After “sending it” at 30psi for a couple hundred miles, I developed a misfire. I narrowed it down to cylinder 3, but wasn’t sure if it was plugs, coils, injectors, etc. I swapped all accessories between cylinders, but nothing would follow. That’s when I started to get worried.
Without wasting any more time, I busted out the compression tester. The results were disappointing.
I’m not sure what exactly caused the problem, but adding a tablespoon of oil down the cylinder boosted compression back up. 99% sure it is a cracked ring or a chipped ringland. If I had to guess, the car developed a misfire but I was too greedy and stayed on the throttle while it was a misfiring for a couple pulls. Or maybe it just randomly gave up… I’ll never know why. The logs looked good before the misfire, but I knew I was playing with fire at this power level.
After saving up for a few months, I bought a used motor from a junkyard. It came out of a 2008 335i 6MT with 91,223 miles. The car was hit pretty hard on the driver’s side, so I’m not worried about flood damage or anything like that. It was also modified, so I’m hoping it was taken care of by an enthusiast.
After installing my new fuel system and turning up the boost on my MMP Stage 3 turbos, I started to notice some really bad heat soak in my logs. Guessing that the car is around 600-650whp at 28PSI, I could see that my standard VRSF 7″ Street intercooler was no longer keeping up. It did a great job on my stock turbos, but I needed something a little bigger.
After doing some research, I found the VRSF 7.5″ Race intercooler. Judging by its size and efficiency ratings, it seemed like the perfect intercooler for my power goal of 700whp. I ordered it right away to help cool things down a bit. Four days later it showed up, very nicely packaged.
1/26/18 UPDATE: I ran the MMP turbos at 30psi for about 500 miles and then my motor dropped compression on cylinder #3. I don’t think this was a fault of the MMP turbos. After removing the motor and turbos, I decided to convert to a single turbo setup for various reasons. Watch this video for the full scoop.
On a constant quest for more power, I found myself looking to upgrade from my stock turbos. There are a few different options available, and even some single turbo conversion kits. After doing some research, I was set on a pair of MMP Stage 3 turbos. They offer 700whp capability with OEM fitment and come at a great price. After hearing praises about Mauricio’s customer service at MMP, I decided it was a no-brainer and pulled the trigger!
I opted for fully-optioned MMP Stage 3 turbos which included a 2 year turbo warranty with the bearing treatment. These turbos require larger inlets and outlets, so I opted for MMP’s silicone outlets and aluminum relocation inlets since I already relocated things for aftermarket inlets on my stock turbos. I also ordered the turbo install kit because I wanted fresh o-rings, gaskets, etc.
After reading some DIY N54 turbo install guides, I decided to tackle the job in my garage on jack stands. This would be one of the most involved projects I’ve ever attempted on my own, but I knew it was possible.
If you’ve been following my website, you probably read my detailed post about installing a 335is/550i clutch after my OEM clutch wore out. However, with MMP Stage 3 turbos on the way, I knew the 335is clutch wouldn’t hold as I turned up the boost. With a goal of 700whp, I decided to replace it with a SPEC Stage 3+ clutch and retain my MFactory single mass flywheel.
Since the transmission was going to be removed, I wanted to refresh a few things at the same time. I noticed my shifter developed some side-to-side slop so I decided to upgrade the bushings. The car has almost 120k miles and still has the OEM transmission mounts, so I knew those could be replaced. I’ve also never servied the rear differential and noticed it was seeping a tiny bit of fluid. Might as well replace the rear pinion seal and flush/refill the fluid!