why no boost? turbo experts welcome please

Are your RPM's above 2500 when you are driving, and are you pushing the car hard enough? Turbos will only make boost under load, they will not make boost at part throttle, or at low rpms. Also check your boost gauge, make sure its hooked up as close to the manifold as you can be. As for the turbo, make sure the actuator holds the wastegate tightly closed. If it leaks at all you will get no boost.

Dr.

Yup, definately check the wastegate actuator very carefully. That's what comes to my mind first. You might also check to see if the turbo spins freely... I locked up a turbo once, but it was very obvious because I was at full boost when it happen.

Most other possibilities cause overboost.

The wastegate actuator has an internal spring to hold the wastegate closed, which builds boost. The natural position is closed. If the wastegate fails, it will normally get a hole in the diaphram, maybe causing an overboost condition. Applying pressure to the actuator would only open the wastegate if everything is working correctly. You could try sucking on a vacuum line connected to the actuator. It should seal. However, not sealing would cause the opposite problem.

You may have to pull the turbo to get a better look at the actuator. There should be at least 1/8" preload of the actuator on the arm. Though it feels secure, there may be some play on the arm. Other causes could be boost leaks after the turbo or huge exhaust leaks. Are you using a VAM or other air meter?

What form of boost controller are you using? Also if i remember right, the clocking of the turbo shouldn't really affect the waste gate arm. Is it at some weird angle? It should be practically straight

Dr.