- Jul 31, 2009
I’m trying to get my car ready to be tuned and I’m having a issue with boosting past spring pressure. My mods list is up to date but the basic run down is a 6062 divided T4, 38mm tial WG’s with the 24# springs, 3 port IR boost solenoid with both the top and bottom wastegate ports hooked up and boost sourced from the compressor cover. The turbo and hot parts are brand new this year with just a little cruise time on them. The gates and pretty much everything else in the engine bay are a few years old with 3,500 miles on them. Everything worked perfect the last time it was on the road in late 2020 and the HX35 and the old hot parts were still on the car. Currently car is spiking to 32ish psi and maybe beyond but I haven’t stayed in it long enough to find out. The wastegates are opening I can hear them and see exhaust soot inside the brand new dump tubes. I have boost leak tested it to 40psi. I have eliminated the boost solenoid and hooked the lines directly to the compressor cover. I have replaced the wastegate diaphrams even though the old ones looked perfect and had no signs of a tear or being pinched. I switched to 5mm vacuum line with this new setup to have a tighter fit on the barbs but just today switched it back to 6mm thinking the wastegates might now be getting enough volume of air to work properly. I have verified the vacuum line routing is correct countless times. None of this has helped with my over boosting issue. Next on the list is to take the WG’s back off and bench test them and possibly lower the spring pressure. I figured I would see if anyone else here had some input on possible causes or something I’m missing before I do that. Could the 38mm WG’s just not be big enough for a 60mm turbo? I wouldn’t think so but I’m not counting it out. Any help is appreciated. I want to have some fun with this thing this year.