Final word on intakes

[shnazzle]

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

[Call the midlife!]

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.

[shnazzle]

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.

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.

[Gaz mr-s]

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.

Do tell.....

[Gaz mr-s]

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

[Carolyn]

I don't think it does

[Petrus]

Since 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.

[shnazzle]

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.

[Petrus]

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

Also:

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

[m1tch]

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.

[shnazzle]

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.

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

[Call the midlife!]

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.

[Beachbum957]

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.

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.

[shnazzle]

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.

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

[Alex Knight]

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?

[shnazzle]

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?

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.

[Call the midlife!]

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?

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?

[The Other Stu]

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.

[househead]

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.

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?

[Petrus]

I 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.

[Petrus]

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?

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.

[Petrus]

...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.



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

[Dev]

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?

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.   

[shnazzle]

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.

[Petrus]

or 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.