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Old 11-07-2012, 10:52 AM   #32
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Join Date: Dec 2003
Location: Wichita
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My Ride: 2011 E90 M3
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Originally Posted by NickG View Post
No forced induction setup should run the IAT sensor BEFORE the compressor/turbo. That is just plain faulty engineering and a recipe for disaster. The sensor needs to be post-compressor/charge cooler so the ECU gets an accurate measure of the charge temp entering the cylinders. With the sensor before the compressor, there's no way to compensate for a faulty charge cooler or heat soak.

And for the record, the MS45's IAT sensor transfer function is DIFFERENT than that of the MS41/42/43 IAT sensor. Don't think you can just replace one for the other and your problems are solved.
So maybe in my case (original tune,pre-current build) AA made the car run rich as a pre-compensation for when heatsoak kicks in. I would have been OK with that but it has never been explained to me that way.

I'm leaning more towards a standalone ECU. I don't think my shop can really splice out the IAT in the MAF and install it in the intake mani. I'm not sure I'm willing to spend the $$$ to do that. Rather just go with a stand alone so I can tune the car myself and not need to deal with remote tuning and needless complications for a track car.
2013 F30 328i - Melbourne Red
2011 E90 M3 - Monte Carlo Blue
2004 E46 M3 - Imola red
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