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Science of Speed twin carbon clutch review

E-Nough Logic

E-Nough Logic

Experienced Member
Joined
10 August 2010
Messages
633
I ordered my twin carbon a few months ago from SOS amongst a few other items and just wanted to give my input on the experience. I was so impressed with the clutch i had to give a review. The clutch took a couple months to get as it was special order. I installed this on my stock 3.0l for now. I rebuilt the trans which was a first for me, and wanted to make sure everything was good before i installed the turbo kit and brought it to the tuner. I've got about 1500 miles on it so far.

The good:
-Very good directions and labeling for easy installation. Every plate is marked and colored
-The clutch is plug and play no changes need to be made. It uses the stock slave cylinder, no hydro TOB needed.
-Installation was very easy, i didn't even have to adjust the clutch pedal, it disengaged perfect right off the bat.
-Chatter isn't bad, it can be heard when stopped but its the sweet sound of holding capacity imo.
-Fair price for a twin carbon, and not much more than the non carbon and non twin clutches available.
-The engagement is almost too good to be true. I've had quite a few clutches in my day, both twins and non twins. This engages like a sprung single but holds twice as much torque. I had my buddy drive the car(he has a 900whp s2000 with a competition twin non carbon) and he can't believe how smooth it was, and it holds 100ftlbs more than his does.

The bad:
-Nothing yet
 
Nice review, how about from a performance perspective?

Notice the car rev faster and speed pick up quicker?
 
Mac Attack said:
Thank you.

Does anybody have a long-term update? Just curious how it holds up after 5k miles or so.

Thanks,

Dave
Click to expand...

I've put around 10K miles on my twin carbon clutch all on a new 3.2 engine with intercooled SOS supercharger making around 420rwhp and 317rwtq. No problems. The clutch drives exactly like it did when I got the car back from SOS. Best clutch I've owned.

I've had the single disk RPS (the worst -- heavy and on/off) a stock clutch (good but no holding power) and a Comptech (good but fragile).
 
cptnsx said:
I've put around 10K miles on my twin carbon clutch all on a new 3.2 engine with intercooled SOS supercharger making around 420rwhp and 317rwtq. No problems. The clutch drives exactly like it did when I got the car back from SOS. Best clutch I've owned.
Click to expand...

My experience is exactly as above except that my car makes 666 RWHP and 517 lb/ft of torque. :smile:

Buy this clutch immediately, you will not be disappointed!
 
cptnsx said:
Got around 15k now. Still the same. I do not baby my car. I do at least four to five WOT 3rd gear runs every time I drive my car.
Click to expand...

That's encouraging. My first one failed (started slipping) at 7K miles and upon return to the manufacturer, it was determined that there was a defect from the factory.

Unfortunately the second one is beginning to slip after 8K miles but I do have a leaky slave cylinder hose pending replacement. Just waiting on the hose and the damper delete hose to arrive. Hopefully that will cure the issue. If not perhaps RPS screwed up on the second one. I know there are quite a few of these clutches out there and I've never heard of any issues. Hopefully just a little run of bad luck. The rest of the TT setup has been bulletproof for the last 15K miles.
 
I know there are some folks with these on their boosted NSX's that have had problems. But they haven't posted their problems for whatever reason :confused:

From the vendors/manufacturers standpoint, there is always the possibility it was installed incorrectly. Then the finger-pointing starts and everyone gets upset....

It was a difficult decision to buy this clutch over the Exedy twin carbon that is annoying but proven, but I took the chance. I have the "updated" one by RPS with the all-carbon friction liners. Hopefully I can get it installed this Winter during my rebuild.

Hope the slave cylinder hose fixes your slipping issue. Do you have the one with the organic liner?

Dave
 
Sorry - not the hose liner itself, but the clutch material.

The original RPS carbon clutch featured an organic kevlar type (?) friction liner nearest the flywheel. For the newer version that was just recently released in the past 6 months or so, they replaced that liner with another carbon liner. So now, all friction points are carbon-carbon.

I had questioned that previous design feature a couple of times in the past (since it would be the weak link), and was told that it held up fine to very high torque race applications. It's my guess that in street applications where it's slipped a little more, that it didn't work very well.

Dave
 
Good question. I honestly don't know but will check with SoS and get back to you. It was installed exactly 6 months ago though so that puts it at the cusp of the changeover.
 
Just some clarification -- the single organic/Kevlar liner does not lead to accelerated wear. In fact, in clutches we have rebuilt, the organic/Kevlar liner shows the same if not less wear than the carbon-carbon liners. The torque capacity is the sum of all friction liners - the torque capacity of the clutch is not limited by the liner with the lowest coefficient of friction. The dual liner design is very commonly used by clutch manufactures to blend engagement quality and holding capacity.

The new design was changed to all carbon-carbon liners only due to the advent of the flexible drive hub. The torque rating of the clutch is the same as before.

-- Chris
 
Chris I got your email newsletter and on the subject of your clutch improvement for smoother engagement are there any changes in the sound of the clutch?

I've heard some unconfirmed reports that "all" after market clutches do make noise. And that noise to the average audience can sound like the car is about to fall apart.
 
Only noise is with the clutch depressed with the SOS twin. No noise with a single. Heard an Exedy twin and it was pretty noisier than the SOS with the clutch depressed. Neither sounded like the car was falling apart.
 
Update on the clutch. So far around 5k miles and the clutch is driving like day one. I even drove the car through times square in NYC Christmas night and it was fairly comfortable in traffic. Will update at 10k miles.
 
10k mile update. Well more like 11 or 12k. Im making 446whp ~315ftlbs on it now, but driving around everyday at 390whp.

It has still been good for the most part. There was a period of time, about a week or 2, where the clutch had very harsh engagement. It shuttered a lot when moving from a stop. I ended up slipping the clutch a lot and the engagement has been better since. I'm not sure if this is a common problem at all.
 
Everything about the SOS clutch is OEM like and VERY lovable.

THe ONLY "issue" is really getting used to the fact that in engages a little more abruptly towards the end of the pedal travel when it's being released.

In other words it feels more ON/OFF than a gradual engagement.

This does take a while to get used to, but is expected of a clutch that is designed to handle this sorta power.
 
BATMANs said:
Everything about the SOS clutch is OEM like and VERY lovable.

THe ONLY "issue" is really getting used to the fact that in engages a little more abruptly towards the end of the pedal travel when it's being released.

In other words it feels more ON/OFF than a gradual engagement.

This does take a while to get used to, but is expected of a clutch that is designed to handle this sorta power.
Click to expand...

Yeah does take a while to get use to the ON/OFF kinda feel but.... you can get a really good launch on this clutch, it just bites and goes.

Now i'm used to it, it's not so ON/OFF.

Really nice product.

Love the sound when clutch is pressed in. "Because Race Car" :D
 
16k mile update. Everything is still good. It's smoother than ever now. No more shuddering, I'd imagine the warmer temps may be helping.
 

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