Final word on intakes

[shnazzle]

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

Mesh = restriction

[Petrus]

Mesh = 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.

[Petrus]

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.

[Ardent]

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.

[Ardent]

Smacks palm of hand on head.
Overlooking the obvious.

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

[shnazzle]

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.

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.

[Call the midlife!]

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

[Captain Vimes]

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!

[Petrus]

Say 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.

[Petrus]

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!

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.

[shnazzle]

Say 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..

[Petrus]

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.

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.

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.

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...

[JB21]

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.

[shnazzle]

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.