I think the easiest way to dial in the air/fuel ratio is an adjustable MAF. Not sure what options exist for the M3 - if any exist at all. I was impressed how easy it was for the dyno guys to dail in Martin's car using the controller that came with the pro-flow maf (www.pro-flow.com).

This isn't to say there isn't some sort of problem too. Pinging sure suggests somethings wrong, doesn't it? Does the M3 motor have adjustable cams/Vanos? Might check to make sure that mechanism is working correctly. Trust you've gone thru all the other usual suspects:

- fuel pressure and flow
- fuel quality
- tune up / quality ignition
- vacuum leaks
- blah blah blah...

Curious how it turns out...

Jeff




Quote Originally Posted by TC535i
Another interesting tidbit, there was a sharp dip in the graph around 6,000 rpm, probably the engine retarding the timing due to detonation. What bothers me is that the A/F ration was 13:1 at that point (plenty of gas), hood open, fan blowing on the intake (CAI/airbox), good Chevron 91 octane, and she's running Denso plugs 1 temp range colder than stock... why the hell would it be detonation? We've heard pinging on occasion too, can't figure out why it would do that. Any guesses?