Quote: Originally Posted by westrock
If the PCM goes into open mode when WOT, it will never know the air fuel ratios either before or after.
But if it's going off tables such as the fuel trim cells and they get altered it may correct for it somewhat even at WOT. Without knowing the PCM programming we can only guess or test and reverse engineer what its doing.
I don't think anyone is getting too defensive, just discussing. The curves on the car do look somewhat odd but I bet the results would be comparable on another car. It would be nice to what happens on a properly running car. I'll have to put some thought into the potential effects and the pro/cons of it on my drive home tonight. It isn't exactly like a manual boost controller, MAP clamp, etc., but the results may be similar. As for the A/F it was just a comment that
you might be careful about running over 12:1 on a dyno
with any type of modification including this one. Right now you don't have the fuel to support that extra boost (and even more so out on the street).
And timing is important, particularly on a car that's already heavily modified and might try something like this. For example, if for some reason someone tried this in combination with a MBC they could already be running lean and the decreased timing would increase EGT's, which would increase the chance of knock. Everything affects something else and is in itself being effected upon.
I don't care only what vendors say and their testimonials and dyno graphs, but I like to see the overall picture of how an engine is running and
how it's making the power. That's why I would like to see how the IAT is affecting timing in addition to the effects on boost, A/F and overall power. More knowledge makes it easier to figure out the cause—affect relationships. Keep up the good work and post what you find.
Perhaps someone in your area with a scan tool can help find out some more insight in what's going on. The last car that I tried to trick the PCM via IAT changes turned out to not to even have any of the O2 sensors plugged in! And it was running surprisingly well with like that with a big turbo and S-AFC.
