oh and the inlet horn/rlbow is fitted in reverse....


MR2InlaatCompleet.jpg

Looking to change the 45mm effective entry aperture


(https://myalbum.com/photo/BmSKSoaYEzaK/1k0.jpg)


for a 90mm one, increasing the entry surface fourfold:

(https://i.ebayimg.com/images/g/ca8AAOSwPCFeDydj/s-l1600.jpg)
(https://i.ebayimg.com/images/g/ZSQAAOSwikJb2GH8/s-l500.jpg)


Basically a TRD elbow with larger entry.

Just a small link back to my recent post on Caps MAF mod thread.

If you read that, it explains why an aftermarket intake is not good.
Take my Hurricane for example; consider it half a MAF mod. 
So, make the ECU read lower load,to advance timing... But without the extra fuel. So, basically you're making the car run lean. Which then gets trimmed out by the ECU via the o2 sensors. 
Pointless.

Quote from: shnazzle on April 26, 2020, 08:42Just a small link back to my recent post on Caps MAF mod thread.

If you read that, it explains why an aftermarket intake is not good.
Take my Hurricane for example; consider it half a MAF mod.
So, make the ECU read lower load,to advance timing... But without the extra fuel. So, basically you're making the car run lean. Which then gets trimmed out by the ECU via the o2 sensors.
Pointless.

Indeed.
Wíth the MAF mod however things change. Will come back to that.

The OEM air horn narrows down to a 45mm aperture, the Markiii elbow has no restriction, the TRD is all 70mm too ánd adds a bell mouth.
The TRD stub goes with a sports filter to make use of the less restricted entry.
Strangely enough the reported effect is marginal. I thus ´discarded´ them because the last few top end horses are not important to me anyway.

Derestricting the exhaust means that the inlet must flow more. Thus the OEM horn becomes more of a restriction but the effect of TRD/Markiii stub is marginal regardless so other limiting factors are involved.
As I am not focussed on top end power, this has not bothered me but thinking the MAF mod through with more time on my hand, my attention has focussed on the OEM elbow again as is literally the bottle neck at load regardless of the revs becaúse of the MAF mod:

Quote from: shnazzle on April 26, 2020, 08:35Remember the idea of the MAF mod wasn't to increase airflow or fueling.

However: Párt of the MAF mod is taking out the gate with the twin bars. Been looking at this and it is definitely restricting the flow, reducing the duct and creating turbulence. 
From post #83 in the MAF mod thread:

(https://uploads.tapatalk-cdn.com/20160708/16813eabdb4dd60cd720d769380e20c1.jpg)


This explaines why the TRD/Markii stubs have limited effect; there is anóther ristriction at the MAF sensor!  The vane at the MAF mod ís a definite restriction of the flow.
This makes the MAF mod very much part of the final words on the intake.
As  I have the MAF mod, that restriction is out thus the OEM horn is now the weak link.
So, out with the OEM one, in with a new.

With a straight inlet stub, the entry aperture becomes the critical part: Any turbulence will in effect restrict the passage way, hence the bell moutn on the TRD stub.
Because both the ready made Markii and TD stubs are thin on the ground and pricey, I can start with a clean sheet and go my own route with the brief of eliminating any bottle neck on entry.
Hence thinking to fit a funnel with a large bell mouth. The entry opening of the air box, where all the above are stuck ín, now becomes the minimum aperture.

Quote from: Petrus on April 26, 2020, 11:30

Quote from: shnazzle on April 26, 2020, 08:42Just a small link back to my recent post on Caps MAF mod thread.

If you read that, it explains why an aftermarket intake is not good.
Take my Hurricane for example; consider it half a MAF mod.
So, make the ECU read lower load,to advance timing... But without the extra fuel. So, basically you're making the car run lean. Which then gets trimmed out by the ECU via the o2 sensors.
Pointless.

Indeed.
Wíth the MAF mod however things change. Will come back to that.

The OEM air horn narrows down to a 45mm aperture, the Markiii elbow has no restriction, the TRD is all 70mm too ánd adds a bell mouth.
The TRD stub goes with a sports filter to make use of the less restricted entry.
Strangely enough the reported effect is marginal.

Derestricting the exhaust means that the inlet must flow more. Thus the OEM horn becomes more of a restriction but the effect of TRD/Markiii stub is marginal regardless so other limiting factors are involved.
As I am not focussed on top end power, this has not bothered me but thinking the MAF mod through with more time on my hand, my attention has focussed on the OEM elbow again as is literally the bottle neck at load regardless of the revs becaúse of the MAF mod:

Quote from: shnazzle on April 26, 2020, 08:35Remember the idea of the MAF mod wasn't to increase airflow or fueling.

However: Párt of the MAF mod is taking out the gate with the twin bars. Been looking at this and it is definitely restricting the flow, reducing the duct and creating turbulence.
From post #83 in the MAF mod thread:

(https://uploads.tapatalk-cdn.com/20160708/16813eabdb4dd60cd720d769380e20c1.jpg)

This explaines why the TRD/Markii stubs have limited effect; there is anóther ristriction at the MAF sensor!
Now I have the MAF mod, that restriction is out thus the OEM horn is now the weak link.
So, out with the OEM, in with a new.

With a straight inlet stub, the entry aperture becomes the critical part: Any turbulence will in effect restrict the passage way, hence the bell moutn on the TRD stub.
Because both the ready made Markii and TD stubs are thin on the ground and pricey, I can start with a clean sheet and go my own route with the brief of eliminating any bottle neck on entry.
Hence thinking to fit a funnel with a large bell mouth. The entry opening of the air box, where all the above are stuck ín, now becomes the minimum aperture.

Again, those veins were taken out not to remove restrictions. Cap's original thread shows the flow bench results and quite clearly shows that stock flows just as much CFM as a 200gbp filter with no veins. 

They were taken out to change the profile of air to create the necessary conditions for advancing timing.

Re the vanes and assumed restrictions, purely as a layman looking on, if the air has already got as far as the MAF and been metered then I can't see how the vanes can be a restriction?
The air can't do anything other than flow past them, once it's in, it's in. 
So yes, I can see that they could be seen as a restricted for the throttle body sucking air in but you're still always limited to the internal dimension of the stock MAF housing. 
Other than for pulling colder air from the outside of the car you could just pull the feed pipe off the airbox and still pull the same amount of air as you would through a 4ft trumpet.
It's been proven that a standard car, standard ECU will run with an aftermarket MAF without the vanes as countless people have done it.
Unfortunately very few have then gone on to produce any tested results other than reporting that it sounds great and "definitely goes faster"...
From what I've read Cap's mod works if run as Cap researched and devised it, anything else is experimental at best and as yet unproven.
As the great sages say, "leave it be, standard is the best" and I for one totally agree...

Quote from: shnazzle on April 26, 2020, 11:45Again, those veins were taken out not to remove restrictions. Cap's original thread shows the flow bench results and quite clearly shows that stock flows just as much CFM as a 200gbp filter with no veins.

They were taken out to change the profile of air to create the necessary conditions for advancing timing.

It is not whý they were taken out.

Quote from: Call the midlife! on April 26, 2020, 12:12Re the vanes and assumed restrictions, purely as a layman looking on, if the air has already got as far as the MAF and been metered then I can't see how the vanes can be a restriction?
The air can't do anything other than flow past them, once it's in, it's in.
So yes, I can see that they could be seen as a restricted for the throttle body sucking air in but you're still always limited to the internal dimension of the stock MAF housing.

The vanes sit just in frónt of the MAF.
They create a calibrated flow/turbulence which the MAF thén measures.

The plastic is a restriction just in front of the MAF body and the through photo illustrates it reduces the aperture.
Take it out and that area will potentially flow more.
If it does not, then the restriction is elsewhere.

Again; Cap Weir did not take it out to get more flow; it was part of his trick to advance the ignition.  Nevertheless have a look at it: Whichever way you look at it, it is a restrictor plate.
If that makes it easier, disconnect it in you mind from the MAF mod.
Imagine you find this gate in the inlet elbow.


(https://uploads.tapatalk-cdn.com/20160708/d24b68fa2fbc2c175dcfcb34219a8501.jpg)

Do you think is impairs free flow? Would you fít it between the TRD/Markii stub and the air box? At the entry of the air box?
Instead it sits in the exit of the airbox. You need to take it out of the airbox cover!  Basically the same thing as at the entry.
It is not part op the MAF housing. The MAF measures what flows throúgh this plate.

The MAF mod moves up the MAF so the calibration is out of the window anyway, the goál being to trick the ECU in ´measuring´ a low load. The side effect is that the vane is out.
It  wás no doubt part of the MAF calibration but taking it out = taking out a restriction.

Quote from: Petrus on April 26, 2020, 12:20Again; Cap Weir did not take it out to get more flow; it was part of his trick to advance the ignition. 

That's what I said :)

Theoretically yes, you're right. It is a restriction.
But there's theory and then there's reality for a given situation.
Given situation being that the diameter of that pipe + MAF + veins is more than sufficient for the 1zz to flow all the air it CAN flow stock.
And to prove the point further, the TTE turbo can flow enough air through that filter housing for 5psi of boost (and the associated vacuum created in the intake tract at full throttle).
And to take it yet another step further, the 2zz which had a CFM far higher than the 1zz, has the same setup (albeit a few mm bigger I/D).

MAF mod removes it as part of the "tuning" to the MAF being raised and injectors. Not to increase total possible airflow.

The twó main principles involved in the flow through an engine are:
1. pressure difference
2- inertia of gas mass

1. Without a difference in pressure, air stays put.
It only flows to equalise pressure.
Without lower pressure in the inlet, no air will go thataway.

An air intake in front of a moving car and an exhaust at the back will already see air flowing through open valves.
Adding a scoop will increase the pressure at that end,´charge´ the inlet, flow more air. This is why legally it is not permitted to add a scoop to the intake of a car not fitted with one as it changes the homologated flow.

This is irrespective of internal restrictions. Those restrictions only limit how múch ar flows between the two ends as they reduce the net pressure difference driving the flow.
Restrictions can be seen as resistors in an electrical current. Current flows to equalise a voltage difference. Each resistor will have a voltage difference at both ends but only if there ís a flow.
Same thing restructions in the air flow.
All restrictions/resistors added up result in a resting difference in pressure/voltage which ´drives´ the current of air/electricity.

ALLWAYS keep this in mind:
Pressure difference equals flow of air and vice versa.

2. the mass of the air flowing through a tube is again based on 1.; the inertia of the ´body´ of air is like a cork travelling through that tube; it will push slower air ahead and suck slower air behind it; again that pressure difference.
In guns this is a major pita as the projectile needs to first push out the air column sitting in front of it in the barrel and that is in effect an air shock absorber.

Now to our MR2.
If we would fit a scoop to the side vent, the engine WÍLL flow more air with the car moving forward.
The air scoop scoops up more air.
More air gets into the engine bay.
The pressure in the engine bay will rise, however little.
Thus the intake of the engine behind the battery will rise.
Thus the engine will breath in more air, however little.

Any restriction between the inlet and exhaust tip is like the electrical resistor.
There will be a pressure difference at either end of ány restriction.
Removing a small restriction will still see the total flow increase although only a little.
In turn, removing a larger restriction will see the pressure differce over other restrictions increase because of the increase in flow.
The comparison with a chain is very apt.

In the case of out MR2, Toyota has put a lót of effort to get maximium flow within the constraints of pollution and noise limits.
They have designed a chan with equal strength links.

If we owners to some extend ignore legal contraints, we can faff with the flow chain. If we take one restriction out, the flow increases but not all that much because the other restrictions will have an increase in pressure difference because of that.

All in all two main things to take into account when faffing with the flow of the engine:
1. removing ány restriction, however small relative to other restrictions will increase flow
2. any increase of flow will increase the pressure difference over every restriction

The latter applies to supercharging too ofcourse. In extreme cases the tubing on the suction side can collapse because of the difference with ambient air pressure.
If the intake of te turbo would be fitted with a bellmounth, than the flow into the engine bay becomes critical.
Although with an n.a. engine that is not much of a risk unless you make it breath through a plastic bag, it does illustrate the core principle; air only flows to equalise a pressure difference.

Looking at the OEM airbox, the engine will never flow more than can get into the duct through the quarter panel or with that removed into the space behind that panel.
On the other hand, adding a silly big scoop.... 8)


It´s both very simple and wonderfully complicated  :))

Quote from: shnazzle on April 26, 2020, 13:29And to prove the point further, the TTE turbo can flow enough air through that filter housing for 5psi of boost (and the associated vacuum created in the intake tract at full throttle).
And to take it yet another step further, the 2zz which had a CFM far higher than the 1zz, has the same setup (albeit a few mm bigger I/D).

Read my previous posts and you will understand that this is both a non-argument:

The turbo súcks as much as it needs t get at the limit set by the boost controlle. Restrictions in the inlet will see the boost reached later. It being reached is no proof of the inlet not being restrictive.

The few mms extra increase the aperture súrface with the square of the diameter which takes any ´proof´ out of the equasion.


As I wrote, your ECU adding up to 10% more fuel to the air means that the inlet flows up to 10% more, making any and each restriction in that tract more so.
The fact that it cán flow 10% more and in the case of a turbo 30%+ more, tells nóthing about how restrictive it or each restriction is. In only tells that there is enough súction to overcome the total of restrictions to pass that extra air.

Ergo, back to my OEM horn delete, the extra flow through MÝ engine has made the restriction of it more critical than it was before. The vane delete was just a spark igniting my mind, my chain of thought  :-o

I'm clearly not explaining what I mean correctly so, I give up :) 
Remove all restrictions at will :) 

It's weight savings in the end anyway so a win there

Quote from: shnazzle on April 26, 2020, 15:20Remove all restrictions at will :)

The calibrating vane already ís out.

QuoteIt's weight savings in the end anyway so a win there

Nope.
The silicone rubber elbow weighs about the same as the TRD alu one, a bit less than the steel Markii, but more than the OEM plastic one. It is thinwalled, lighter plastic ánd has on average less diameter.

Next; not exactly supercharging, just that more ín than OEM, ánd part of the intake  ;D


(https://i.ebayimg.com/images/g/URIAAOSwc~5a-orQ/s-l1600.jpg)
(https://i.ebayimg.com/images/g/ECgAAOSw7kVa-orE/s-l1600.jpg)

Quote from: Petrus on April 26, 2020, 15:57Next; not exactly supercharging, just that more ín than OEM, ánd part of the intake  ;D


(https://i.ebayimg.com/images/g/URIAAOSwc~5a-orQ/s-l1600.jpg)
(https://i.ebayimg.com/images/g/ECgAAOSw7kVa-orE/s-l1600.jpg)

Mesh = restriction :)

Quote from: shnazzle on April 26, 2020, 17:14Mesh = restriction :)

True and the surface not really larger either.

The only effective thing is one of those scoopes you stick to the outside of the OEM apertures. Fugly though to I´ll call it ok with the intake funnel.
Pressed the button and hope it will be here before the quarantaine is lifted.

Simple yet conclusive video on intake shapes.
The crux is at 4:15

https://www.youtube.com/watch?v=DX2HBYQp4YM

Remember that the duct through the rear quarter panel sucks through a flat panel behind the battery.
With the duct removed the space acts as a plenum chamber with, because it is open at several sides, flows more air that the OEM flat port hole.
The TRD elbow will thus flow potentially significantly more than the OEM hole.

As the exchange of views with Patrick has illustrated, the OEM set up is quite good enough to flow the OEM need: With an OEM exhaust, the deduct and TRD stub will make the engine flow very little extra.
Íf however you open up the exhaust, the engine will pass say 10% more air thus inherently ALWAYS, simply because of the increase in air speed, increase the resistance of the OEM intake system unless it is made equally larger/smoother*.
Nów the 15-20% increased potentiial flow of the TRD bell mouth wíll see an improvement in flow.

It is easy to understand just looking at an air filter. If a filter, ány filter is made to pass more air, it´s resistance to that flow wíll increase.
The whole of the intake system is functionally the same, just one big hole instead of many tiny ones: A higher speed of air wíll have more resistance.

Looking at a filter is also illustration the pressure drop thing of évery single restriction in the intake system: There is always a flow before and after every disruption of the flow and improving it will improve total flow.

Rank amateur alert.

I followed this thread with much interest and learning as I go.

My ? Understanding is that the 2zz uses the same airbox and same filter.
When that is in lift, it's sucking a whole lot more air than we are talking about here.
So my sticking point is, if a stock(ish) setup can provide for a 2zz on song, a nominal 10% on a 1zz is neither here nor there.

Back in my box.

Smacks palm of hand on head.
Overlooking the obvious.

My little entry level, forced induction setup, still uses the stock 1zz intake.

Quote from: Ardent on April 27, 2020, 20:44Rank amateur alert.

I followed this thread with much interest and learning as I go.

My ? Understanding is that the 2zz uses the same airbox and same filter.
When that is in lift, it's sucking a whole lot more air than we are talking about here.
So my sticking point is, if a stock(ish) setup can provide for a 2zz on song, a nominal 10% on a 1zz is neither here nor there.

Back in my box.

That's what I'm trying to say. Less clearly it seems.

Say the stock airbox has a hypothetical max flow without any bottleneck effect for OEM flow + 50%.
Then if you open up your exhaust and pump 25% more air, you're still 25% under the margin where you have to look at removing restrictions in the intake. That's the argument for staying stock. Hence there are at least 3 turbo setups I've seen that use a completely stock airbox setup. 

Changing the intake to change the availability of air at a particular power band does make sense.

This is the final word on intakes, everything else just blows... Or sucks...

Petrus, I'd be interested in the details of the parts you've ordered and how they fit.

I like the idea of a simple reversible induction mod that will make a bit of induction noise without hurting power. This looks like a great solution!

Quote from: shnazzle on April 27, 2020, 21:31Say the stock airbox has a hypothetical max flow

There is no max flow.

It is all about pressure difference.
The engine creates low pressure at the intake and high pressure at the exit.

Suck/push more and it will flow more. Albeit with increases resistance.
Increase the flow through a given system and the resistance increases.
Ergo; open up the exhaust and the inlet WÍLL become more restrictve.

It is paramount to understand that without pressure difference between in and out there is no flow.
An engine súcks in air from the outside.
The ouside is only ambient air pressure.
Hence tunin n.a. is mostly about marginal gains.

At 6.000 rpm the 1ZZ sucks say 45 liters of air per second through a 65 mm. tube.
This flow is propelled by a small pressure difference and the more difference is needed, the more the engine looses power in sucking. Same thing the exhaust side; the pushing.
Ány pressure drop over a minute resistance reduces overall pressure difference thus flow. Smoothing out the slightest mismatch, corner or lip wíll improove flow thus engine output.

The combo OEM airbox, MAF housing and intake manifold have proven to be critical in the pretty wel sorted ECU motor management. This is NOT saying that the flow cannot be improoved because it can. Delete the whole intake system, fit individual throttle bodies with bell mouths into a plenum chamber fed from the outside and the flow impooves a lot.
´A lot´ being relative because n.a. remains limited by sucking in atmospheric pressure air.



2ZZ: If anything the 2ZZ is a good example of there being room for improovemen in the flów of the 1ZZ intake system. Within the OEM 1ZZ system it does loose some hp.; has more pump losses. An istall with fully custom intake/exhaust/ECU pumps significantly more.

Turbo: will suck as much as it needs to up to the regulated max pressure. Less restriction makes it reach that at lower revs. Just as with the exhaust.
The TTE turbo install puttung out 30% more power, flowing 30% more air says NOTHING about the resistance of either inlet or exhaust. It simply means that the turbo provides enough pressure difference. Reduce resitance on either end and the installation will reach regulated max flow earlier.
Look at the OEM intake horn There is a serious restriction to reduce intake noise.There wíll be apressure drop over this restriction. A turbo installation sucking 30% more air through wíll increase this pressure drop, in other words increase the resistance.
TTE could not change this horn because of noise regulation. Swap it for a straight tube and max boost will be reached earlier.

As I obeserved earlier; look at it as an electrical circuit with a dozen resistor is series.
The is no max flow. That depends on the voltage difference.
Lower one resistance and the flow will increase till the voltage drop over all resistors equals the total voltage difference.

Quote from: Captain Vimes on April 28, 2020, 11:57Petrus, I'd be interested in the details of the parts you've ordered and how they fit.

I like the idea of a simple reversible induction mod that will make a bit of induction noise without hurting power. This looks like a great solution!

Will report when fitted.

Mind you, any straíght pipe between airbox and quarter panel duct will be easiest.
Several straight swap 45 degree pipes on ebay in aluminium.  You can even choose brushed or polished!
Per example http://www.ebaystores.co.uk/autosiliconehoses-outlet/45-Degree-/_i.html?_fsub=4833742011&

If you do the deduct then you can fit a bellmouth like the TRD pipe.
Also meaning you can choose to up the diameter as you can fit it óver the stub on the airbox instead of pushing it in. That makes a surprising difference in aperture; the wall tickness of the elbow + that of the stub x two.

Quote from: Petrus on April 28, 2020, 13:06

Quote from: shnazzle on April 27, 2020, 21:31Say the stock airbox has a hypothetical max flow

There is no max flow.

I KNOW!! That's why I said "hypothetical" for the purpose of the explanation. And I fully understand everything you're writing and you're right.
My point is; no matter how much you change the exhaust on a stock MR2, it will never increase flow such that you NEED to make micro-adjustments to intake.
You need to regard the scope of this thread. It is a stock MR2 engine with a stock ECU.
Exhaust modifications excluded.

But yes, absolutely, if you're building a custom tuned tubular manifold to straight through exhaust pipe, BW EFR 7163 turbo port the exhaust, port the head professionally, increase valve size, stronger valves, stiffer valve springs, increase bore, put different pistons in, stroker the crank, raise the head,high lift stg4 cams, custom tuned intake manifold with integrated positive displacement supercharger and small pulley, dual fuel rail for staged injection, nos and meth injection ports...
Then yes you may need to consider the angle of the velocity stack on your 100mm intake pipe

The point of this thread, as indicated in the post, is that for a "normal" MR2 without big modifications, you're going to get the best out of what the car can do with a stock intake,on a stock ECU. Value for money. Yes you can replace things before the airbox (trd pipe, velocity stack, straight to side vent, side scoops) but (in my opinion) they won't make a bit of difference. Anything you do shaping flow pre-filter goes out the window the second it hits the filter anyway.

As for changes after the filter.. Well then you're messing with the MAF calibration and you're well outside the scope of this thread.

Edit: having reread.. That setup above wouldn't give a shit about the angle of the stack :) Haha. But you get the point... Hopefully..

Quote from: shnazzle on April 28, 2020, 13:50The point of this thread, as indicated in the post, is that for a "normal" MR2 without big modifications, you're going to get the best out of what the car can do with a stock intake,on a stock ECU. Value for money. Yes you can replace things before the airbox (trd pipe, velocity stack, straight to side vent, side scoops) but (in my opinion) they won't make a bit of difference. Anything you do shaping flow pre-filter goes out the window the second it hits the filter anyway.

Marginal gains only but derestricting the exhaust flows say 10% more, making the gains maginally less marginal. A change in filter element will be slightly more ´important´ p.e.

QuoteAs for changes after the filter.. Well then you're messing with the MAF calibration and you're well outside the scope of this thread.

MAF mod?
I´d say it´s part of the words on the intake.


I think we are mostly following different tracks.
On a stock car, there is very marginal gains in swapping the filter element for a ´sports´ one even. I agree.
Fitting a Markii of TRD stack same thing. If anything it is surprising that owners notice a difference.

Fitting a TRD filter and TRD elbow (duct delete) same thing. It will make marginal differnence only as the largest restriction is in the exhaust.


Once a sports cat and better flowing muffler are fitted things change as the system flows more.
Ok, still marginal but 10% more flow is marginal plus 10% :-)

The MAF mod. No, not méant to improve flow, ´just´ more advance. This gives a more efficient burn, a bigger bang driving the pump. The measured increase in 5hp output means that there is more flow. Power increase = flow increase.

The final word on intakes thus is subject to the perspective of other mods.
Also we are both still faffing about with the OEM aibox, MAF houding, intake manifold. We agree there; that even with full racing exhaust that still is a well matched intake combo.

Now a different thought:
Several have observed that after market filters taking air from behing the LHS rear light, thus the rear quarter panel space, collect more dirt than the OEM filter.
I have observed the same after the deduct. The same OEM elbow, just the deduct.
In itself not so surprising as the space is not hermetically closed. Air form behind the car, evenso from the wheel well can enter. This is more dusty.

The crux is that it illustrates the effect of opening up flow channels. The OEM channel being the duct hooking up to the panel inside the engine bay, from there sucking air indirectly from the side vent.
Disconnecting from the duct or removing the duct sees air entering from other openings too even though these are smaller that the OEM entry still in place.
I mean; I still have the same OEM air horn. The hole behind the battery is still the same, the side vent is still the same. The air cán still take the same path; I only took the duct out.
This means that there is a pressure drop over the OEM path.
Mind that was before fitting the decat midpipe and MAF mod so with pretty much OEM airflow.
This means that there is a pressure drop over the OEM path befóre the filter box with a pretty much standard 1ZZ.
I will btw try seal some of the openings to the wheel well with duct tape.

This thought also illustrates that the battery is part of the intake. Take it out and you will immediatley see that the entry/flow fom the side vent changes, gets more space.
In the context of cooling this has been mentioned already.
I am not clear whether the battery improves or impairs flow from the vent to the entry of the duct.
You, Patrick, mentioned the potential connecting of the duct to a hole in the cowling inside the vent. That would improve from into the duct but also impair the fow of cool air into the engine bay.

For an idea of the flow and volumes we are dealing with: At 6000 rmp the engine sucks in the whole volume of the air behind the quarter panel within a second...

Not read the whole thread but its probably been said that a closed filter like my BCM CDA and a cold air feed from the side scoop makes a hell of a difference to performance IME as it will give a ram effect. When fitting the 2zz back in mine I forgot to re-fit the cold air feed (ducting) and the car just felt lethargic. Figures, as all the intake was doing was sucking up very hot engine bay air. Re-fitted the air feed to the side scoop and what a difference in all round performance. This just tells you that an open cone filter in the engine bay will actually reduce performance over the stock air box.

Never experienced a OE filter box in mine but would be interesting to see the difference. I will log fuel trims to see what this BCM is doing and report back.

Having read all of this thread again, I think it has served its purpose and nothing new has been contributed for a good while. So locking it down. 

The key to the thread lies in the 3rd paragraph of the first post. This defines the scope of the claim.

There should be a follow-up thread though;
An empirical "study" in the effects on airflow from changed to the exhaust. 
In other words, showing the net effects of changing the exhaust components in various ways. 

I made the claim as well that exhaust changes are the way forward, but it would be good to see this in numbers from someone who has measured using full OEM, decat mani on OEM, sports cat on OEM. Decat mani and sports cat on OEM, mani + full decat... Etc etc. 

May the force be with you.