what really destroys a clutch
04-27-2005, 01:13 PM
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what really destroys a clutch i went with a spec II clutch with a stock resurfaced flywheel. my car has a lid and a cutout, and nothing more performance-wise; it will probably stay that way until i sell the car. in addition, my car has never seen the track, nor will it ever, and i don't drive it very hard on the street (occasionally, of course). i can't decide if i should have gotten a spec III, since most everyone says a spec III is the one *they* got.
i concluded that what is going to hurt the clutch the most is the drag launches (clutch dumps) that people do to their clutches, not just my normal *** driving on the street. what do ya think? i'm hoping to put at least 25k miles on this clutch (i plan to sell the car by the time i get to 25k miles from now). i'm just trying to decide if i got the right clutch for my application. i thought i did until after i installed it, and then i wondered...
i concluded that what is going to hurt the clutch the most is the drag launches (clutch dumps) that people do to their clutches, not just my normal *** driving on the street. what do ya think? i'm hoping to put at least 25k miles on this clutch (i plan to sell the car by the time i get to 25k miles from now). i'm just trying to decide if i got the right clutch for my application. i thought i did until after i installed it, and then i wondered...
05-12-2005, 10:20 AM
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Drag launches should be the last of your worries. A clutch dump at 6K doesn't hurt a clutch unless you dead hook. If you try to race someone and you don't dump the clutch you just did a ton more damage then dumping the clutch. Good topic though. Here is a list of things I think you really need to worry about.
Updated Hydrolics - newer slave, drill mod, adjustable master.
Hydrolics bled properly
Slipping the clutch - street or strip, don't rev to 5k and slowly let the clutch out.
Don't heat the clutch up in the water box. I put the car in 2nd gear, engage Line loc, raise rpms to 4K and drop clutch, raise rpms to 6k, once I see smoke I release the line lock and push in the clutch. You will have enough wheel spin that it will pull you out of the water box. Don't have the clutch engaged while spinning out of the water box. If you do what happens is the tires hook, and the clutch stops the rpms of the motor, which is not good for the clutch plus it adds a lot of heat. You don't want that heat in the clutch when your about to launch.
Dan
99 T/A 555 rwhp M6 10.6 @129 1.42 60ft.
Updated Hydrolics - newer slave, drill mod, adjustable master.
Hydrolics bled properly
Slipping the clutch - street or strip, don't rev to 5k and slowly let the clutch out.
Don't heat the clutch up in the water box. I put the car in 2nd gear, engage Line loc, raise rpms to 4K and drop clutch, raise rpms to 6k, once I see smoke I release the line lock and push in the clutch. You will have enough wheel spin that it will pull you out of the water box. Don't have the clutch engaged while spinning out of the water box. If you do what happens is the tires hook, and the clutch stops the rpms of the motor, which is not good for the clutch plus it adds a lot of heat. You don't want that heat in the clutch when your about to launch.
Dan
99 T/A 555 rwhp M6 10.6 @129 1.42 60ft.
05-12-2005, 01:29 PM
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Originally Posted by TAGOES11S
Don't heat the clutch up in the water box. I put the car in 2nd gear, engage Line loc, raise rpms to 4K and drop clutch, raise rpms to 6k, once I see smoke I release the line lock and push in the clutch. You will have enough wheel spin that it will pull you out of the water box. Don't have the clutch engaged while spinning out of the water box. If you do what happens is the tires hook, and the clutch stops the rpms of the motor, which is not good for the clutch plus it adds a lot of heat. You don't want that heat in the clutch when your about to launch.
Dan
99 T/A 555 rwhp M6 10.6 @129 1.42 60ft.
Dan
99 T/A 555 rwhp M6 10.6 @129 1.42 60ft.
05-12-2005, 09:19 PM
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>> Updated Hydrolics - newer slave, drill mod, adjustable master. Hydrolics bled properly
How does this effect the holding force of a clutch? Is this not for consistant engagement.
How does this effect the holding force of a clutch? Is this not for consistant engagement.
05-13-2005, 08:03 AM
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The hydrolics play a major factor in the engagement point. If there is air in the line it will move the engagement around. A lot of people have this problem. In fact I just had a seal go out 
in my Mcleod Master cylinder which caused air to get in. By the time I caught it I had to rebuild my Mcleod twin disk. It had about 5,000 miles on it. Seemed normal on the street but it wouldn't hold when I went to the track because it wasn't disengaging completely. Which caused it to wear out that quick. When the hydrolics are working I can drive it on the street daily and make 15-20 passes on the track a week all summer long with no problems. I run et Drags and launch at 5K on the bottle, which lifts the front about 2 feet. So the holding power of the clutch is fine 
It's making sure the hydrolics don't play with the engagement point.
Do a search and you'll see the problems people have with the stock MC, lines, and older slaves.
in my Mcleod Master cylinder which caused air to get in. By the time I caught it I had to rebuild my Mcleod twin disk. It had about 5,000 miles on it. Seemed normal on the street but it wouldn't hold when I went to the track because it wasn't disengaging completely. Which caused it to wear out that quick. When the hydrolics are working I can drive it on the street daily and make 15-20 passes on the track a week all summer long with no problems. I run et Drags and launch at 5K on the bottle, which lifts the front about 2 feet. So the holding power of the clutch is fine It's making sure the hydrolics don't play with the engagement point. Do a search and you'll see the problems people have with the stock MC, lines, and older slaves.
05-14-2005, 01:20 AM
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Originally Posted by TAGOES11S
The hydrolics play a major factor in the engagement point. If there is air in the line it will move the engagement around. A lot of people have this problem. In fact I just had a seal go out in my Mcleod Master cylinder which caused air to get in. By the time I caught it I had to rebuild my Mcleod twin disk. It had about 5,000 miles on it. Seemed normal on the street but it wouldn't hold when I went to the track because it wasn't disengaging completely. Which caused it to wear out that quick. When the hydrolics are working I can drive it on the street daily and make 15-20 passes on the track a week all summer long with no problems. I run et Drags and launch at 5K on the bottle, which lifts the front about 2 feet. So the holding power of the clutch is fine It's making sure the hydrolics don't play with the engagement point.
Do a search and you'll see the problems people have with the stock MC, lines, and older slaves.
in my Mcleod Master cylinder which caused air to get in. By the time I caught it I had to rebuild my Mcleod twin disk. It had about 5,000 miles on it. Seemed normal on the street but it wouldn't hold when I went to the track because it wasn't disengaging completely. Which caused it to wear out that quick. When the hydrolics are working I can drive it on the street daily and make 15-20 passes on the track a week all summer long with no problems. I run et Drags and launch at 5K on the bottle, which lifts the front about 2 feet. So the holding power of the clutch is fine It's making sure the hydrolics don't play with the engagement point. Do a search and you'll see the problems people have with the stock MC, lines, and older slaves.
It's really a combination of characteristics that will destroy the life of a clutch. However, I still firmly believe slippage is the number 1 reason. A clutch in and of itself is a friction material, such as sandpaper, a file, or brake pads. Now all of these materials will wear away after some time, some slower than others.
The point is, the better friction material, the less street friendly properties it will have.
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05-20-2005, 06:59 AM
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This is a great post, everyone should read it!!! Heat is the number one enemy, the more aggressive the friction material (higher coefficient of friction) the more able to handle the heat and abuse.
Also the burnout thing is dead on - when the tires hook rolling out of the water it puts extreme stress on the clutch. We aren't Pro Mods and shouldn't drive like it!
Last factor not mentioned - dynos. A car on the dyno is going to dead hook and when the load is applied, it will stress the clutch harder than a drag race launch!
Mike
Also the burnout thing is dead on - when the tires hook rolling out of the water it puts extreme stress on the clutch. We aren't Pro Mods and shouldn't drive like it!
Last factor not mentioned - dynos. A car on the dyno is going to dead hook and when the load is applied, it will stress the clutch harder than a drag race launch!
Mike
05-20-2005, 07:59 AM
#9
Wow, the burnout thing is a great piece of advice I'd never been told. I had been spinning through the burnout after releasing the lock and releasing the clutch once I felt it hook. Once when I did this about a year ago, the trans locked up on the starting line on me, wouldn't go into any gear and I had to be pushed off. Let it cool down and everything was ok, but I never figured out why it happened. I'll heed your advice from now on.
