FAQ regarding UUC & Spec clutch kits - The Unofficial BMW M5 Messageboard (m5board.com)

marcvip · 15th February 2005, 03:45

Note by Admin: this particular post contains a lot of plain wrong and incomplete information - however this is addressed further down in this thread

as we know UUC buys the 11" clutch kit they sell from SPEC and charges double from their garage... I personally know 2 Porsche street/race car owners doing 9 seconds on the quarter mile who swear by SPEC clutches.....

http://www.c2turbo.com/forums/showt...86&page=1&pp=15

Here is good information from SPEC as they never had a chance to respond;

We do not sell our non-self-adjusting billet unit to UUC so they have no experience with it. They purchase our old modified self adjusting units still. Their 11in performance units they buy from us, too, but are marketing them under their name, so they cannot acknowledge that. They want to use the 11in unit b/c no one else is, and so they can sell you a flywheel (won’t work without it). But, as the manufacturer, I recommend the 9.5 unit b/c it is easier on the engine and driveline, more cost-effective, and not relabeled and modified stock stuff.
Our billet clutch kit is made here from scratch like I said before. It has none of the characteristics listed by UUC.

It is NOT a modified stocker- does not have a SAC system at all.
This unit is non-self-adjusting, billet (as opposed to the stock cast UUC is selling you) for extremely strong wear and is the ONLY M5 clutch that is SFI certified, which is why the race teams are going to them.
The pedal effort remains stock, even though the pressure per square inch clamp load exceeds that of the 11in unit UUC is trying to sell you.
Why pay all that money for a stock 850Ci clutch kit when you can have our billet unit? You can use our billet clutch with a factory dual mass OR with our billet aluminum rebuildable flywheel, so you have options.
All of our units when used with a single mass flywheel have sprung hub discs

If you want no rattle at all, the ONLY option is staying with your factory dual mass. We have a core program where you can purchase a resurfaced dual mass from us and send your old one in for a core credit. Like I said before, our billet pressure plate will also bolt right on to the factory dual mass.

UUC has never seen our billet pressure plate. He knows we have developed one, and is not happy we won’t sell it to him.!

Other response;

The “vibration” he is speaking of is clutch chatter. The st3 will chatter for 500 miles and a little after. That is normal, as the regular st3 is more aggressive and takes some mileage to smooth out.
Firstly, if the clutch is slipping immediately, he did not have it through the break in period. The st2 has a 500 mile break-in period. During that period, it will slip under full throttle. Also, did he resurface his flywheel? These guys do not understand that you HAVE to FOLLOW the instructions that come with the clutch or those symptoms will arise. If the flywheel is not resurfaced, the st2 will not even release (which is why his wouldn’t work the first time) The st2 has to have a perfectly flat flywheel or the pp will not lift high enough to let it go. The instructions also explain the break-in period. If the instructions are followed, we guarantee the clutch will work flawlessly.
The billet is different in that it is stronger, so the clutches will break in quicker. The billet plate also eliminates the low lift of the self adjusting pressure plate, so release issues are gone completely. The billet plate operates the same at 10K rpms as it does at 4K, so it is very easy on the trans syncros when speedshifting. The billet clutches will last considerably longer, too, simply b/c the clutch surface is billet 1050 high carbon steel instead of cast.
Most M5 clutch problems, regardless of the manufacturer, are because people don’t resurface the dual mass. (Which is why we offer the service on the flywheel core at our cost) The dealer tells people they can’t resurface them so they’ll buy another one, and general mechanics don’t have the proper equipment to resurface them. So what ends up happening is nothing gets done at all. You won’t find a BMW customer that has our flywheel having slippage or release problems, simply b/c the problem area is eliminated.
So, as with any M5 clutch, the flywheel MUST be replaced or resurfaced or the clutches will slip longer than normal and wear prematurely.

alibo70 · 15th February 2005, 04:02

That is great news, thanks for sharing with us. Spec seems to be a very reputable company. Some board members have decided to go with them, and hope they have good results. The majority of us can use a cheaper solution. I am certain I will go the Spec route as well. The UCC option just doesn't sound cost effective, who knows how much they're making on it.

mottati · 15th February 2005, 04:26

have you gotten yours installed yet? you got the dealer to do it in place of the factory clutch, right (different thread)?
Mike

M5Kid · 15th February 2005, 04:46

We carry the SPEC clutch kit for the M5. I feel that it is a great route for those who are not satisfied with the stock clutch, or who would rather put their money into an aftermarket unit after their stock clutch fails. Plus, the pricing can't be beat.

Please don't hesitate to ask any questions regarding the SPEC kit, and I'm very happy to see the positive comments on this deserving item.

Travis

CSBM5 · 15th February 2005, 05:16

It's interesting to note that the lack of thermal capacity for very hard driving is not even addressed. Clamping pressure has no impact on thermal capacity. Sure you can build a 9 5/8" clutch pressure plate with enough clamping force to hold 1000 lb-ft, but that is irrelevant to thermal capacity needed to transfer major power while slipping the clutch such as at the strip. There is only one way to obtain that capability and still be a viable, streetable option...American car makers figured it out long ago as Lscman attests to.

It seems clear to me that whoever wrote that reply has little or no serious engineering knowledge...they appear to be a salesperson motivated by commissions.

dmz · 15th February 2005, 05:20

I wonder if adding a transmission cooler like most high performance have, would help the heat dispation of a stronger 9 5/8 clutch.

CSBM5 · 15th February 2005, 05:23

Quote:

Originally Posted by dmz

I wonder if adding a transmission cooler like most high performance have, would help the heat dispation of a stronger 9 5/8 clutch.

It would have no effect. The thermal capacity issue is in the disc itself. It is simply too small and has too small of a swept area.

MT JTN · 15th February 2005, 06:35

I'd like to see what Rob from UUC has to say in response to this post.

-Matthew

alibo70 · 15th February 2005, 06:39

Lets not forget that one of the main problems was the SAC mechanism failing. SPEC claims that has been completely removed. The UCC option may be better, but at what cost, and 11 inches is more than likely overkill for alot us out there. A properly designed 9 5/8 clutch should be capable of being ran hard. If there is greater clamping pressure meaning it engages properly that means it not gonna slip. So why would any heat be generated. SPEC is based out of Alabama and have great tech support, and are quite familiar with our cars. They also offer a good warranty on their products as well. This is what SPEC is in business for and thats what they specialize in clutches. If they made crappy products, they would be long out of business. Why would Beastpower sell their products? Maybe we can hear Rob's and Lscman's side on this.

Need4Spd · 15th February 2005, 09:12

Just looked at the BP site about Spec clutch kits and there doesn't seem to be any info about which one is most suitable for street use as among Stage 1, 2, 3, etc. Which one should we be looking at?