I did it....just for fun. If you get off the clutch fast...it will grab. the tires just spin and spin...and you don't move much. A little side to side motion...if you keep the throttle pressed all the way. It isn't that much harder on the car then a 7k launch.

 

Just a little physics for the 9k clutch drop. Kinetic Energy (in this case rotational energy) is proportional to the velocity squared (in this case, the rotation rate squared). Thus, at 9k, the instantaneous energy the spinning side of the clutch, combined with the engine, is 4x greater than at 4.5k (assuming drive wheels and tranny aren't moving). Spoken another way, a clutch slipping at 9k on a motionless car, dumps 4x the energy (read: clutch smell and wear) than at 4.5k into the clutch subsystem. This is why you can slip your clutch to start at 2-3k w/o noticable smell or wear, but a 6-9k slip gets so smelly and damaging. (9k has nine *times* the friction energy going into the clutch surface to heat it up vs 3k).

A 9k clutch drop vs 6k, assuming the same time to "grip" (which it won't be, the clutch pressure is the same, but there's a greater rotation rate differential) will impart 2.25 times the heat/friction energy into the clutch (1.5x speed differential, squared = 2.25). Even with the tires breaking loose, you're still talking considerably more wear and tear onto the clutch, by my guess at least 2x.

 

Dang hoof... That hurt my head reading that.

I wouldn't do it. But please let us know how it goes.

 

i've done it before...just for fun too
it was really late at night and a good friend had come down to visit

i did it at 8500rpm (i think that's close enough to 9000rpm)...i know i dropped the clutch as fast as i could, but i still smelled a slight burn coming from my clutch, but my friend smelled nothing...it kept spinning, without any grip, and had to hold on tight, i couldn't help but to slide slightly into the lane next to me (my right). it wasn't fun or scary, i just know that i won't do it again
i recommend no more than 6000rpm, 'cause you could lose control if you aren't paying enough attention

 

If your clutch doesn't slip, you have the same wear at 9K as you do at 4K, just more driveline shock and tire wear. 9K drops are nice, for show, and the stock clutch will take many of them...trust me, but the best launch is more near 7,500K (depending on the surface).

Andrew

 

Be careful, you might smell cat pee!

 

Actually S2Kguy, assuming the same case (slip vs no slip), 9k will do approximately 5x the wear of 4k, even with the same slip time to accelerate the wheels. This is simply because you have to get the drivetrain and the engine to the same speed. Same speed = no slip. Not same speed = slip. Granted the time it takes to match speeds is rather quick, esp. if the wheels break loose right the way, however 9k is over 2 times faster than 4k, so the wheels will take approximately 2x the time to accelerate. So not only do you have significantly more time in slippage, but the slippage speed differential averages more than 2x as high (read 4x the energy).

If you wish to believe that wear is the same at 9k vs 4k when the clutch grabs, go right ahead Your car was designed on the principals of Physics, and the clutch obeys those laws just like the rest of your car

 

[QUOTE]Originally posted by hoof
[B]Actually S2Kguy, assuming the same case (slip vs no slip), 9k will do approximately 5x the wear of 4k, even with the same slip time to accelerate the wheels.

 

[QUOTE]Originally posted by hoof
[B]Actually S2Kguy, assuming the same case (slip vs no slip), 9k will do approximately 5x the wear of 4k, even with the same slip time to accelerate the wheels.

 

[QUOTE]Originally posted by hoof
[B]Actually S2Kguy, assuming the same case (slip vs no slip), 9k will do approximately 5x the wear of 4k, even with the same slip time to accelerate the wheels.