[bulldog_yyc]

Originally Posted by stealth-twntrbo

SPEC is junk, i had one in my Stealth TT and the pressure plate took a shit, spec wouldnt warranty it. Secondly I have 3 friends that have had there Spec clutches fail within 6 months

+1

[jpsimon]

Originally Posted by stealth-twntrbo

SPEC is junk, i had one in my Stealth TT and the pressure plate took a shit, spec wouldnt warranty it. Secondly I have 3 friends that have had there Spec clutches fail within 6 months

And I know even more people with zero issues. We'll see how it goes for me So far it's performing fantastically.

[Tiago@VRSF]

Here's an 11 page long thread of people who have had problems with Spec clutches:

http://forums.evolutionm.net/service...ec-clutch.html

[shifterboy45]

Originally Posted by bimmermans54

Centerforce? Sucks! Wow, I can tell alot of people on here dont do enough to their bmws to upgrade their clutch. AA is coming out with a lightened flywheel, I was holding it in my hand last week. SPEC makes the worlds best clutches, hands down. I had a centerforce in my e36 turbo, and it shattered. Centerforce is used alot in american cars, and they have major issues also. Spec is the most reliable, and stock feeling you can get. They offer different lines, according to what power your going to make. They hold in all the e46 m3s I do, even after I sell them, they are still in the cars, probably 30k+miles after me! So, I am not sure if they offer it yet for our cars, 6 months ago, when I spoke with DAVE Norton, who handles the bmw section, they didnt offer one. Ill find out!

ditto to SPEC -- got a clutch rated @ +600ft/lb torque that is flawless on my mustang. plus ups dropped the clutch at the wrong address and they sent me a replacement no charge .. their C/S is great too

and yes... CenterForce is trash...

[bulldog_yyc]

Originally Posted by tvieira24

Here's an 11 page long thread of people who have had problems with Spec clutches:

http://forums.evolutionm.net/service...ec-clutch.html

wow, and I thought I had it bad

[leeadam]

so who is best to get an uprated clutch for my 330d?

[boostd92]

Originally Posted by tvieira24

Here's an 11 page long thread of people who have had problems with Spec clutches:

http://forums.evolutionm.net/service...ec-clutch.html

FME, for some reason, SPEC clutches seem to shit the bed in transaxles (FWD based transmissions), and hold up much better in a real N-S trans. The F-body guys don't have nearly as much trouble with SPEC as the Evo/MR2/etc guys do.

I had a Spec in my MR2 that lasted a year, and I rev-match when I downshift, I DON'T engine brake, and am very gentle on my clutches. The OEM clutch in my 330 had maybe 2/3rds material left at 75,000 miles.

FWIW, I just verified in the ETK that the M5 and 335 6-speed trans's are at least the same designation - GS6-53BZ (M5). The 335 trans has a "DZ" designation after it... may be shifter location or different tailhousing, but it does look like the transmissions are indeed the same.

The M5 is rated at 383ft/lbs at the fly... so maybe 330wtq, but it also weighs 400lbs more. The real damage to a clutch comes at slipping in order to get a resting object into motion. BMW is known for overengineering, and knowing the beatings M5's were going to take, I'd guess the clutch/trans in a 335 should be good for 400wtq, which is about the upper end of what most people are making, BPU without AI. If you're a smooth driver, don't engine brake, etc, I guess it'd last just fine at that level for at least a year or two if not more.