Clutch and Flywheel Recommendations

My transmission is done being rebuilt and about to be put back in the car. I need to figure out today which clutch and flywheel to put in. The car (1999 c2) is occasionally driven on the street to but more of a fun car and will be raced. Which clutch would fit those needs and take the abuse I am going to give it? And also be somewhat easy for the street. And is the lightweight flywheel recommended and which one? Prices?

lightweight flywheel for sure! aasco makes one for the 3.4L. stock clutch would be fine i think. there's no big power gains in the 996 N/A's other than the supercharger that would require going to a disk that can hold more torque.

I suggest you put in something that will make you a little slower to keep things more interesting in PoC this year

Went with some 6 puck clutch my mechanic got for me with a stock pressure plate.

who did your trans ? what was wrong with it ? and if ya dont mind what was the damage $$$ ? mines very very difficult getting into 2nd gear when cold...no problem when hot

^ i think all of them are like that. if you have a short shifter, it is especially bad.

First gear wasn't working, maybe 10% of the time after grinding it in there, 2nd and reverse were the same Differential was so bad it could be turned by hand when they removed it. When we took out the transmission we noticed that screws had broken off of the pressure plate and put 4 nice holes in the bellhousing. Just the rebuild including the Diff was about 4800, with i think a stronger second. We shipped it out to California Motorsport which is in Arizona. Because of the wrong clutch disc being delivered, I am looking at friday to pick up the car for saturday's event at willow springs.

The Aasco LWF clutch was the only one I could find other than stock for my car.

stay stock

John, I am considering a LWFW and new clutch in the near future. GMG has a clutch/LWFW combo that they guarantee eliminates the chatter isssue. I called them (Fabryce) and never got a return call. Please let us know how you like yours both on the street and track. Thanks, Mark

why do you guys want a lightweight clutch, flywheel for your 911? what is it about the stock setup that u find not good enough?

The stock clutch/flywheel is fine for most applications. I'm going to need to replace mine within the next year or less, depending on how many track days I get to do. With all the mods that I have done, I have probably only increased my hp by 10%. My car only has 35,000 miles on it and the clutch is weak. I plan on eventually adding a supercharger. The stock clutch can not take that kind of an increase in power. I made the mistake with my previous track car of trying to use a clutch that was not rated for the kind of power that my engine was putting out. I increased the hp from 225 to 420. The clutch lasted less than 5,000 miles. I'm not 100% convinced on doing the LWFW yet. I didn't do it on my previous track toy because there are pros/cons to doing it. I would really like to benefit from someone else's experience before I make that decision.

What makes your clutch weak? How do you know that the stock clutch can't handle SC power if you've never had SC on your car before? I'm asking questions because I thought about doing up a lwf and my research told me there is no aftermarket setup that makes the car drive better. It'll either make extra noises and the benefits are nil. This was my research, your results may vary. I had a lightweight flywheel and stiffer clutch on my supercharged S2000. I did it because there were several hardcore track guys with the SC who recommended the clutch and could speak to its longevity even in extreme track conditions. And they were right. Over the next couple of years as more S2000s got supercharged (still a very small number, but for an internet forum, not bad at all), they were right. The ACT/Comptech lwf setup was fantastic. The S2000 stock clutch definitely needs a swap, but I'm thinking the 911 clutch may be beefier from the get-go. And finding someone who knows how to do right with an SC setup... it was tough for me to find a stock car with aftermarket clutch with an owner who seemed to "get it". I'm just trying to remove the BS/hype from this to perhaps bring in the credible people here who've done it v. just throwing things out and hoping it'd stick.

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I went with the stock flywheel.

I bought my car from Chuck Jones. We took his iris blue and my vesuvio 996 out to a deserted road and did a few 0-60 runs with my G-tech. After a few hard runs, his clutch was slipping severly on take-off (with only 33,000 miles on it). With that in mind, I don't do multiple hard launches with the car right now, because I would rather spend my money getting my aero kit painted instead of having to buy a clutch right away. I have done lots of research on superchargers, light weight flywheels, and clutches for my 996 (including here and 6-speed). I just sold a car that had an aftermarket supercharger on it. It has been my experience, that supercharged or highly modified engines creates greater demands on a clutch than a stock engine. I made the mistake once of skimping on buying an adequate clutch for a high performance application. I payed for it by having to replace it after 5,000 miles. I don't plan on doing that again. You mentioned Comptech. I live about 5 miles away from where they were headquartered. I met the owner one night when my K-9 fell through a false ceiling in their shop, while searching for a burglary suspect. He almost got impaled on indy car engine. They built some incredible cars there...especially the supercharged NSXs. I always think twice about messing with an NSX after seeing what Comptech could do to them. I'm not claiming to be an expert on this issue. That is why I'm asking for advice. There are plenty of guys here that know far more about clutches, LWFWs, and superchargers. I would much rather benefit from their advice, than waste my own money making mistakes. If you search here under LWFW, you will find that there is quite a bit of agreement regarding the stock clutch in our cars and the TTs not being up to the task of large horsepower/torque increases. Most of the magazine articles on modded 996/997 tt and (supercharged) NA models show that the builders changed the stock clutch to accomodate the increased power.

What changed my mind about LWFW was the fact that the stock FW absorbs vibrations by being heavier; some of those vibrations also cause RMS failure, resulting in leaks or seepage. John

John, thanks. John (JDS), I had read that the LWFW might be less prone to cause RMS failure because of the reduced rotating mass. You make an interesting point. Unfortunatley, I don't have the expertise to decide one way or the other. I know there are several engineers here. Any opinions? Sorry to hijack your thread John. I would like to make an informed decision when I replace my clutch. Thanks for the input guys.

i think either way you will have a good amount of leap of faith in your aftermarket clutch setup.def sounds like you're comfy with the idea. go for it. i love comptech. i'd love a supercharged by comptech nsx. the sc for the s2000 i had was spot on reliable, ez to install and performed well. if i had that kind of assurance with the SC on a 3.6 unit, i'd do it. but alas i do not have the faith in the porsche engine as i do the f20c honda unit and s54 bmw unit.

I'm yet to find a aftermarket clutch that I'm happy with. The one from GMG looked interesting...but I'm not real keen on doing business with a company that can't return calls. The owner of Comptech and I talked about them doing a supercharger system for the 996 that was actually CA smog legal. I would have been happy to let them use my car as a test mule. Unfortunately, I fear they might have gone out of business. Their location is currently empty and for sale/lease.

yup they're outta business shad was awesome. if comptech made a unit for porsche... i'd look at it.

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I actually have a LWFW, prior to its install I had two RMS failures. No RMS issues since the LWFW. Does anyone else without a LWFW want to tell us why not to get one?

DC, do you recommend the LWFW? Are there any drawbacks for a car that is 95% street and 5% track? Thanks.

try posting your question in the racing/competition sections. those guys probably have more experience.

I wouldnt use a 6-puck disk with a stock pressure plate. Might as well use the stock disk IMO. It is kind of like putting Carillo rods with stock rod bolts, you still have a weak link even though the rods are miles ahead stronger than stock.

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I made my choice about 20 posts ago. But thanks for pointing that out.

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A drawback for me is the noise. It chatters(even more so with the AC on) in neutral while the clutch is released, and gear noise when driving around at low rpms in high gears. So if you plan on picking up chics with your P-Car like Choi does, then I doubt you'd want your car chattering like an International Rig. One of the gains is it revs up through 1rst gear faster than before however, seemingly, with the stock flywheel, once it's reved up it stays reved up. So what I'm saying is the only performance gain I see is accelerating from a dead stop and from very low rpms. As far as heel toeing, it seems easier to heel-toe with the LW flywheel; yet at the same time if you mess up on your heal toe sequence the LWFW is less forgiving, basically because the RPM's drop faster than the stock version.

DC, thanks for your candid response. I really appreciate it. My wife probably wouldn't look kindly on the picking up chicks part. GMG claims that they have a clutch/pressure plate/flywheel combination that eliminates the chatter problem. I do not know if it is only for the 3.6 or for the 3.4 also. I'm sure the gear noise would still be there. I probably won't do this mod, until I can find someone local that is kind enough to take me for a ride in their modified car.

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I wish there were a quiet version, now I'm not saying GMG is lying but most told me that the Aasco LWFW had no chatter, even my installer (until he finished the install). I forgot to mention that "one" of my main reasons for the flywheel swap was that the Aasco was actually cheaper (price wise) than purchasing a brand new stock flywheel. As far as getting a ride you wont "feel" any difference, what you want to do is to get someone to let you drive or at least let you rev the engine a few times. There you will experience the difference.

fletch: with your exhaust I can not imagine the LWFW noise will bother you. I did the Porsche(Sachs) system and love it. Even though you do not track or autox much it is still fun. The greatest advantage of the LWFW is in 1st and 2nd gear. Much faster rev.

i have an aasco LWF with a spring centered spec clutch. i absolutely love it. it doesn't make any noise at all. it takes a little bit of getting used to at first; you have to give the car a little more gas to take off smoothly from a stop. you can shift a lot faster since the RPMs drop quicker between shifts. the car also has a lot more pep now. the spec clutch feels great. it's no more pedal effort than stock. if you get a LWF, just make sure you get a spring centered clutch. this will essentially do what the dual mass flywheel used to do: absorb driveline shock & reduce chatter.

DC, roberga, and insite, thanks for taking the time to post the information, I really appreciate the advice. It sounds like each of you would do the LWFW again, which says a lot. I am hoping to eventually do lots of open track events in this car...I sold my tiptronic 996 and bought this, just so I could have a 6-speed and LSD. I never mind replacing a part on my car, when I can replace it with something that makes it faster or more fun to drive.

My car came equipped with an RS clutch/flywheel. I'm not bothered by the "clattering" sound at idle, but I am bothered by the "chatter" (vibration) that is felt when releasing the pedal during engagement (it's most noticeable when reversing). All in all, I would recommend the upgrade! I suggest looking into adding a crankcase breather/vent while you have it apart.

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i know exactly what you mean. i've found that if i let the car rev a bit more than i would with the stock FW, this chatter does not occur.