A/F meter bypass to increase flow reading

[BOOSTD]

I have been experimenting with a small filter placed after the Stock Air Flow meter to reduce the air the meter see's and therefore increases the readable hp range. I have had my car running with adjustments made to the AirFlow %correction on my Power FC. ie 20% air bypassed through my little filter at idle then the correction will be 120% and so on from 0-5v

I am unsure if the fine tunning capabilities will be effected with this setup. I have seen numerous other vehicle modified like this for cost effective measures. Is it worth it?? I don't know. Has anyone done/seen/heard of this before with a Power FC?

Cheers Matt

[Busky2k]

Thats a strange technique I have to admit. But remember as the revs climb, the hole will become more restrictive so it wont be a linear relationship between revs and air flow correction. You'll probably need to dyno it to get it correct!

[BOOSTD]

Most definitely, the Airflow correction table enables me to firstly get the mixtures into the ball park before dyno tunning on the map. Alot of standard Air flow meters work the same with a bypass. ie VR4

[Steve]

hmm, what about the differences between air density from cold to hot days? without temp correction I think you may be asking for trouble when the air temperatures fall.

[EnricoPalazzo]

matty, good to hear from u mate.

Anyway next week, my car is gettin retuned, and hopefully will be able to somehow get around the stock limitations of the afm. I will find out how they do it and get back to u.

cys

[BOOSTD]

Steve: I see what you are saying, the unmeasured air being bypassed will increase and decrease with air temp and there for will reduce the ability to fine tune... to a degree. Maybe a VR4 has a air temp sensor aswell as the MAF sensor which would compenstate for the bypassed air..... hmmn all very interesting. I think idle might suffer aswell as the amount of air is so small and slight variations will be even slighter and cause hunting.

dean: the problem with the stock a/f meter is once it has passed 5.1v you are only able to tune for one boost level. Air temp also causes mixtures to change uncontrolably aswell. So basically you can't fine tune with any stable mixtures after maxing the meter. I found I had to compensate alot for various temperatures continuously - a real pain in the butt. My car runs different boost in all gears so the extra resolution will help me greatly.