Clutch life...

[krazzyk01]

From what y'all are saying I would agree that it's all driver/usage. As I was saying before. My concern was based on the fact I've never owned a car long enough to need one, yet I've had to replace them in 2nd hand cars I've owned in the past. On top of that, they've all been much older cars.

So basically, all the people I'm seeing in here which are replacing their clutches are due to them "wanting" them upgraded or needed them due to an increase in HP past the limits of the stock set-up. 'Bout right?

[Billy10mm]

Originally Posted by krazzyk01

So basically, all the people I'm seeing in here which are replacing their clutches are due to them "wanting" them upgraded or needed them due to an increase in HP past the limits of the stock set-up. 'Bout right?

And the third and most common reason, is that most of them aren't especially skilled at working a clutch. Properly working a clutch is an especially rare skill. My father and mother have been driving stick shifts since before I was born, and they are terrible at it. One of my brothers learned to drive stick from my father, he's terrible at it.

99% of people who learn to drive stick in this country, learn it from someone who isn't necessarily a car geek/nut, and as such, never bother to deal with rev matching in any way. Worse, is the blatantly wrong and damaging advice some people teach others about clutch use. I have had two friends separately tell me that the best way to keep a car from rolling back on a hill while waiting at a red light is to leave the clutch partially engaged to hold the car in place. I've been in a car with one of them while he stopped on a hill and could smell the clutch for a few minutes after that one.

The first "stick" I owned was a 750cc sport bike. Not matching revs on a bike meant massive driveline jerks that, when leaned over far enough to put your pegs on the deck, could easily result in a loss of traction. So on a bike, you have no choice but to rev match and for me, I naturally moved that habit over to cars. After joining the BMW CCA and starting to go to the track, some instructors/freinds helped me to really get good with my footwork. But again, it's rare, very rare. Strangely, I've been in stick-shift cars with other motorcycle buddies of mine, guys who I know blip their downshifts on two wheels, but none of them properly rev-matched their downshifts in a car. I found that extremely strange.

[X25]

Indeed, as many have stated, how you use the clutch has a lot to do with the life, though we should state here that engines with high low-RPM-torque (like ours) are generally harder on clutches.

- Rev-matching downshifts take a huge load off of the synchros and the clutch. Proper rev-matching should therefore increase the life of clutch.
- If you ever 'ride' the clutch or do high RPM launches (with clutch slip, without the launch control), you're eating up your clutch material.

As a reference, I have done about 10-15 track days, and my clutch is so far holding up just fine. Clutch is a simple wear item, and I'd not be upset if it doesn't last too long. I employ methods (like rev-matching, double-clutching at the street at times, etc.), not to extend the life of the clutch, but to rather keep the transmission safe. Those poor gears.. : )

[Billy10mm]

Originally Posted by X25

Indeed, as many have stated, how you use the clutch has a lot to do with the life, though we should state here that engines with high low-RPM-torque (like ours) are generally harder on clutches.

I have but one point of contention: ... engines with high low-RPM-torque (like ours) can be harder on clutches depending on driver habits. That's how I'd word that.

If you are driving a 4K lb car with a small 4-banger that makes a peak of 100 lb-ft of torque, and I'm driving a 4K lb car with a blown LS3 under the hood, and if you and I both leave a red light and accelerate at the same rate, then, assuming all other things are equal (like rolling resistance of our tires, gear ratios, etc), both of our engines are outputting the exact same amount of torque.

My LS3 is using a much smaller portion of it's available power, but I'm still putting out exactly the same amount of torque as your much smaller motor, that's why we're accelerating at the same rate. Since our output is the same, we are both applying equal amounts of rotational force on our clutches during the slipping period, so clutch wear is theoretically exactly the same as well.

Now ... if you are taking off in a drag-style launch and I am as well, that's a different story. My motor makes more torque and will shave away more of the clutch material, but that's the "driving habit" part. Drive like a normal human being, and the wear should be identical to every other 4K lb car on the road.

Weight is actually a big part of clutch wear. It takes more friction (which means more slipping and more heat) to get a 4K lb car off the line, than a 3K lb car. So if my LS3 is mated to a 3K lb car and your 4-banger is sitting in a 4K lb car and we both leave a red light at the same rate, I actually put less wear to my clutch than you do (again, assuming all other variables are equal including driver actuation of the clutch).

[X25]

Originally Posted by Billy10mm

I have but one point of contention: ... engines with high low-RPM-torque (like ours) can be harder on clutches depending on driver habits. That's how I'd word that.

If you are driving a 4K lb car with a small 4-banger that makes a peak of 100 lb-ft of torque, and I'm driving a 4K lb car with a blown LS3 under the hood, and if you and I both leave a red light and accelerate at the same rate, then, assuming all other things are equal (like rolling resistance of our tires, gear ratios, etc), both of our engines are outputting the exact same amount of torque.

My LS3 is using a much smaller portion of it's available power, but I'm still putting out exactly the same amount of torque as your much smaller motor, that's why we're accelerating at the same rate. Since our output is the same, we are both applying equal amounts of rotational force on our clutches during the slipping period, so clutch wear is theoretically exactly the same as well.

Now ... if you are taking off in a drag-style launch and I am as well, that's a different story. My motor makes more torque and will shave away more of the clutch material, but that's the "driving habit" part. Drive like a normal human being, and the wear should be identical to every other 4K lb car on the road.

Weight is actually a big part of clutch wear. It takes more friction (which means more slipping and more heat) to get a 4K lb car off the line, than a 3K lb car. So if my LS3 is mated to a 3K lb car and your 4-banger is sitting in a 4K lb car and we both leave a red light at the same rate, I actually put less wear to my clutch than you do (again, assuming all other variables are equal including driver actuation of the clutch).

I think you should also add the impact of revs into account. If they're launching with the same thrust, I'd actually think the little 4-banger is abusing its clutch even more. Alas, the 4-banger will launch slower, exerting less torque, and will likely make less damage on the clutch despite marginally higher RPMs. OK, enough theoretical imagination

Right, we should mention the impact of weight on not only the clutch, but the whole driveline. It's a tough job; I'm actually impressed by how stout the driveline on Camaros are, considering the heavy duty job.

My rear differential completely 'opened up' after a few track days, testament to the weight of the car, and how much work it has to do. It has never happened to me on my Corvettes, or other cars that I went to track with; none were nearly as heavy.

[CrystalRedTintcoat]

I didn't have slippage or chattering. I had the pedal go to the floor. 25K miles. About 9 track days. I replaced it with a monster clutch.

[Billy10mm]

Originally Posted by CrystalRedTintcoat

I didn't have slippage or chattering. I had the pedal go to the floor. 25K miles. About 9 track days. I replaced it with a monster clutch.

Yours is admittedly an entirely different issue. I followed those track/clutch threads with interest, as I've been known to take my cars to "private roadways". If I read correctly, a water tester was confirming that there was moisture getting into system which would cause issues as it boiled.

Did the Monster fix your problem outright? I remember that for one person it didn't and he ultimately found the moisture problem which I believe was caused by a bad sealing of the clutch reservoir cap. Thoughts?

[X25]

Originally Posted by Billy10mm

Yours is admittedly an entirely different issue. I followed those track/clutch threads with interest, as I've been known to take my cars to "private roadways". If I read correctly, a water tester was confirming that there was moisture getting into system which would cause issues as it boiled.

Did the Monster fix your problem outright? I remember that for one person it didn't and he ultimately found the moisture problem which I believe was caused by a bad sealing of the clutch reservoir cap. Thoughts?

I think the reservoir cap has a breather by design. Ultimately, we need to frequently bleed our clutches, especially if we are hard on them with track use, etc., to avoid most of these issues, and the method of replacing the fluid in the reservoir only goes so far. I have painstakingly installed a remote clutch bleeder due to this reason.

[krazzyk01]

Thanks for all the input. Once this clutch goes I'll put in the bleeder. With mine still under warranty I don't think I want to open that can of worms just yet.

[Centerforce_Clutches]

As long as your driving style/habits are consistent, you will usually notice when the clutch starts slipping early enough to start saving for that replacement.

[markgws6]

Going to wake up this thread. I'm at about 26000 miles and I am a easy-moderate street driver and an intermediate level driver on the road course with maybe 7-8 full track days in the car. I typically try not to 'slip the clutch' whenever possible. I "hate" with a passion the hill-start feature in our cars.

Car is shifting okay at the moment.
My clutch is engaging way high on the release however. Is there a way to adjust it or am I just ready for a new clutch? It might "slip" a little once fully engaged, but not much yet.

[Camaro_Corvette]

Mine is a little shorter since my friend has been driving these last couple weeks. God he's terrible. He's too used to driving little compact cars with no HP.

[krazzyk01]

Originally Posted by markgws6

Going to wake up this thread. I'm at about 26000 miles and I am a easy-moderate street driver and an intermediate level driver on the road course with maybe 7-8 full track days in the car. I typically try not to 'slip the clutch' whenever possible. I "hate" with a passion the hill-start feature in our cars.

Car is shifting okay at the moment.
My clutch is engaging way high on the release however. Is there a way to adjust it or am I just ready for a new clutch? It might "slip" a little once fully engaged, but not much yet.

It has been a while since I've looked at this thread. I just recently rolled 51,000 miles on my baby and the clutch seems to be doing just fine. There's other issues GM won't help with in the rear axle but that's another issue.

I noticed part of what I was thinking was a clutch issue is really a crappy set of tires just not gripping. New F1's go on tomorrow and then I'll be able to tell. The Michelin AS3's that are on the back right now are God awful. Tried the BFG AS as well and they're not much better. In third gear rolling about 40 if I floor it I'll get sideways if I want and going straight just means you can feel them spinning.
Not turning this into a tire thing, I'm just saying I think earlier I was probably mistaking crappy tires for clutch slip. Silly me. lol

As far as the Hill Control nonsense. Get rid of it. All you have to do is replace the sensor under the center counsel with the one for a V6 Automatic trans model and you're done. All gone. Search the threads and there's a really good step by step on what you need and how to. Probably the 2nd mod I did and should've been the first. You'll be very glad you did it.

Concerning you peddle height. Have you ever tried bleeding the system? I would assume you have but wanted to start there.

[markgws6]

krazzy -I've tried bleeding/flushing my clutch fluid (and brake fluid) several times with dot4. Shifts are typically smoother after doing so but my clutch engagement seems to be at about the same place (high). I have brand new MPSS tires on the rear, so for me it's not tire slippage. They are really sticky on the street (unless I do a burnout). :-)
I guess the removal of the hill assist 'feature' belongs on another thread...but thanks.