[cooterhan]

I had my dyno tuning done a while back for pump gas only so far. Made an honest 620 whp running a gt42-02 turbo @ 18lbs with all the supporting mods. Anyway, my problem seems to happen on the street. I have the boost controllers gain set at 13-15 which is about 17-18 lbs of boost under WOT. If I attempt to make a pull say from 1st gear to the top of third, quick shifting and pulling to red line, the turbo only makes about 8-10 lbs of boost. Through these pulls there is no wheel spin through 2nd and 3rd gear. Here's where it gets weird. If I just put it in 3rd and roll into it, the turbo makes 18lbs and pulls real hard. So my question is, why is it not reaching the correct boost level when I go through the gears? If I shift to 4th on a 3rd gear roll that hit 18lbs, it drops back down to 9 psi after I shift from 3rd into 4th gear. This is very strange to me because I have never experienced this before. Any input will be greatly appreciated.

 

[Nick 95 6sp]

It's perfectly normal to make more boost with higher load on the motor, i.e., pulling in 3rd vs 1st. There could still be something more, maybe in the way you have your boost controller set.

I don't have a GT42 6sp so maybe if one of those guys posts you can compare notes.