OK - after a break for a while, I'm back to trying to tune out my modified M30 motor. Serveral observations:

First, my engine performes better at low to mid throttole on the cold run cycle. I believe this is because of added low speed timing advance. (My wideband 02 suggests my mixture is OK) The theory that I'd like to validate is

- if the mixture is richer than stoich, you want to advance the ignition timing at low RPMs. Richer mixture needs more time to ignite thus the added advance.

Second, my engine looses noticable power on hot days (80 degrees F+). I am running a MAF and AIT sensor (Air Intake Sensor). I believe the MAF should account for the change in air density and not need the AIT. The AIT I believe is retarding my timing. The theory I'd like to validate is -

- if the air tempature rises, the amount air is less dense. You have to reduce the fuel pulse to maintain a constant mixture. Alternately, or concurrently (which is what I think the motronic does) you reduce the advance to mitigate the chance of ping/knock with a lean mixture.

I'm really starting to wonder if I should put a choke on the AIT sensor to force the car to see a constant air temp. I've run the AIT unplugged which generates a CE light. I suspect this condition causes the motronic to adopt a very conservative timing (retarded) timing position. Retarded timing = low power.

Also, I believe my car, due to the cam, benefits from low speed ignition advance that comes on during cold run. Advanced low speed timing = better power. I'm wondering if I should also consider choking the cold run sensor to a "cold" state to for the ECU advance the ignition. I can counter the rich mixture by adjusting my MAF signal.

Thoughts anyone?

Jeff