car had around 16 inches prior to tearing it down and changing the heads out. they are new afr head and also lowered the compression from 11.7 or so to 9.4 or so. Is this why it only idles with 8 inches now? or do I have a vacuum leak. It is on my turbo car and why i lowered the compression on the motor. Having problems with really high egts on it I mean high in or out of boost doesnt matter. I have a wide band on it and it isnt rich or lean so that is out . I have the cam in this retarded about 2 to 4 degrees as anyone who really studied tpi motors knows that retarding the cam with that type intake is good for over 20 hp as it helps scavange air through the intake that doesnt flow well. it worked great on the n/a motor but is it affecting my turbo setup. I am lost and think i need to start with that the vacuum is way lower than it was prior to all this i have done. looking for some engine guru that is familiar with vacuum and why it works as it does. I read that a intake or vacuum leak can cause low or retarded cam timing but it was with the other setup so should change it now.

 

Did you have the turbo on it before the head swap? If not, how does it run? The lack of vacuum would be because you are pushing air in and not drawing it in. Went from a negative air system and are forcing air in. As long as it is running ok, you should be fine. You might want to get your brake booster hooked up to a vacuum pump though so you have the power assist to be able to stop.