A change in sound when accelerating led me on a search to find out what was going on. Snooping around beneath the S4 revealed this:
Found it! Fortunately Apikol sells just the bushings for the mount so I ordered a pair to replace the failed parts.
It turns out that there are two versions of this bushing so I needed to order both since I did not know at the time which version I have. I’ve documented the part number in case this happens again.
Having had some challenges getting one of the Mamba wastegates to fit and ending up filing it down so it would work, I contacted Mamba to let them know about the fit problem.
They contacted me today to let me know that they had revised the bracket and wanted to know if I would like to have the updated version.
Since I already altered the part I declined to have a new bracket sent, but I’m glad to see they updated the part so it should have better success for others.
After getting my wideband O2 sensor installed I disconnected the electrical signal to the N75 so that I could check the boost pressure that the Mamba wastegates allow with just the preload.
I am glad to see a mostly consistent level of boost being held, but I had set the preload to 12 psi prior to installing the engine in the car so I was expecting to see closer to 12. I’ll next be double checking that the preload is equal between the two Mamba wastegates.
