135i Single Turbo Cutout Dyno Testing

Hey guys,

Had some spare time today so I decided to do a little dyno testing on the single turbo 135i. As a few know we've been running it through the relatively small factory 135i exhaust system as I like to keep the car quiet on the track. But I've always wondered how much power is being left on the table.

I did a couple runs as the car was raced a couple weeks ago at Shift Sector, 24psi, cutout closed. Then opened the cutout and tested some progressively higher boost levels. At equivalent boost levels the cutout yielded around 15-20whp throughout the curve. And through some tuning I ultimately settled on 27psi tapering to 25psi which kicked in another 15-20whp. This is about as much power as I want to push through the FFTEC 5862 TS kit. Compared to stealth mode we're looking at around 40whp more under most of the curve here with the free flow exhaust and a little more boost. Not too shabby. This along with a little more weight reduction might get that 60-130 down in the mid 5s? We'll find out when it cools down.

Did I mention it was HOT today?