Tag Archives: SMFW

BMW 135i/335i Clutch Upgrade for 600HP+: SPEC Stage 3+

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.

SPEC Stage 3+ Clutch

When replacing your clutch, I highly advise that you also replace the factory dual-mass flywheel (DMFW) with a single-mass flywheel (SMFW). The OEM-style DMFW is known to create false knock, causing misfire issues at high power. If you aren’t aiming for more than 600HP, you probably won’t need this SPEC Stage 3+ clutch kit, you’d be better off with the 335is/550i clutch upgrade.

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Best Clutch Upgrade for BMW 135i/335i (335is/550i Clutch)

2017 Update: This 335is/550i clutch setup held up great for 22k hard miles! I have absolutely no complaints. In June I decided to upgrade to MMP Stage 3 turbos and chase 700whp. I knew this clutch setup wouldn’t hold, so I removed it and replaced it with a SPEC Stage 3+ unit.


After turning up the boost on my stock turbos, the factory clutch started to slip. I decided it was time to upgrade so I could enjoy my 135i to it’s full potential. From SPEC to ACT, there are plenty of aftermarket options available. Then I found the 335is/550i clutch upgrade on ECSTuning, so I started to do some research.

This clutch comes factory in the F10 550i, which puts down 443 tq and weighs a whopping 4552 lbs. DINAN doesn’t offer a clutch upgrade for their different stages of 550i’s, so apparently they feel that it is adequate. Their Stage 3 550i puts down 580 tq and they kept the factory clutch. Also, someone on the forums is using this clutch and claims that it is holding at over 620wtq on aftermarket turbos. To me, it sounds like the clutch is severely underrated.

My 135i won’t see more than 500 tq anytime soon. I’d guess that it is currently around 420whp/465wtq, but only weighs 3300 lbs!

I decided to give it a try. Here is my parts list from ECSTuning:
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