[kobet7]

Hi,

I have been trouble shooting my car for about 3 months now with a tuner and a dedicated performance shop but am having problems that seem to be puzzling everyone.

For background I have a 2016 Subaru BRZ with the Fullblown turbo kit.

Garret 2871R
Intercooler
Oil Cooler
NGK Spark Plugs 0.028" Gap
550C Injectors
AEM 340LPH Pump
Aftermarket Downpipe & Exhaust
Stock Front Pipe with Cat Delete
No Boost Controller (Waiting to fix problem before installing ECBS)
Tial 11 PSI BOV
Tial 7 PSI WG (It was 14 PSI, I will get to that)

I Installed the kit around June and was having no problems. Then about 2-3 months ago I started getting poor performance (hesitation) and backfire while accelerating under boost. This led me to change the spark plugs to the ones mentioned above and changed the MAF sensor with a new one which fixed the hesitation. But now I am left with the car backfiring and misfiring I am assuming because the car will lose power at max boost (14 PSI at the time)

I actually was curious about my WG because I noticed I was hitting 1.83BAR when the car was first installed but was ensured by fullblown that they put a 7PSI spring. Well I pulled the WG to check and come to find out I had a 14 PSI spring the entire time. I changed it to a 7PSi spring which for now solves the problem but I am basically nerfing the car for it to not blow up. I believe I will run into issues when I meet with my tuner for a 8,10,and 12 psi map.

Looking at the logs it looks like I am running lean towards the higher RPM range but it goes back to being normal once I hit a certain RPM which is strange. The log from 11 June shows when the car was running rich (I had a boost leak at the time). The log from Nov 18 is a Revision to the tune that Fullblown gave me back in june to try to fix the new lean issue problem to no avail. With the 14 PSI spring still installed, I will get backfiring and loss of power around 4000RPM which is close to full boost and is running lean. The new log from Nov 27 is after I put the 7PSI WG spring in shows that the car isn't having problems but is running lean.

I had the shop check for vacuum leaks and exhaust leaks and they discovered a few leaks at my piping and blow off valve and fixed them. At this point I am pretty much stumped as to why the car is backfiring and loosing power once I reach a high boost level. I removed and installed the fuel pump multiple times and put an entirely new housing assembly as well. The fuel injectors were removed and there were no visible clogs or damage and the o-rings are still in pristine condition. No fuel is leaking from the port injectors.

It is just strange because even with a 14PSI spring, the car was not running lean and was actually running rich in june but has now became lean.