Originally Posted by
lkstaack
Clutch Review
The clutch is performing as I anticipated. On the plus side, the engine revs up quicker when accelerating, the shifts are smooth, and the clutch engages like a boss (I’m waiting on break-in completion before I do a hard launch). Also, it doesn't require a higher RPM when starting in first. On the neutral side, required clutch pedal effort is much greater, almost twice as stiff as stock. I suspect the clamping force is commensurate (it’s a Sachs pressure plate). On the negative side, the clutch chatters, particularly when backing up. I have been told that the chattering will diminish with time. There is a strong clutch smell when I slip the clutch when backing up to minimize the chatter. There is a slight gear box rattle when in neutral with the clutch out, louder when the air conditioning is on. That is to be expected from a light weight flywheel.
Here is some feedback on my UUC 6-Speed clutch and light weight flywheel after 4,000 miles on it. I don't like it and wish I spent the extra money for the stock clutch/flywheel.
The clutch still chatters. It chatters when you start off, when you downshift, and especially when you back up. I usually slip the clutch heavily when backing up to prevent the loud chattering and vibration; however, then you get burnt clutch smell. I guess some people don't mind a chattering clutch; perhaps it reminds them they have a performance car. But it's embarrassing to me and my wife and daughter hate it.
I don't know why the UUC clutch chatters so much. I installed one on my E36 M3 and it didn't chatter at all. I asked a tech from a local BMW speed shop, and he replied that their shop has installed hundreds of UUC clutches on E46's and they all chatter.
I also get the lightweight flywheel rattle. I used UUC's recommendation of a gear oil cocktail to prevent the rattle, and for the most part it works. However, the rattle comes on loud when you are in neutral with the air conditioning on. It is also evident when the transmission is very hot.
One of the advantages of the lightweight flywheel is that rev-matching / double-clutching is much easier now. Which is good, because I have to rev-match almost every time I downshift now to prevent the chatter and heavy vibration that comes with downshifting with the UUC clutch.
The other advantage is that it has much greater clamping force than the stock pressure plate. It holds the extra HP and spins the tires rather than the clutch. However, the extra clamping force is at the expense of a heavier clutch. It's not that bad, but it definitely works out the left leg if you get stuck in rush hour traffic. It is really a pain in stop and go traffic.
So in hind sight, I shouldn't have installed a lightweight flywheel. I should have stayed stock. A stock clutch may not have as much clamping force, but it is much more civilized.
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Lars
2004 BMW 330iZHP: ESS TS-2 Supercharger, Limited Slip Differential, Koni FSD Shocks/Eibach Springs, Sway Barbarians