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Discussion Starter · #1 ·
I was digging through my parts left over from my upgrade project at D/A...and I came across my stock friction plate and my stock pressure plate...

I almost thought that Bill gave me back the wrong parts...the clutch is so small that I cannot believe that it is used to transmit power to the rear wheels of our cars...

I have eaten larger hamburgers...

In otherwords...I am glad that I got the larger UUC clutch upgrade...

Two thousand miles of hard driving and not one issue with the SPEC Power Clutch friction plate...

Mark
 

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2,000 miles isn't enough to judge by, let me know how it is after a bunch of drag racing and track events at 50,000 miles. No offence ment, simply to say dont' count your chickens yet. I could hand you a Carrera Gt Clutch and you'd think it's crap too, but would distroy most other clutches. Size dont' matter :)
 

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Jayson,

The Carrera clutch you speak about is not of similar design. It is more like a Formula 1 or motorcycle clutch. It's diameter can not be compared to a conventional single disk clutch found on almost all other cars.

Your same argument can also be made for brakes. An 11" Pep Boys rotor with Hawk HT-10 pads can probably provide better braking torque than low dust, low noise street organics mounted on a 14" Brembo. This does not mean size is not important. What it means is appropriate clutch materials must be selected based upon the temps the clutch surfaces will see.

Assuming similar type of clutch materials is chosen and adequate clamping force isued, size (swept area) means EVERYTHING. This is equally true for brakes and clutches.
 

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Hey Jayson,

How about 36,000 Km's and 150 QM runs. :haha:
 

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Lscman said:
Jayson,

The Carrera clutch you speak about is not of similar design. It is more like a Formula 1 or motorcycle clutch. It's diameter can not be compared to a conventional single disk clutch found on almost all other cars.

Your same argument can also be made for brakes. An 11" Pep Boys rotor with Hawk HT-10 pads can probably provide better braking torque than low dust, low noise street organics mounted on a 14" Brembo. This does not mean size is not important. What it means is appropriate clutch materials must be selected based upon the temps the clutch surfaces will see.

Assuming similar type of clutch materials is chosen and adequate clamping force isued, size (swept area) means EVERYTHING. This is equally true for brakes and clutches.
I understand all of that. Yet my point does hold true, a smaller better material is better than a larger weaker one. Such would be the case with a ceramic clutch of 9 inches being better than, a 11" organic clutch.
 

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MIB said:
Hey Jayson,

How about 36,000 Km's and 150 QM runs. :haha:

Good start, but I still need to see more out of it.
 

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Under typical use, a big brake or clutch with premium organics will often outlast a small brake or clutch with premium race materials.

For example: Go to any road racing track and watch the braking performance of a Porsche 911 or 944T with mild organics on adequately-sized rotors. Compare this to a Mustang with it's marginal rotors...even with the best racey pad compounds.

1)The Porche with premium organics will outbrake the Mustang into any corner.
2) The organic Porsche brakes will last the whole season.
3) The Mustang pads will eat the rotors and cook the bearings and burn the caliper seals up. In many cases, the Mustang brake setup will need rebuilt every 2 days due to excessive heat generated from the race compound pads.

The reason...the Porsche brakes have huge swept area and they are not overdutied. As an added benefit, the organic brakes offer better modulation and they are more consistent under cold use.

This is even true on the road race track, if max organic temps are not exceeded. This is why 11" organic clutches last over 100K mi in many Corvettes. They are big enough to stay cool...well within the optimal operating temp range for organics. I seriously doubt if ANY race disk will last 100K mi without developing puck cracks from fatigue. I think it's premature to assume a small clutch with a race disk will last as long as a large organic under typical use, since ancillary parts like the flywheel, throwout bearing and pressure plate get much hotter than normal. Grease can cook out of the throwout bearing and require replacement. A dual mass can malfunction or develop heat checks and cracks. These OEM components are not designed to withstand such temps.

Choosing race materials does not ensure an undersized brake or clutch system will hold up for lots of miles. All it means is the disk can soak up more heat and maintain torque capacity at extended temps. A tiny clutch with race materials subjects the fragile, stock dual mass flywheel to greatly elevated temps.
 

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:confused3 ouich hiha :eek: :typing: :M5rev: grrrrrrr :wroom: :nono:
 

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LCSMAN is correct.


9" clutch disk - max possible surface = 63.617 sq. in.

11" clutch disk - max possible surface area = 95.033 sq. in.

That's almost 50% more surface area than the 9".

I say "max possible surface area" because I am not deducting the missing area in the center - however that should be about the same for both disks.
 

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Actually....if you measure the inside & outside disk diameters and calculate the difference in surface area, the 11" setup offers just over 50% more swept area than the 9-5/8" unit.

I calculated it myself a while ago, just to double-check mfr claims.
 

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Discussion Starter · #11 ·
Lscman said:
Actually....if you measure the inside & outside disk diameters and calculate the difference in surface area, the 11" setup offers just over 50% more swept area than the 9-5/8" unit.

I calculated it myself a while ago, just to double-check mfr claims.
I still cannot get over how small that stock clutch is...

If more M5 owners would actually see the small size of our clutch...I believe that all this discussion about size would be mute...unless you are actually happy with learning how to use something smaller (adequate, but unexciting).... :hihi:

Mark
 
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