Hello all, I am new to turbo vehicles and using the forums and google, we were (almost) successfully able to upgrade and intercool my turbo swapped Z. The issue is that it overboosts(boost creep maybe?) consistently in every gear. We bought a new wastegate for it with an 8 psi spring. Boost goes up to 15+(gauge stops at 15). It doesn't hesitate to get their either. When the turbo spools, boost builds a little slow and then shoots up(at this point, the turbo spool is a lot louder) and goes past 8 psi. I bought a new wastegate thinking the other one was damaged with no different results. Car runs fine and pulls hard, I just don't want the boost going that high. It causes it to stutter and pop at anything past 13psi. My goal was 12 psi(I have 330cc injectors and a Begi FMU) I have a boost controller installed but it did this without one installed(line from compressor housing to wastegate and the line was only a few inches long ~7 or so and needless to say, the boost controller is turned down until I figure this out) The car is so great until it hits high rpm and boost and leans out.
The turbo is just a t3/t4 on a l28et so I don't think thats too much for the wastegate considering thats a common turbo upgrade for this motor. I have scoured google and the Z forums and cannot figure it out so I am finally asking for help. The quick question was about the install of my bypass valve. The previous owner installed a bosch type and we kept it in sequence to what it was before the intercooler and turbo upgrade. I had no boost issues with the previous t3 turbo but the compressor wheel seal went out and car was smoking like crazy. Below is a pic. It goes from intercooler pipping(pre-intercooler) back to the turbo. The vacuum line behind throttle plate goes to the FMU and the line from the back of the manifold goes to the Bypass valve, like it was when I got it. Is this correct? Thanks for any help and RTz, is that descriptive enough for you?