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SOS Twin Carbon Clutch - Good for 700 ft-lbs of Torque

25 April 2005
Western PA
Selling a used SOS Twin Carbon Clutch with less than 6k miles and no warranty. This is the updated model with all carbon friction liners sold here:

I used this on my '92 5-speed. I think '97+ models would require the twin spline transmission input shaft and different flywheel bolts (available from SOS). Only the first 2k miles saw up to ~500 ft-lbs of torque. The final 4k miles were back at OEMish 240 ft-lbs. I did not slip this clutch. Due to its grabby, shuddery nature I learned it is best to quickly engage at as low of RPM as possible from a stop and just get the shuddering over with. Comes with throwout bearing, pilot bearing, clutch install tool, and instructions. This does not have the damper delete and hose kit. I bought mine before SOS bundled it into their package. You can buy the damper delete separately for $130 from SOS if you feel you need it:

I'll be honest - I did not like this clutch. But before I get into that, let me list the many positives :biggrin:

Once you are rolling greater than 2 MPH, this clutch is fantastic:
* The pedal pressure is less than 10% stiffer than OEM.
* The flywheel moment of inertia is just right - not too much but not too little.
* For a floating midplate design the carbon discs seem to be quieter than their metallic competitors with the clutch pedal depressed (not NEARLY as bad as the OSG clutch that sounds like cowbells causing pedestrians to stare at you wondering what's wrong with your car).
* This is one of the few clutches that can take 700 ft-lbs of torque.
* This seems to be one of the few carbon clutches that doesn't need a significant warmup to hold all the torque. It grabs even when cold.

Now the bad. :frown:

It briefly shudders when engaging the clutch from a stop. However, my engine mounts are modified OEM (very stiff). Another potential reason was my possibly worn transmission input shaft bearings. In fact, the SOS install instructions recommend replacing the transmission bearings on high-mileage cars when you install the clutch just for this reason. But, I didn't do that when I installed it on my '92 with ~125k miles. I'm pretty sure my 125k mile bearings were worn, and is the reason I just took apart my transmission in the thread below to replace them:

Finally, there's almost no modulation. Due to the carbon nature, it grabs or it doesn't. It can make starting from a stop a bit tricky, and it's best to quickly engage the clutch from as low of RPM as possible. It's really not that bad as most good manual drivers slip clutches as little as possible anyways. The brief shudder from a stop is what killed it for me. It's not good for stop/go driving in my opinion. Of course, if you need this for more than 400 ft-lbs of torque, then there has to be some trade-offs :wink:

The carbon surfaces look good and are shown below. I measured the following carbon thicknesses:
Flywheel: 0.158"
Disc 1: 0.252"
Mid Disc: 0.302"
Disc 2: 0.252"
Floating Disc: 0.093"

I'm asking just $1750 shipped to your door in the continental US via paypal.


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$1675 shipped to your door in the continental US! I think that's the lowest one of these has ever been advertised.

Act now and I'll throw in a brand-new battery ground cable made by Ben (redbird92) for free! This is a great heavy-duty cable that all NSX's should have.

All boxed up and ready to ship....