Did i burn the clutch ?

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tiptopd
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Did i burn the clutch ?

Post by tiptopd » Fri Dec 11, 2015 1:35 pm

Had a brain fart moment today and decided to test the clutch :roll:
Pulled up the handbrake, shifted into 3rd. Revved up to 1200RPM and held it there.
Started releasing the clutch and saw the REVS drop to 1000RPM around halfway or slightly higher of the clutch travel. Held it there for some seconds, maybe a max of 10 seconds while i was deciding whether or not to let it all out in order to try and stall the car.
It was obvious it was gonna stall so decided to clutch in and shift neutral.
Didn't notice any clutch smell even though i just turned it off and got out shortly after.
Did i take too much life out of that poor clutch ?

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Re: Did i burn the clutch ?

Post by tankinbeans » Fri Dec 11, 2015 2:06 pm

Out of curiosity, why? Is there a problem you're trying too diagnose?

That sounds abusive, but if it's not a regular thing probably not a huge deal.
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Re: Did i burn the clutch ?

Post by theholycow » Fri Dec 11, 2015 4:54 pm

I wouldn't worry about it unless you notice any problems. 10 seconds at 1000 rpm medium throttle sounds like 10 launches worth of wear to me...probably not enough all at once to overheat it and cause any kind of damage.
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tiptopd
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Re: Did i burn the clutch ?

Post by tiptopd » Fri Dec 11, 2015 5:45 pm

theholycow wrote:I wouldn't worry about it unless you notice any problems. 10 seconds at 1000 rpm medium throttle sounds like 10 launches worth of wear to me...probably not enough all at once to overheat it and cause any kind of damage.
i set the throttle at 1200rpm with the clutch fully in and didn't move it anymore, so there was very little throttle. I am worried just because i was in 3rd gear.

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Re: Did i burn the clutch ?

Post by IMBoring25 » Fri Dec 11, 2015 6:14 pm

If the car never moved gear doesn't matter.

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Re: Did i burn the clutch ?

Post by tiptopd » Fri Dec 11, 2015 6:40 pm

IMBoring25 wrote:If the car never moved gear doesn't matter.
but i thought you have to put more load on the clutch side by putting it into 2nd, 3rd or 4th so you can test for slippage :|
if it doesn't matter than why do most folks test it on those gears with the handbrake on ?

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Re: Did i burn the clutch ?

Post by IMBoring25 » Fri Dec 11, 2015 8:01 pm

In higher gears the engine has poorer leverage. You're likelier to stall the car whereas you might actually have the car move in first.

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Re: Did i burn the clutch ?

Post by six » Fri Dec 11, 2015 9:33 pm

If you wanted to test for slippage, you should have just released the clutch all the way all at once. The car should stall immediately. Any other behavior will point to a slipping clutch.
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Re: Did i burn the clutch ?

Post by Rope-Pusher » Fri Dec 11, 2015 11:25 pm

Testing for slippage is all too easy. Drive in 1st gear, at rpm corresponding to where the engine achieves peak torque. Mash the accelerator and the brake pedal at the same time. If the vehicle comes to a stop and the engine stalls, clutch is good. If the vehicle comes to a halt, but the engine is still running, then the clutch is slipping.
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tiptopd
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Re: Did i burn the clutch ?

Post by tiptopd » Sat Dec 12, 2015 6:02 am

IMBoring25 wrote:In higher gears the engine has poorer leverage. You're likelier to stall the car whereas you might actually have the car move in first.
cool, so basically the same amount of wear as if i did a few hill starts with the handbrake method, right ?

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Re: Did i burn the clutch ?

Post by tiptopd » Sat Dec 12, 2015 6:07 am

Rope-Pusher wrote:Testing for slippage is all too easy. Drive in 1st gear, at rpm corresponding to where the engine achieves peak torque. Mash the accelerator and the brake pedal at the same time. If the vehicle comes to a stop and the engine stalls, clutch is good. If the vehicle comes to a halt, but the engine is still running, then the clutch is slipping.
isn't that how you burn a clutch while attempting a burnout :lol: too much brake so the wheels can't spin and too much throttle so it doesn't stall, something has to slip, the poor clutch
anyway, RP do you think i did much damage ? I need you opinion in this :)

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Re: Did i burn the clutch ?

Post by vw100 » Sat Dec 12, 2015 4:22 pm

There are a lot of people holding their cars uphill only with the clutch like 5s before the light turns green, so i guess nothing to worry about here.

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Re: Did i burn the clutch ?

Post by Rope-Pusher » Sat Dec 12, 2015 6:07 pm

tiptopd wrote:
Rope-Pusher wrote:Testing for slippage is all too easy. Drive in 1st gear, at rpm corresponding to where the engine achieves peak torque. Mash the accelerator and the brake pedal at the same time. If the vehicle comes to a stop and the engine stalls, clutch is good. If the vehicle comes to a halt, but the engine is still running, then the clutch is slipping.
isn't that how you burn a clutch while attempting a burnout :lol: too much brake so the wheels can't spin and too much throttle so it doesn't stall, something has to slip, the poor clutch
anyway, RP do you think i did much damage ? I need you opinion in this :)
The clutch design is chosen so that it will always transfer more than full rated engine torque without slippage, so the engine should always stall when you do this procedure. You really aren't overheating the clutch this way, since you started the test with the clutch fully engaged and it never slips during the test if it is successful.

If you held the throttle down to where the engine was running at 1,200 rpm with no load, the engine wasn't making all that much torque, just enough to overcome drag and pumping losses. If you kept the throttle at that position, but let the clutch engage enough to drag the rpm down to 1,000 rpm, you weren't transmitting much torque through the slipping clutch. If you really only did this for about 10 seconds of time, then the clutch didn't get overheated. No significant damage was done.
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Re: Did i burn the clutch ?

Post by tiptopd » Sat Dec 12, 2015 7:06 pm

Rope-Pusher wrote:
tiptopd wrote:
Rope-Pusher wrote:Testing for slippage is all too easy. Drive in 1st gear, at rpm corresponding to where the engine achieves peak torque. Mash the accelerator and the brake pedal at the same time. If the vehicle comes to a stop and the engine stalls, clutch is good. If the vehicle comes to a halt, but the engine is still running, then the clutch is slipping.
isn't that how you burn a clutch while attempting a burnout :lol: too much brake so the wheels can't spin and too much throttle so it doesn't stall, something has to slip, the poor clutch
anyway, RP do you think i did much damage ? I need you opinion in this :)
The clutch design is chosen so that it will always transfer more than full rated engine torque without slippage, so the engine should always stall when you do this procedure. You really aren't overheating the clutch this way, since you started the test with the clutch fully engaged and it never slips during the test if it is successful.

If you held the throttle down to where the engine was running at 1,200 rpm with no load, the engine wasn't making all that much torque, just enough to overcome drag and pumping losses. If you kept the throttle at that position, but let the clutch engage enough to drag the rpm down to 1,000 rpm, you weren't transmitting much torque through the slipping clutch. If you really only did this for about 10 seconds of time, then the clutch didn't get overheated. No significant damage was done.
nice to hear that :D it was probably less than 10 seconds
now i am curious how do they burn those clutches on youtube while attempting to burnout. You can hear the engine revving near redline and tires don't move at all.Always thought it was too much brake and too much throttle, but you confused me a bit here :?

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Re: Did i burn the clutch ?

Post by Rope-Pusher » Sun Dec 13, 2015 3:09 pm

They didn't have enough clutch to do the job. You need the clutch's ability to transmit torque to be greater than the engine's ability to produce torque. If the clutch can't transmit all that the engine can procduce, it will slip. Slipping under a high torque load and lots of RPMs makes lots of heat, which will overheat the friction surfaces of the clutch disk. The flywheel will absorb some of this heat, but the pressure plate is generally less massive and will get hotter and not absorb as much heat. You can see this sometimes in tht the pressure-plate side of the friction disk tends to wear more or get glazed more than the flywheel side. If the pressure plate gets too hot, it can fracture from the stress of uneven expansion.
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