Here is my problem. I purchased my car with a modified std plenum (throttle body cut and welded to the front), as im upgrading to a larger turbo and goin to push around 20psi shortly. I dint want any detonation problems caused by uneven distribution of air between cylinders that the plenum would (probably) cause.So over the long w.e i fited a Chinese GReddy plenum. The previous plenum setup ran perfect with my power fc (tuned for std turbo,injectors,afm,12psi) and even on the std ecu. With the new plenum fitted car fired up first crank,idle was abit rough though expected, when for a drive and there is a masive loss of power. Car is struggling to rev through the range, as if a shit load of timing has been pulled out (similar to R&R) but worse. Do you think it could throw the tune out because of the shorter runners and overall volume change ect of the new plenum, or have i done somthing wrong (followed the wright up in DIY). Like a big vac leak, all looms are pluged in,i used gsket goo between head and plenum but also reused factoty metal gasket. Holds boost fine. Also plugged std ecu back in idles perfect and drove allot better but not 100%.
Sorry for essay. What do you guys think.