alrite i havent been lookin on the boards too much lately... due to the fact that soon ill be driving a galant VR4 for about 5 months ( hey atleast its a TOTAL sleeper ) but i was thinking that if i moved the MAF to after the intercooler that i would still be getting the same reading to the computer and it would be less restrictive on the turbo has anyone done this? any dyno gains? anyone done this.... im bored and i wanna try something new. anywho drop me a line!!!

ps. wouldnt your turbowhine get much louder with this mod? just a thought for you if you like turbo sounds

 

"search"
You are not the first to come up with this. There was a very recent post by Dale on the subject. He discusses how 500 hp Japan Fc's have done this for years.

 

but pressing the search button is so hard!

 

Ive heard the flapper slams open once you get boost. Its not made to withstand the heat of the air after the turbo and there is a temp sensor in the afm. I thought about doing it and decided not to.

 

Temp sensor is in the throttle elbow on TII's. The heat after the intercooler should be fine.

Again, they do this in Japan on 500 hp cars. It must do something. And slamming open... just doesn't make sense....

 

UMM...air flow AFTER the intercooler will be fine. Flapper door slamming? WTF? Your joking right?

I've seen plenty of the AFM FC's with this "mod"...they run just fine.

 

slam da da da let eh boys be boys! (onyx)
yeah you will be fine, old trick

 

it's an AFM, not a MAF. BIIIIG difference.

 

so how do u do it? make wires longer and jus shove it in there?

 

yep i used speaker wire once to extend em! lol!

 

So why would you do this anyway? What advantage does it give you?

 

A restriction is a restriction, no matter where you put it. Remember airflow (l/s, cfm) before the turbo is exactly the same as after it (pretty obvious really), so the pressure drop across the AFM will be exactly the same wherever you put it. Boost is irrelevant here, only airflow matters.

 

There is also an air temp sensor built into the AFM. This is necessary because the AFM measures air volume flow (l/s), but the ECU needs to know air mass flow (kg/s) to calculate fuel requirements. For a constant mass, volume varies with temp, so by measuring volume flow and temp the ECU can calculate mass flow.

 

Not true actually, the mass flow is constant but the l/s (volume) will be less after the turbo than before during boost (as the air is compressed). I've always kinda wondered about this mod as I don't see how you can get the same readings from the AFM independant of boost. Basic physics would say you don't due to the change in velocity of the airflow. As an analogy, take a garden hose and drop the water against a surface, now squeeze off the opening to get a stream and spray it at the same surface - same amount of water flow (mass/s) but much different force on the surface (due to the higher velocity). The AFM will read low under boost, linearly so with boost if my math is correct.

For the guys running 500hp on this, they're obviously not running stock ECU's so all bets are off as you could compensate for this in the ECU.

Henrik
87TII

 

Lots of extra fuel pressure, LOL. However, it seems to me that the car would run more lean as boost increases because of the added heat. It makes me wonder how true the rumors are about this mod. I don't suppose anybody has a picture?

 

To me, this seems like a pretty hardcore mod to get the most possible power. And most hardcore guys have a standalone. And most people with standalones get rid of the afm altogether.

 

ive heard of the mod but have no interest in doing it. the AFM is a restriction, plain and simple. the only way to make air flow better is to remove the AFM, with a standalone. i intend to do just that.

btw-if it was done, i would imagine the turbo would make a good bit more noise. its prolly the only reason i would do such a mod.