bcartman2

we are getting down to the last little bit on the STS z06 build, we just added a second wastegate because it only had a gate on one side and we put 10# springs in both of them. We ran a T off of the original vacuum line to the second gate. the first few runs we were only getting 7lb of boost and then we blew the air-bridge, come to find out it was leaking all along. so we put the STS air-bridge on and went for a ride, wow what a difference, the problem is that it built up to 12lb of boost before I let out of it... what could be causing the overboost, the vacuum lines are all tight and leak free, what else could it be?

thanks
Bill

Paratrooper307

It could be that the springs are stronger than they say. A 2 psi variance from spec isn't something to be alarmed about unless it was still building boost when you let off. Overboosting situations can be caused by inaccurate spring ratings, too small A/R housings/inadequate waste gate flow, boost controller solenoid issues (if equipped) and vacuum line issues. Waste gate placement is important to get sufficient flow. If it's an option, run a lighter spring and see what it does, or combine a lighter waste gate spring with a boost controller to reach your goals.

romandian

if you have boost creep the wastegates are too small or dont open enough. if you have a spike when the turbo is comming in, thats normal without electronics.