Infini IV

http://13b.power.ne.jp/main_contents...kojin/sfc3.jpg

Just want to know the downsides to having the AFM aft of the intercooler so that the air's blowing through it?

Are there any downsides? A friend told me you get better response among others I forgot.

mrb63083

iTrader: (4)

with a fms you can ditch the afm, and not have to worry about it.

FastX7

It can blow a hose off anywhere before the AFM and still run for one...
I would think the ECU would have a better understanding of how much air the engine was injesting allowing it to be more accurate instead of measureing the intake air then references the boost sensor.
The boost sensor could also be rid of I would think as well. Since the AFM's measureing all the air, you wouldn't need it any more.

Samps

It's absurd to run that kind of equipment off of the stock ECU.

Jahoo88

If you mount it close to the tb, after the BOV i think it would run much better then before the turbo. It would have better response and no hesitation whith an atmosphere vented BOV.

I was gonna do this and i think i still may give it a try, only downside i can think of is you have to extend the wiring to the other side of the engine bay.

FastX7

I've ONLY seen that kind of set up on Japanese 7's. I'm curious as to how it works. All I can think of is that the boost sensor is useless because the AFM is seeing the EXACT amount of airflow. It would definitely take some experimenting.

Jahoo88

Well.... the boost sensor controls timing so it is still needed.
The computer knows the exact amount of air in a stock setup also other then when an atmo BOV blows air off.

FastX7

Yea, I know the computer sees the amount... but with the AFM after the turbo, the actual AFM is seeing the amount of air. It's not being "interpreted" with the boost sensor.

capsoval

The primary reason for doing this was probably the bov. On the stock system if you used a atmosphere bov, the engine would go rich for a second when it would vent. If you put the afm after the turbo and the bov between the turbo and the afm there will be no change in A/F ratio at the time of vent. This is how it was done on my car.

FastX7

What'd you have to do to run that setup? Anything other than just moving the AFM?

NZConvertible

All the AFM measures is the velocity and the temperature of the air passing through it so the ECU can calculate mass airflow. This amount will be exactly the same no matter where you put the AFM. The boost sensor has nothing to do with this.
The boost sensor controls ignition timing and has nothing to do with measuring airflow.

FastX7

Well, like I Said above... I was just speculating with all that. I in now way claimed to know what I was talking about :p

Jahoo88

Capsoval: How did you extend the wiring to reach the new afm position?

Aaron Cake

iTrader: (1)

Just remember that the AFM is not meant to be pressurized. Also, there is a temp sensor in the AFM, so the higher temps past the turbo will change the reading of that sensor.

I can't think of any advantage to putting the AFM in the intercooler piping, except perhaps if you have no other choice (lack of space for it before the turbo). The disadvantages, however, I mentioned in the first paragraph.