1seriouspig's logs (v. positive deviation issues)

[SoSlow]

quick mod list..
stage 3 homebrew w/ ko3/ko4 hybrids. greentops w/ 4 bar. MBC only. TCD. bmw 540i maf, bmw 540i intake filter

ok so, i know the car is running a bit rich but it shouldnt be that much of an issue

look at how the car runs at 14psi(spikes to 16):



looks to me like it's running alright, aside from richness, timing seems decent. and it doesnt throw any codes

but now look at how the car runs at 19psi(spikes to 21):



as soon as it hits anything over about 17 or 18psi it throws the positive deviation code, and you can see the results in the log

[PSmalls::DoggieStyle]

From my experience, the car pulls timing once you get into the 300s for MAF values. You need a bigger MAF housing, curious what you're running now. Obviously, you also need to pull fuel. You say it's no big deal, but it really is. It'll make a biiiiiiig difference.

I have no idea what to tell you on the positive deviation. That makes very little sense since you have a TCD. If anything, you might get a *negative* deviation code when running XR and/or living very close to sea level where ambient pressure is high (>1000 "idle" boost). The only thing it could maybe be is the quick spool-up causing the code, but I thought this car was using X chip for homebrew? I could understand this when using APR or something like that, but not X....

[SoSlow]

[PSmalls::DoggieStyle]

Maybe it's the intake that is overinflating the #s. You shouldn't be pushing that much air with that little bit of boost. For comparison sake. I run straight K04s at ~22.5 psi peak boost tapering to ~20.5 psi near redline in a 83mm MAF (same size as 540 or very similar) and only barely hit 270 g/s. IIRC, this car is only on K03/K04s. That makes it even harder to believe, lol. Or maybe you actually have a boost leak......

[SoSlow]

by a local shop, they 'claim' it has no boost leaks, i do not know the authenticity of said pressure test.

so, what do you recommend?

[PSmalls::DoggieStyle]

FWIW, Mike Moore and I run stock airbox modified to fit bigger MAF housing. Apparently, it works pretty well. You could try that.

[SoSlow]

it has been modified similar to the evo style intake to block off engine heat

[PSmalls::DoggieStyle]

I've seen "hot air" cone intake filters do that before. I wouldn't be suprised if that was the case here since your MAF values are way off based on your turbos and boost. Leave it as is if you want, but your car isn't running well IMO. How much fuel have you pulled on your homebrew setup to still have such high 02 voltages? If't it is anywhere near 25%, I would totally say your intake is the problem, overinflating the MAF values which results in a rich condition because the car thinks you're flowing more air than you actually are and thus injecting more fuel than you actually need.

[SoSlow]

[PSmalls::DoggieStyle]

People think their cars are fine, but their MAF values are crazy high and they can't seem to pull enough fuel for a good AFR. That means everything is pointing towards your intake being the culprit.