MX-3.com

so to clear things up....i can(should) run my MAF before the turbo(filter..MAf..Turbo) on my 1994 DOHC B6 using the stock MAF with an open atmosphere blow off valve(turbo XS RFL)...and will not have any idle or rich/lean problems??

Also there shouldnt be any problems extending the MAf plug wires about 1 foot??

no. that will cause problems, what it seems that people are saying is go filter -> turbo -> bov -> maf -> tb -> Im exct exct.

Bochek

Bochek wrote:it is impossible to use the bov before the maf.

maf has to be before the turbo, and bov has to be after the turbo.

Bochek

OR use a super AFC which can compensate for the blow off into atmosphere! Thats what im doin. car runs fine. My car goes -air filter-MAF-turbo-intercooler-bov-tb.

am also running the exact setup as cjthor, with a TurboXS Type S BOV which vents to atmosphere and it works fine. Running 10+ psi with no problems.

Thanks! is this the setup you have ? Filter -> MAF -> Turbo -> IC -> BOV -> TB . ive seen this setup befor dose it work ok / Idle fine

Ok what i am getting poeple are saying to run the MAF betwwen the turbo and filter??

Boy this topic is confusing
Someone please give a definate answer!!!

Joey's mx wrote:

Bochek wrote:it is impossible to use the bov before the maf.

maf has to be before the turbo, and bov has to be after the turbo.

Bochek

OR use a super AFC which can compensate for the blow off into atmosphere! Thats what im doin. car runs fine. My car goes -air filter-MAF-turbo-intercooler-bov-tb.

am also running the exact setup as cjthor, with a TurboXS Type S BOV which vents to atmosphere and it works fine. Running 10+ psi with no problems.

Thanks! is this the setup you have ? Filter -> MAF -> Turbo -> IC -> BOV -> TB . ive seen this setup befor dose it work ok / Idle fine

Ok what i am getting poeple are saying to run the MAF betwwen the turbo and filter??

Boy this topic is confusing
Someone please give a definate answer!!!

Dude...all of us said the same thing here.....
AIR FILTER>>>MAF>>>TURBO>>>INTERCOOLER>>>BOV>>>TB

ModMX3--Yes, holes were cut out under neath each headlight to run the piping through. Its not the perttiest, and its now all but impossible to change a haedlight lamp...but it gets the job done. My bov can still be heard, but its not that loud at all like an open atmosphere one is. Someday I'll get an safc or some other kind of piggyback / standalone...so I can better tune the car and run a bov to the atmosphere...all in time i suppose.

Here are a couple shots that show where the pipes / holes are:

Dude...all of us said the same thing here.....
AIR FILTER>>>MAF>>>TURBO>>>INTERCOOLER>>>BOV>>>TB

Ok i got that now..but one more question is everyone who is runnign it that way have some kind of fuel computer to fix any problems?? Or does it just work fine like that with an open atmoshper BOV??

cjthor wrote:OR use a super AFC which can compensate for the blow off into atmosphere! Thats what im doin. car runs fine. My car goes -air filter-MAF-turbo-intercooler-bov-tb.

This is going to be the only way you can compensate for an atmosphere BOV. You cannot run a bov to atmosphere unless you either want a lean condition or having to go piggyback. I run an Apexi Super AFC and have no probs...

so no matter what you will have soem kind of problem with leaning out?? I mean running the MAf both ways??

Well this seems to be an unsure subject for everyone. I will run the MAF befor the turbo and see how that gos. Then maybe ill try it after the turbo just to compair differences. That way maybe we can clear things up a bit.

if u run the maf befor the turbo with an atmosphere BOV and not tuning it for that application u will run RICH when the BOV goes off.

ok, i dont think you can use a maf after the turbo, but you can use a vaf after the turbo, i think this is where we are all getting confused.

would a turbo expert please comment on this.

Thanks,
Bochek

I'm no turbo expert, but the 4cyl have MAF and the V6's have VAFM. I know for a fact from looking at BabyBlue's Cardomain pictures that he runs the VAFM after the turbo, and that is how I've seen just about every v6 K8 ran. I would imagine that your MAF should be as close to your TB as possible because otherwise there will be escaping air (BOV, Wastegate, IC leakage) that would hinder the measurements made by the ecu for fuel/air ratios as virtually useless and make you run lean. I have never researched into the 4cyl Turbo applications, so I can't speak for the 4cyl members. Your best bet is to use the Search function and look at pictures of other member's applications.

-Curt-

If the MAF also reads temp, you would think it would be best to put it after the turbo , to best moniter the incoming air flow/temp . the downfall of this would be it would run rich every time the BOV is opened. I would think that running your MAF befor your turbo would be best with an atmospherfic BOV if your not using some kind of electronic fuel control. allthough then it would not adjust fuel acorrding to temp so either way it seems unsure but if I would have to choose I would rather run rich then lean.

INtake---> turbo--->intercool---> BOV----> MAF/VAF------> TB. That way if the BOV release air that air is not already measured by the MAF/VAF. And so u can have the correct IAT of the compressed air.

Well if you think of it like this.

You don't want any of the air's quality's to change between the MAF and yout TB...otherwise the calculations it makes for the fuel/air will be incorrect. If you have the Turbo, BOV, and wastegate after the MAF...then the calculations will be incorrect and you will either run Lean or rich because the air's quality's have changed since they were measured by the MAF.


Hope that helps you grasp the concept that I see in my head.

-Curt-