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M5 SPEC clutch vs overpriced UUC relabled kit

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.
  1. <LI class=MsoNormal style="COLOR: navy">It is NOT a modified stocker- does not have a SAC system at all. <LI class=MsoNormal style="COLOR: navy">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. <LI class=MsoNormal style="COLOR: navy">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. <LI class=MsoNormal style="COLOR: navy">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.
  2. 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.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

dmz said:
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.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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

-Matthew
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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?
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

With the SPEC clutches, do you still have the oem dual mass flywheel? hence no clatter on idle?
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

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

-Matthew
Actually, I already responded where it was first posted...
http://www.m5board.com/vbulletin/showthread.php?p=513191 ...but as often the case with message board nonsense, the perpetrator usually posts it in as many places as possible.

So here goes again:

With all due respect... I have never seen a larger bunch of misunderstanding and outright fantasy in one post.

Let's dissect:

marcvip said:
as we know UUC buys the 11" clutch kit they sell from SPEC and charges double from their garage...
I think it's pretty obvious we sell SPEC... because in every single one of these posts, I told you we do. Not much of a mystery.

Charging double? HUH? For replacement SPEC clutches, our "regular" price for SPEC parts is a significant double-digit percentage off their website price and certainly cheaper than any independent e-tailer. Now tell me who is charging too much!

I personally know 2 Porsche street/race car owners doing 9 seconds on the quarter mile who swear by SPEC clutches.....
That's great! We swear by them (the non-SAC ones) too! That was never a question, and something I clarified in every post where SPEC has come up.


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

We do not sell our non-self-adjusting billet unit UUC so they have no experience with it. They purchase our old modified self adjusting units still.


Errr... we don't purchase any self-adjusting units from SPEC (or anyone) at all. We did for the E46 applications (same as E39), and they failed (and keep failing) - for the reasons I posted earlier.

If SPEC makes a non-SAC that is not a modified unit for the M5, their chief salesperson had no idea about it just a few days ago.


Their 11in performance units they buy from us, too, but are marketing them under their name, so they cannot acknowledge that.
Again, HUH?

It says we offer SPEC right on the website:





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.
And that's a quote from someone who should lose their job due to BS'ing you to try to make a sale. Please let me know that person's name so I may take up the issue with the owner of SPEC.

We use the 11" unit because it's the right unit for the car, and the clutch size that the gearbox was originally designed to use.

Most of the rest of the quote is also utter nonsense.

- M5 clutches fail because they're too small for the weight, torque, and tire stickiness of the car.

- M5 ORIGINAL clutches fail, this has nothing to do with "resurfacing the dual mass"...

- You cannot safely resurface a dual mass flywheel due to metal filings contaminating the sensitive internal damping mechanism. That's why resurfaced dual mass units fail rapidly. End of story.

- SPEC clutches do not come with break-in instructions.

- M5 racecars? Where?

- SPEC sells plenty of solid-hub clutches... most applications these days simply do not and cannot use them.

- No M5 customers having slipping issues with SPEC OE-size clutches? I guess the people posting exactly that situation here on M5board.com were lying?

It's not too hard to figure out fact from fantasy... this particular fantasy has fairies and unicorns jumping all over the place.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

alibo70 said:
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.
You're missing the point. You have to slip the clutch to drive the car. You can't do a nice and proper hard launch in any manual transmission car without a major amount of clutch slip. If you want a good 60' time and a therefore a good 1/4 mile time, you have to slip it out of the hole. If you want to have a chance against your buddy with his 360 Modena from the light, you will demand that you can properly slip the clutch under a full power launch. ;) You will control the power transfer to the tires with the clutch pedal as much or more so than the throttle in a good launch. With a 9 5/8" clutch with M5 power going through it, this is simply impossible. As I mentioned above...clamping force is irrelevant to the thermal capacity of the clutch -- there is no relation.

If you want a clutch that can take abuse without destructing in short order, you want as large of a thermal capacity as possible. If you go to exotic clutch disc materials in the puny 9 5/8" design to take the heat without failing right away, you are left with a simply awful daily driver...just like if you were using PFC01 pads or any other full race brake pad on the street every day. It may sound appealing, but after you experience it for 1 day, the novelty quickly wears off. Been there, done that.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

marcvip,

The unique UUC clutch assembly is far from a relabeled kit. If it was a relabel job, somebody else would be selling a competitive 11" M5 kit. Obviously certain clutch componentry in the kit is off-the-shelf instead of custom & this is WISE. Adapting a larger clutch from a V12 premium car to fit is ingenious & nobody has beaten UUC to the punch. I find it odd that you criticize the kit for it's custom part (flywheel) and then criticize it again since it shares it's clutch assy with another model. This synergy would seem optimal for the customer.

Relabeled Luk parts &/or kits are, in fact, sold by Sachs, Centerforce, Spec and almost every other leading aftermarket clutch mfr...plus OEM. This applies for E39, Corvette and countless other applications, marques & models. Thank goodness mfrs work together! The EXACT same OEM pressure plate is offered in many so-called performance kits. Some of these relabelers (at least Centerforce & Sachs) rivet on their own organic lining on a disc core, just like any truck/industrial driveline service shop will do "lickety split" for a $50 bill, in most any hick town with a population > 50,000. I guess this makes them different, huh (lol)?

I never heard anyone denigrate the Spec clutch line, especially for Porsche or other applications where the factory clutch setup & sizing is sound. Concerns have been limited to discussing the "undersized M5 clutch issue" (a problem shared by ALL mfrs except one) and two reported out-of-the-box 9-5/8" Spec failures. This is yet another thread pitting E39 suppliers & vendors against each other. This is quite unhealthy for the E39 community, since these relationships are facilitating the release of more products for our cars.

This thread topic offers a hostile twist but says nothing new. Everybody knows Spec produces excellent, affordable clutches for many applications. That said, they do not offer the best combo for every application & duty. Such a claim can not be made by any mfr, incl UUC.

UUC did not upgrade to an oversize 11" clutch assembly in order to sell a custom flywheel. While UCC probably makes a decent profit on their mandatory custom flywheel, such a claim is preposterous in my mind. If the oversize clutch was a big moneymaker with high demand, there would be a bunch of mfrs! There are not (this tells us something), but as a customer I welcome more oversize clutch offerings. An 11" clutch is sorely needed for the 2 ton 400 HP M5. M5 needs a substantially-large clutch like you find in a stock 1975 185 HP Corvette or 1986 205 HP Mustang or 2005 CTS-V.

The concern I have surrounding Spec clutch for M5 specifically relates to two things:

1) continuing to tweak a grossly undersized 9-5/8" design, as Dinan and countless others have done.
2) the fact that two of three reports here about 9-5/8" Spec clutch installs have failed. These may be anomalys and we won't know until more data is available. I am not interested in becoming a datapoint.

These M5 application concerns do not in any way reflect on the Spec company as a whole because these two failures are way "down in the noise" from a statistical perspective. They sell more good product to customers than all but a couple clutch mfrs & they cover a huge number of applications. From what I see, their bad luck is limited to 9-5/8" bolt-in clutch kits for M5 & these stats mirror most other mfrs/suppliers.

The 9-5/8" clutch employed by BMW for the 400 HP M5 is way too small & I predict aftermarket variants will continue to have shortcomings where streetable disc materials are employed. Trying to address an undersized condition with tweaks and more tweaks is like trying to retain the 10" front rotors on a 1986 Mustang GT for road racing by resorting to exotic materials. They are too small & under severe duty, they ignite in flames. Premium materials and design will not suffice.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

alibo70 said:
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.
followed by:

CSBM5 said:
You're missing the point. You have to slip the clutch to drive the car. You can't do a nice and proper hard launch in any manual transmission car without a major amount of clutch slip. If you want a good 60' time and a therefore a good 1/4 mile time, you have to slip it out of the hole. If you want to have a chance against your buddy with his 360 Modena from the light, you will demand that you can properly slip the clutch under a full power launch. ;) You will control the power transfer to the tires with the clutch pedal as much or more so than the throttle in a good launch. With a 9 5/8" clutch with M5 power going through it, this is simply impossible. As I mentioned above...clamping force is irrelevant to the thermal capacity of the clutch -- there is no relation.

If you want a clutch that can take abuse without destructing in short order, you want as large of a thermal capacity as possible. If you go to exotic clutch disc materials in the puny 9 5/8" design to take the heat without failing right away, you are left with a simply awful daily driver...just like if you were using PFC01 pads or any other full race brake pad on the street every day. It may sound appealing, but after you experience it for 1 day, the novelty quickly wears off. Been there, done that.
EXACTLY, CSBM5. Slip is necessary for smooth engagement/operation in a street car...especially a $75K 4dr sedan. You do not want to have to leave the line at 6K RPM & smoke the tires to avoid stalling the car under zero slip. Tiny race clutches provide this agressive ON-OFF function with no modulation capability, so they indeed avoid heat...witness exit launch from NASCAR pits or F1 standing start launches. A good street clutch should have the ability to soak up many seconds of driver-induced slip and still lock up positively the instant when the clutch pedal is totally released. This requires streetable, moderate temp disk materials and generous swept diameter. A luxury car clutch should not involuntarily induce whiplash to driver and occupants, just so the car can have an undersized clutch.
The same argument could be made for tiny brake rotor sizes....lock up the tires into a flat skid and you don't need big rotors to absorb heat. Once again, the tires to the slipping.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

Rob Levinson said:
- M5 clutches fail because they're too small for the weight, torque, and tire stickiness of the car.
While the 275 tires are massive & sticky, you glossed over the excellent 52F/48R weight distribution of the M5. The substantial weight placed on the rear axle adds tremendous strain on the clutch system. This has the same effect as running track drag radials on a ponycar. Compare this to a typical 58F/42R ponycar that comes with a monster clutch from the factory.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

SC'dKellenersM5 said:
PS...i know of a few M5's that are considered race cars...[runs away before being pulled into the nonsense that started this post]
Good point. I got sucked in with the erroneous topic title.....

How any clutch with a failure rate of 2 out of 3 can be talked up (after hearing honest first hand user feedback HERE) is beyond me.

Folks can promote the competitively-priced Spec products as a whole & I'm all for it, but hey, this is the M5board. Spec has some work ahead of them when it comes to addressing a dismal failure rate (2 out of 3 bad) for 9-5/8" E39 M5 clutches installed by forum members. In addition, it will take time to prove this tiny clutch holds up over 70K+ miles. I have heard nothing about the RMA autopsy or whether this QA/QC problem has been licked. This history applies to their recent M5 offerings and overshadows Spec's good reputation for supporting other models. It is unwise to use a broad brush to rate any mfr's products. I feel the same about Dinan, ACS and other market leaders.
 

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Re: M5 SPEC clutch vs overpriced UUC relabled kit

Lscman and others seem to always bring back the case of two people who installed the SPEC clutch and it did not work as expected...please read the response from SPEC....they both did NOT resurface the flywheel and wait for the 500 mile breakin period(stg2 or 3)!;

lscman...I presume you are biased and have a UUC clutch?

from SPEC;

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 .....
 

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Re: M5 SPEC clutch vs UUC relabled kickazz clutch

SC'dKellenersM5 said:
PS...i know of a few M5's that are considered race cars...[runs away before being pulled into the nonsense that started this post]
LOL if anyones going to kill a clutch its going to be you or Abdulla.

Rob / Lscman

Thank you both once again for showing why this is such a great community. The technical knowledge around here never ceases to amaze me.

Sean
 
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