Race Clutch
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From: Santa Cruz, CA, US
because I drove 1 time with you and tom that means I don't think it's stupid? We went in the middle of the night too. We never made it to 4 corners either.
That was the first and last time in ~4-5 years and was well over a year ago.
That was the first and last time in ~4-5 years and was well over a year ago.
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From: Toronto, Canada
Originally Posted by INTJ,Oct 3 2007, 11:35 AM
Now I'm confused!
1. The flywheel is rotational mass on the end of the crank, just like a piston, (worse it is mass at a larger radius). The engine will accelerate faster with a lighter flywheel.
This is really the old torque/hp argument. People with strip machines want/don't care about engine mass as much because because it helps with torque. Wind up a 10,000 rpm rubber band airplane with a .1 gram propeller, compare to a 2 rpm 60 foot diameter 1000 kg water wheel, which one would you stick your hand in front of....
2. The heavy mass allows slow drivers to catch up on the clutch slipping (decays slower), light mass allows faster shifting because it hits the rev match point faster.
1. The flywheel is rotational mass on the end of the crank, just like a piston, (worse it is mass at a larger radius). The engine will accelerate faster with a lighter flywheel.
This is really the old torque/hp argument. People with strip machines want/don't care about engine mass as much because because it helps with torque. Wind up a 10,000 rpm rubber band airplane with a .1 gram propeller, compare to a 2 rpm 60 foot diameter 1000 kg water wheel, which one would you stick your hand in front of....
2. The heavy mass allows slow drivers to catch up on the clutch slipping (decays slower), light mass allows faster shifting because it hits the rev match point faster.
That is an advantage in shifting because your blips are shorter and because the synchros have less rotational mass to slow down resulting in less synchro wear and faster shifts.
2. The heavy mass allows the driver to ease out the clutch from a dead stop without stalling by converting the rotational mass of the flywheel into heat. The less mass you have the less inertia there is in the flywheel which causes the clutch to grab and stall the engine much easier making it a bitch to drive on the street. In a race application you generally need to rev the snot out of the engine as you release the clutch (ether very slowly or very quickly but nowhere in between) replacing the mass with energy. Race cars typically have very small, very sticky and very lightweight clutches. Driving such a clutch in rush hour traffic would be enough to make you want to blow your brains out.
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Joined: Jul 2001
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From: Anaheim, Orange County
Actually the carbon twin plates are really streetable, and are the best race clutches on the market IMO. It's preferable over a puck style disk whether sprung or unsprung. Unfortunately the twin plates are not within the budget for most club racer cars or aggressive/high hp street cars. As Dave said, a lightweight flywheel, stiffer pressure plate and oem disk is reliable for most cars and has held north of 500 crank hp on my previous CTSCer.
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From: St. Louis
Originally Posted by cthree,Oct 3 2007, 01:19 PM
1. You are right, the engine will accelerate faster with a lighter clutch but only when the clutch is engaged. When the engine is connected to the transmission and drivetrain the weight of the flywheel is meaningless, the engine can only accelerate at the same relative rate as the drive wheels. The car doesn't accelerate faster, only the engine when spinning free of drive.
Of course, once you disconnect the rest of the drivetrain (as in clutch in revving), the flywheel becomes a much larger percentage of the mass being accelerated, and therefore cutting its weight has a much larger affect.
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From: Toronto, Canada
Originally Posted by FormulaRedline,Oct 3 2007, 04:30 PM
it still technically matters.
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From: St. Louis
Originally Posted by cthree,Oct 3 2007, 03:42 PM
Prove it. I say the mass of the flywheel, even the stock flywheel, represents a tiny fraction of the total rotational mass of the entire drivetrain, wheels and tires with the clutch disengaged, a fraction so small that it's technically irrelevant to the point of being almost immeasurable on typical commercial dyno.
I just wanted to make sure that distinction was clear, as that's not what I was getting from many of the posts.