Alright Im planning on upgrading with a cam head package, headers and FAST 90/90. Hoping to put somewhere around 400-420 to the wheel. Anyway that being said, Im curious as to what I should do about a clutch. The car currently has 90K on it. Havent noticed any sign of slipping to this point but Id rather not wait until it goes to replace it. Thanks.

 

Anyone have any thoughts on this......

 

I would definatly replace it. I have a 2000 FRC and i put a 100 shot of NOS to it and smoked the clutch. I also have an exhaust and ram air intake. I think with those kind of mods you will replace one sooner or later. I did it myself at my shop and it was definatly a pain in the ***. I replaced it with one of the Ram clutches you can find on Ebay. That and a centerforce flywheel. I couldnt be happier. It is a little sticky at first. Some chatter. But then when you get used to it you will love it.

 

it didn't take long after my H/C for my clutch to start failing. I had the traditional stuck on the floor pedal. It seemed to work ok and then you really push it and the thing would stick to the floor. I had to go back and replace it. I was sorry I didnt do it right away because it costs me more in the end (I didnt listen when everyone told me it would fail).

I now run the tex clutch with aluminum flywheel. although I don't recommend the aluminum flywheel for everyone it does have it place.

 

If you dont plan on making more than 500 HP for awhile, you could go with a LS7 clutch.

 

I just did a head/cam swap that gave me the HP that you are looking for. I haven't dyno'd it, but it should have around 420 RWHP. My mechanic, who is a vette expert, told me to just keep my clutch til it dies. He's done several cars and seen the clutches last 3 or 4 years on some. My car has 42,000 miles....it's a 2000, so I'm hoping it last me a little while longer. Your car with 90K miles might be a different story.

Juan

 

Since I am contemplating an aluminum flywheel, I am curious if you can elaborate. Is it because of the startup from a dead stop?

 

I too have the stock clutch in my car, it dynoed 540 RWHP.

 

It really depends on your driving and what you like to do. Traditionally 1/4 mile cars benefit more from the steel and road racing cars benefit more from the aluminum. This is all because of stored energy. Road Racing cars will always be shifting and it is easier to shift and match revs with the aluminum because it spins so easily. 1/4 mile guys will use the stored energy of the steel flywheel to launch and also when they go to shift the rpms will not drop off as quickly keeping them in the rpm zone.

If we compare the 2 really it comes down to weight. The aluminum is lighter thus making it quicker to rev, but quicker to rev also means that it will be quicker to fall off thus it has less stored energy. I believe this is the reason it is harder to start with an aluminum clutch. Most people are use to giving alittle gas and letting the clutch out. Well since the aluminum flywheel is not storing as much energy when you go to let the clutch out the revs are dropping quicker thus cauisng you to stall or buck.

The steel will take longer to rev up, but once it is there it will retain the energy longer. For a 1/4 mile guy who cares how long to rev up they are launching at 4-5K already. The flywheel is already spinning. Release the clutch and all that stored energy is now transferred to the rear wheels thus giving you a better launch. This makes sense to why it is easier to take off from a stop with a steel flywheel because the energy is not lost. Also now when they shift down the track the rpms are not falling off as quickly so they are in the power band longer.

Of course there are other factors that play into the whole game. Weight although seems like a disadvantage could be an advantage for the 1/4 mile people because of the energy stored, but at what point does the weight cost you in ETs? The heavier steel flywheel has to put more of a strain on your other drive train components - how much who knows? Having all that energy stored with the steel one is great unless your tires dont hook then maybe it is not so great.

Oh and one more thing. I did read that some 1/4 mile guys that run below 10 seconds like the aluminum because it is easier to control launch since there is less stored energy hitting the rear wheels and it is easier on parts because there is not this jolt to the whole car.

does it make sense now

 

That's what I figured you meant. You didn't happen to weigh the Tex before install, did you?

 

I can weigh one for you tomorrow if you like

 

Does it have the "stick to the floor" problem? My stocker doesn't slip at all but it suffers from the STTF problem when I take it to the higher rev range and shift to the next higher or lower gear. I have about 420whp.

 

Just a general note on clutch holding power, that's always a good reminder... Speaking of hp or RWHP numbers when talking about a clutch is sorta meaningless. Torque is the correct measurement of "how much a clutch can take". Since a cam/headers on an N/A typically doesn't add a TON of torque, it's not as hard on a clutch. You may shift the torque peak up in the rev band, which is going to give you a lot more HP (remember hp is just a math problem of torque, and rpm), but unless you have *greatly* increased the torque output, it's not going to affect it much.

Things like FI, or N20, greatly increase the torque output and will exceed the holding power (the cf of the disc and/or clamp load of the plate) of a stock clutch.

In your case though, with 90k, and adding some more torque, I'd replace it.

 

Dont get a SPEC, I just did for my VR4 and after only 500 miles it seems slippery and doesent ingage crisply like I want.

 

That would be great. I am also trying to get weights on the new Fidanza setup with the kevlar disc.

 

we only had Tex clutch with the steel flywheel in stock. The weight of the whole kit was 58 lbs. I am guessing that they aluminum flywheel is 7 or so pounds lighter so that would be 51 pounds for that setup.

 

Thanks, that's actually heavier than I expected and heavier than stock.

 

I thought the same thing, but hey it works great something that you can't say for the OEM.

 

I had the STTF problem with my stock clutch with H/C only. Once that motor dropped a valve I built the 402 and with 517/490 decided to go with a SPEC 3. The clutch was great for handling the power but driveability was a bit of an issue due to the chatter.

I recently switched it out with SPEC's new 2+. This clutch is awesome. It feels like stock, does not slip or chatter.