Originally Posted by Z Madness
Sean, Have you looked at the MAF by any chance? We are having issues with the MAF reading the correct airflow at higher boost. I don't think fuel is an issue at this point but we are definately having problems with the ECM reading the airflow properly (at>5 psi). Also, have you looked into the tuning of the ECM yourselves or are you working with someone else? Lingenfelter was concerned that they wanted more horsepower out of their system and I suspect they gave up due to problems with safefully increasing the boost. Also, the Leno car only had about 360+ish (I forgot what the actual number was) on their twin turbo so I would suspect they couldn't crank up the boost as well.
I have not looked at the GM V-6 MAF. However, I have dealt with a lot of different MAF's over the years in forced induction cars. Modern MAF's, and intake systems are very finicky. They can be tuned/parts changed around, but sometimes its complicated to figure out those issues.
Some of the problem's may be fundamentally tied to how the STS turbo charger works, blowing across a MAF that generally is only on a negative pressure side. It might require some rethinking for this car.
DI requires some rethinking, I have been interested in DI for a long time, and I enjoy studying it. More power, lower octane. Its really a win, win situation. However on the aftermarket side, it does make things a little more difficult, but if it was easy, everyone would do it. I try and embrace the newer technology and figure it out rather than just go the route of some people, and get rid of it.
As far as the ECU tuning goes. I know people that have access to stuff that a lot of other people might not.