What Aftermarket Clutches Are Available?

Swapping OEM Clutches

[A/H] The ‘stock’ single disk clutch will work on the 91-96 cars. But the 91-96 clutch will not work on the 97-98 cars because the main shaft in the transmission doesn’t have long enough splines to engage the second disk (closest to the flywheel). Keep in mind that the ’97+ single disk clutch has the dual mass flywheel which has a different feel (like a lot of gear backlash) and is much heavier.

[MBA – 99/7/15] To install a ’97+ clutch in a ’91-’96 car you also have to use the ’97+ flywheel because the pressure plate mount and bolt pattern has to match.

Centerforce

Centerforce is known for clutches with increased clamping pressure and total load abilities due to dual friction surfaces, spring enhancements, and addition of weights which increase claming pressure.

They will rebuild your NSX core for about $600. Clamping pressure is up 20%, and total load is enhanced 90%. You must have all the parts from your used clutch and ship them, and you must also purchase a new thowout bearing from

 Acura to be installed with the rebuilt clutch.

The NSX rebuild does not include the weighting, so rotational mass of the O.E. clutch is retained. I am not sure that the set-up is as good as some of the totally redesigned aftermarket units from CompTech, but it should be better than stock. Also, it may be the cheapest alternative available.

So save those old clutch cores. It makes life easier when you have a core to ship out and have rebuilt before your old one wears out.

[CMI – 99/4/15] We switched to the Centerforce clutch as I couldn’t get the Comptech to stop shuttering on takeoff (although it held like crazy once engaged). Both of these clutches were designed to eliminate the potential of the stock clutch springs letting go during high speed events.

Comptech PowerGrip Clutch w/ Aluminum Flywheel

[Comptech] Single-disc design that works with 5 or 6-speed transmissions. Lightweight aluminum cover, aluminum flywheel, single disk design, zero chatter, increased clamping force, heavy-duty spring hub will handle in excess of 425 hp. Better clutch feel, with only 5 lb. increase in pedal pressure provides firmer shift. Total clutch package weight, with flywheel: 24 lbs.; Factory weight (’91-96): 34.5 lbs. (’97-98) 43.5 This clutch will do burnouts all day long with 285/35 – 18 tires all day long! $1850 (No core charge required as all parts are new.)

[BC] This sounds great. It looks like Comptech fixed all the weak points of the NSX clutch design (which I have become all to familiar with). $2000 is a fair price if it enhances performance and could last twice as long as a modified stock clutch.

[CMI] I had 24,000 shudder-free miles on my stock 95 NSX clutch (which was far from worn when replaced). When I installed Comptech’s single disk competition clutch, it shudders like crazy… only after it warms up.

[AST – 99/4/6] I replaced my stock 1991 clutch with the Comptech’s single disk clutch and aluminum flywheel assembly in the summer of 1998. When warm, the clutch juddered when pulling away from a standstill unless you carefully let the

 revs fall during engagement. The reduced drivability got on my nerves after a few months  so I called Comptech.

They were aware of the problem and sent me a new clutch disc for free. The old one was a sintered metal racing-type unit and the new one is a regular heavy-duty Sachs disc. Which engages as smooth as butter.

Davis Acura Racing

[DG – 99/10/19] After 4 years of pretty hard use, I finally busted my clutch. It didn’t wear out (at 33,000 miles it still had about half its surface material left); rather, one of the "fingers" that allows one of the plates to engage and disengage cracked inside, leaving me with a functioning single plate clutch, which made it nearly impossible to get into first gear or reverse!

So, I confronted the standard question for a replacement: OEM or aftermarket?

It was a short debate: I’ve never liked the OEM clutch, because I’ve always thought it’s too mushy and does not engage/disengage nearly crisply enough. Hey, every now and then it’s fun to lay a little rubber 😉

I’ve driven the Comptech single plate clutch (in Dave Davis’s car), but I couldn’t deal with the pedal pressure — it felt more than twice as stiff as the OEM clutch. I’ve driven the RM clutch, which requires less effort than the CT but somewhat more than the OEM, and which I like. But, after many hassles trying to get a working exhaust from RM (which took 3 tries and cost me a completely melted rear valance, but that’s another story that I’m just too annoyed to write), I’m no longer a big fan of Randy’s.

As luck would have it, I was sharing my dilemma with Dave Davis after our recent River Run outing, and he mentioned that he was about to enter the aftermarket parts business — and a clutch was going to be his first part. Would I consider waiting a few weeks to be a guinea pig for his first clutch? Heck, why not — I trust Dave and he knows his stuff. And, I know he stands behind his service, and he said he’ll stand behind his parts. While I was at it, he suggested adding a lightweight flywheel too. I did not intend to change the flywheel, but since Dave offered me a good price and he was going to be inside the clutch housing anyway, I said sure.

Okay, okay, enough background. How is the new clutch? In a word: Yowza!!

The engagement/disengagement are absolutely awesome — it’s so much better than the OEM that it’s what I would have designed if I could have done it myself. The clamping pressure is (I’m told) about 50% greater than stock, but the FEEL is about 100% snappier. In fact, it took some getting used to, because it feels more like an on/off switch than the OEM’s "dimmer." On the track yesterday, it was a little tricky adjusting to it (it’s far less forgiving, especially when downshifting, where matching revs with deft heal-and-toeing becomes critical), but by my third session, I was loving it. On Pocono’s tunnel turn and long straight, I felt like I was losing NO momentum when I blasted from 2nd to 3rd and then 4th — each gear was there NOW with no slop, no hesitation. I managed a couple runs to 138, and I think a few of those clicks were due to the clutch.

As for the flywheel, I’m not sure I get it: it does sound cool when starting up, but I just don’t see a huge difference in the way the clutch and gearbox behave. As mentioned above, it seems like it becomes a little more critical to match revs with a throttle blip when downshifting because the revs drop more quickly than with the OEM flywheel, but what does this buy me in performance? Maybe once I get skilled with it, this will translate to quicker downshifts. Maybe this is something I’ll figure out after having it a while, but right now, I just don’t see the bang-for-the buck of other mods I’ve done. Maybe I’m just not enough of an afficianado to appreciate it…

On the street, the clutch is fabulous — it makes the car feel much more immediate, more crisp, more connected. The pedal pressure is only about 25% greater than OEM, and only in the middle of pedal travel; after a few minutes, you forget about the greater effort. The hook-up is complete, immediate and awesome — no problem laying big patches of rubber when accelerating from a standstill, and catching second is a breeze if you are so inclined. Neither of these jollies was available to me with the OEM clutch.

As far as the technical stuff behind these toys (specs and the like), I encourage anyone who wants more info to contact Dave directly at davisacura@aol.com.

For a guy who bought his NSX stock and pledged to keep it that way, I’ve certainly thrown that idea out the window. But, I love the way my car performs now — I’ve fixed all the most glaring problems with the original (short gears, Dali sway bars, RM exhaust, RM pads, better brake cooling, Davis clutch, Smartenna [!]). And, I’m delighted that we now have another aftermarket parts vendor to turn to.

RM Racing

[CA] Picked up the NSX from David McDavid Acura this morning. The service advisor wanted to ride along, I started it up, it idled nicely.  I released the clutch and it died on me… damn!…*very* sensitive clutch, fired it back up and slooooowly released the clutch and we moved forward, the clutch is very smooth, but like I said sensitive, the new synchros meshed smoothly, shifted like a 97/98 NSX. Took it up to 35 or so just t get the feel of the new clutch and shifted to 2nd, checked the oil pressure and water temp, all normal, and then shut the TCS off and floored it…WOW! What a difference, the clutch grabbed immediately, with definate authority as if to say "lets go NOW!" I took it to redline and shifted to 3rd, smooth consistent power all the way up, can definitely feel more pull. Looked over at Craig and he had perma-grin, the smile only a surgeon could remove.

Eric, my parts guy has been asking for a ride for a while, so we went back to the dealer doing max acceleration "sprint and drift" all the way to the dealer turn in…. Eric was waiting, and I offered the pilot seat, there was no second asking, he was ready to go, he lets the clutch out, and it dies, I don’t feel so bad.

 The clutch is very good, has a very light feel and is *very* sensitive, but you will  adjust.

[DNG] I stalled once comming of a light. The pedal is actually lighter than before (Bernie said that that should be the case because the original clutch was old and the springs deteriorate (harden?) ), but the clutch engages so much faster and sooner (cause it’s new and has plenty of clutch material dummy)

[MN]  RM Racing Clutch! Night and day difference. When this clutch grabs, it really grabs! You can roast the back tires effortlessly with the stock engine.

[STH] I think the RM clutch is a great clutch for the street. It is better than Comptech’s which has a significantly harder pedal (my left calf is already twice the size of my right ever since I put that heavy duty clutch in my M3) and it is better than the MM because it does not chatter at all. These comments are from experience, not speculation.

[ME] Two huge thumbs up to Randy at RM Racing…I was debating for a few months on what type of clutch to put in my NSX, stock or aftermarket. I had built a relationship over the phone with Randy and felt real comfortable and he set me up with one. I just put his clutch and lighter fly wheel in my NSX, and boy what a major difference over the stock clutch of other NSX’s that I had drove. It is still in its seating process since it takes about 500 miles they say, but this thing hooks up so strong. I had noticed and maybe it is just me, but the cars acceleration is much faster. If anyone is interested in doing a clutch job soon, I highly recommend the RM setup. YOU WILL NOT BE DISAPPOINTED.

[SA – 99/7/15] This is regarding my new RM Racing clutch that was installed about 6 weeks ago.

The RM Racing clutch is a great clutch. The grab is sure and the pedal pressure is not heavy. But, after a couple days, I did start getting some clutch shudder. It occurs when engaging 1st at low RPMs (under 1500). The pedal throbs a bit and then the sudder stops once the clutch is fully engaged.

For the RM clutch, I found that by modifying how I engage the clutch I can eliminate it most of the time. You can either do a very low RPM engage (like under 800 RPM) while trying to get to fully engagement quickly (and stay off the thottle while you engage). This a very casual way to launch. You wait until your clutch is hooked up then you can hammer it if you want without burning clutch material.

The second way is to blip the throttle to about 1500 RPM and engage the clutch as the revs drop. Again, try to engage the clutch quickly without stalling.

I have the light weight flywheel and I found that both these techniques gets you engaged quickly, while minimizing clutch wear.

The worst situation is trying to maintain a very slow speed while going slightly uphill (like waiting on a freeway entrance ramp). For this situation, I let a few car lengths open up in front of me, engage, go slow, then disengage and wait. If you ride the clutch, the shudder is very noticable and you start hearing your linkage clunking.

Dali Racing

[MBA – 2000/2/3] I just installed Dali’s new performance clutch and the thing is awesome. I have never installed a clutch in an NSX that was so smooth, save maybe for a late model single disc. It has zero chatter- up or down- and does not have too much travel. It hooks up NOW, and does so seamlessly. My car has #2 Gruppe M Super Charger installed, and they get on great together. I would use no other clutch. Strong words, stronger clutch.

Motor Mail

[FB] Our hi performance clutch kit is compound of the fllowing parts:

one new competition dual discs clutch release

 two new competition clutch disc

 one new ergal or tytanium light and strong flywheell

 one steel plate 

 6 stell bolts 

 one hidraulic conversion kit ( to modify the release system )

 two metal clutch line with connections

 one release bearing

 All the parts are new, Not Core, are available immediatly and they cost :

 ergal kit : 3.100.000 ( with all the parts mentioned ) about 1774 us$

 titanium kit : £ 3.500.000 ( with all the parts mentioned ) about 2003 us$

The shipment cost are 130$ for the ups ( door to door three days )

The kit improve substantially the nsx performance thanks to it lighter weight ( 6.5 kg for the ergal) it also improve the guidablety , and you’ll never have skid problems, having also a very good modulability.

Our best advise is to utilize the ergal kit ( installation is easy like oem ) , all the parts are fully balanced up to 10.000 rpm and fully tested in our races cars. ( EUROPEAN NSX TROPHY WINNER)

If you have anu kind of questions, about the clutch or any other parts, feel free to email us, private or throught the list.

Thanks and sorry for my english

Lightweight Flywheels

What are the advantages and disadvantages?

[HS] ADVANTAGES: Quicker reving engine… Easier downshifts. DISADVANTAGES: Higher clutch wear (requires more slip to pull away from a dead stop)… Revs drop faster during upsifts (possible slower acceleration)… Harder to start on a hill.

Comptech Lightweight Flywheel

[Comptech] The Comptech Lightweight Aluminum Flywheel for your NSX is designed to reduce mass and weight, resulting in improved action and efficiency. Less energy required for your clutch to operate means more horsepower for you to take advantage of!

Dali Racing / Motormail Lightweight Flywheel

[MJ] You have slightly less inertia to help keep the engine going. Remember that the NSX is a production car with a few compromises – like being able to run on regular – the NSX has a heavier flywheel than *absolutely* necessary to keep the engine going. It has to be able to be driven by someone with no coordination as well as all the fangio’s out there. The car will feel like it has less torque off the line, but wait till it is engaged…..ZOOOOM!

The only downside of the lite fly is that (like the close ratio gears or the 4.235 R&P) that the car did not come with them from the factory and you have to buy one yourself. They are made by JUN Racing in Japan, a quality aftermarket parts company. I can get them for you too if you want one.

RM Racing Lightweight Flywheel

[RM] I have the new Light Weight Flywheel installed and its very cool. With the car in neutral and a blip of the throttle the rpm’s zing up. Driving took an hour or so to get use to. Shifting from gear to gear is much smoother, you lose a lot of the jolt when the clutch engages. Idle is as it always has been. Most noted change is when exiting a corner 2nd gear then punching it, the engine winds up much sooner than before. The lightweight flywheel is 9 lbs. I put the stock flywheel on the ups scale for a weigh in of 17.2 lbs.

This is the Ultra Light Weight unit, constructed of one piece forged chrome moly and has large cut outs around the outer edge (like a bike sprocket ). Price will be $570.00 less the e-mail list discount of 10% ($517.50)

[JPA] I recently had a light weight flywheel installed (utralight flywheel from RM Racing).

I have not noticed any change in idle at all, certainly *no* rough idle. The revs may drop *slightly* faster during upshifts. IMO, this is not a problem and it’s subtle, and it’s *very* easy to get used to.

I live in a very hilly area, and I have no increased difficulty starting on an incline, nor do I notice a need to slip the clutch more to pull away from a dead start. If anything, I notice an opposite effect, the car is much easier to launch. But I changed more than the flywheel, so it’s not a totally fair comparison. I also did short gears and R type R&P. So you’d expect the lower gears to make it easier to get off the line.

With the current set up the car is significantly easier to drive than the stock set up (not to say that the stock set up is bad). This difference is not subtle; it’s a big overall improvement in the car’s demeanor. I would suggest the flywheel makes a minimal difference, on the plus side. I notice nothing negative with the light weight flywheel (except cost).

If you’ve got the car apart for a clutch/etc already, you might as well do the light weight flywheel since there’s no additional labor cost. OTOH, some might think it’s not worth the combined labor & part cost to do just the flywheel alone.

Product Comparisons

RM Racing / Motor Mail Clutch Story

[STH] Well after many delays, I finally picked up my NSX. I took the car to our favorite East Coast NSX mechanic Bernie at Davis Acura to get Comptech headers, Japanese gears and the Motor Mail lightweight (~2 kg) flywheel / clutch kit installed. There were a *lot* of problems faced along the way, mainly focusing on the Motor Mail clutch kit. The transmission had to come out again due to one of the problems, so I bought the used CTech R&P from Dave Davis and had that put in as well.

When I picked the car up initially, Bernie and Dave warned me before I even drove the car that there was a significant amount of clutch chatter when engaging first gear. I was just so happy to get the car back that I figured I would live with it and hope it went away with a little wearing in. Well, it didn’t. The car would shake a lot when engaging first gear even if I slipped the clutch and applied more throttle. It was absolutely annoying and embarrassing driving the car in stop and go traffic. BUT, the car felt *awesome* once it got going….

Dave Davis was quite impressed and thought it was probably the fastest normally aspirated NSX that he has driven… I would agree wholeheartedly. The throttle response was incredible… it was so much better than stock that I actually thought of just living with the chatter until I hit my first traffic jam. With the constant shaking every time I had to start from a complete stop, I decided to take the car back and have the MM kit removed. I called Randy at RM Racing and asked him to overnight me a clutch. The RM clutch was installed without a hitch… but Bernie could not disengage the clutch completely even with the pedal to the floor. Randy had the company who makes the pressure plates for him overnight another clutch kit (problems with UPS delayed this one), but it finally got to Davis Acura a few days later.

Many thanks to 1. Davis Acura (Bernie, Dave and Glen) for their patience and great service through this ordeal (and for cutting me a break on the labor! ;-). You would not believe the amount of time spent on this car., 2. Randy at RM Racing for standing behind what he sells 100%, and 3. Mark at Dali Racing for trying to speed up Motor Mail.

My thoughts on the MotorMail clutch is that it is the best kit for the NSX *if* they can get the chatter problem out, give full detailed instructions on the installation (a lot of time was wasted due to this), and *learn* the meaning of the word "support". With its current design, there is no way the clutch kit will not chatter since there are no springs at all on the discs. To me, this completely loses the refineness of this car. I have had other cars which had lightweight flywheels and they all had a slight vibration at idle or a slightly lumpy idle… but with this kit, the idle was solid with no additional vibration. This is the first lightweight flywheel that I have installed where I never worried about stalling the car at all… even in second gear rolling along with no throttle, the car felt fine.

Another important note, Motor Mail needs to do a LOT of improvement on customer support before I ever buy stuff from them again. Waiting three months for a clutch kit and then going through all the problems was a frustrating experience. I really do believe that Francesco means well, but just can’t deliver on his promises. The bottomline is that due to Motor Mail lack of directions, shipping an incomplete kit, and absolutely taking what seemed like forever to get me the correct parts, the whole ordeal cost me about **$2000** in additional labor charges.

The RM clutch kit on the other hand is great. A very smooth engagement and effortless driving around… only a slight increase in pedal pressure (I thought that the stock pedal was little too soft anyway) and it clamps on tight. Great kit also…. put a light weight flywheel in this kit and you got even a better one.

Performance