Tuning Questions using 2g Maf

CarPsyco84 · 11-25-2009

I'm having a tough time with tuning the partial throttle on my 1g, I have a 50 trim with a 2g maf. The issue is goes way rich at lower rpm partial throttle and even while crusing if I start going up a hill, like the -10in/Hg to say 5psi. My Maf is really close to the turbo, anyone had any issues with that before? Cause it's almost like the reported airflow to the computer is influenced some by the turbo. I have a crushed 1g bov also, but I know that it doesn't leak out air unless you start making boost to blow off. Seems to get worse, the warmer the car gets, any ideas?

4g63tcrazy · 11-25-2009

What are you tuning with? Have you done a boost leak test? You say you know your bov doesn't leak cause your not making boost but then in your description you say anywhere from 10in/hg to 5psi. Which doesn't make much sense.

CarPsyco84 · 11-25-2009

Ok, to clarify, the car runs awsome at WOT 30psi... its litterally when I'm not making boost when it runs like shit. My questions I guess are, can the 2g Maf be too close to the turbo? If the blow off valve is tight (not like a stock one where its open under vacuum) could that cause air flow issues with the Maf? Its currently vented to atmosphere, but that isn't the issue here, because I put a hose back into the intake from the BOV and it still had issues. It just seems like if you get the turbo spinning a lil bit, it causes the Maf to read higher hz than it should... Its hard to explain, but if theres some tricks to a 2g maf in a 1g I'm all ears.

4g63tcrazy · 11-25-2009

Your bov will blow off when you get anywhere from 5in/hg + up into boost. With you venting your bov, your car is expecting that air to be there. Yeah its only just a little bit of air but your car will easily go 10.0 off the scale rich just from that. I know you said you recirculated your bov but that is why your car is going rich like that. The reason it still did that while you recirculated it is cause your bov is probly crushed too tight and not opening at that low of boost level and the car still isnt seeing the air it should. Stop venting, recirculate the bov, and get an aftermarket one to hold that much boost, while still being able to open at a lower amount.

CarPsyco84 · 11-25-2009

yeah, but it goes rich even when I'm not letting up on the gas, like going up a hill on the freeway or accelerating slightly, it doesn't happen instantly, it starts building over like 5 seconds or so, my Hz on the SAFC will go from like 300 to 600 but the vacuum doesn't change it would still be like -5in/Hg

4g63tcrazy · 11-25-2009

Have you done a boost leak test?

niterydr · 11-25-2009

Yes your MAS is probably to close to the turbocharger and is getting some feedback. Since the air is being pushed back through the MAS it is being counted twice, and thus your computer puts in more fuel, thus you run richer.

Move it farther away from your turbocharger. The OEM's design the systems to have a good chunk of distance (usually at least 6") from the throttle opening for this exact reason (or in your case the turbocharger). Airflow path needs to be straight leading into and out of the MAS sensor for it to work correctly.

CarPsyco84 · 11-25-2009

Ahhh, that would make sense ill have to fit some pipe in there to make it farther away, 1g's are kind of a tight fit...

**asshanson** · 11-26-2009

Do you have the 2g mas only a couple inches away from the turbo? Or at the stock location?

CarPsyco84 · 11-26-2009

It was basicly coupled right onto the turbo, that 2g maf with filter assembly takes up alot of room compaired to a stock maf. Obviously thats why no one ever puts the maf that close to the turbo.

CarPsyco84 · 11-26-2009

Just to make note for future reference, the Maf was too close to the turbo and that was what caused the issues, thanx Niterydr.

niterydr · 11-26-2009

Quote:

Originally Posted by CarPsyco84

Just to make note for future reference, the Maf was too close to the turbo and that was what caused the issues, thanx Niterydr.

No problem, why I am here.