I bought a Mamba GTX3071R twin entry turbo for my car - and it works well enough, however it comes with a mamba piston wastegate actuator
My 18psi springs is giving me 9psi (and as a 9psi spring, it works really well) - The construction of the actuator is fine, it's a piston actuator not a diaphragm, but the springs are wayyyyy off their ratings. I suspect that maybe there is some issue going on.
This caused me some considerable consternation. I'll be upgrading to the "1.8 bar" springs, and hopefully that should give me a bigger base than 9psi to go from.
I mean, it's not an exact science obviously, but you'd hope to be in the ballpark.
See http://www.mr2oc.com/61-3sgte-turbo/598 ... uator.html for another person this happened to. They also had about half the specified boost.
If anyone else has one of these and has a similar or different experience, I'd like to know.