Functional components of clutch systems expanding on ws6transam's post
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From: Youngstown, Ohio, USA
Functional components of clutch systems expanding on ws6transam's post
ws6transam did an excellent job explaining torque converter torque multiplication. However, he did leave a the clutch field somewhat unexplained. I will explain those here. This is not about clutch torque multiplication, because it simply doesn't happen. This is about clutch slippage, torque, and clutch disc/flywheel sizes.
Now, as mentioned before clutch slippage is a function primarly of friction, surface area, pressure plate pressure and resistance. However, one more force remains. Leverage or mechanical advantage. Take your hand and a plate on the table. Put all your fingers tightly together in the center of the plate and attempt to turn it. The friction applied by the force of your fingers overcomes the friction of the plate against the table. However, now spread your fingers as far as they can go and turn the plate. Easy, right? This is because you now have an advantage, leverage, over the friction of the plate. In effect, this applies to clutches also. The larger the clutch, and the larger the flywheel, the less it slips provided all other factors are equal. By increase clutch disc size and flywheel size you reduce the need for extreme amounts of pressure to be applied by the pressure plate.
This all means as you increase resistance, usually by adding traction, but also weight, or adding torque, causing the engine to have the power to overcome the frictional force of the clutch and slip, you decrease the time of 1:1 transfer. (Note: This doesn't apply to street tires because especially on these cars they're a rather easy resistance to overcome). The bigger flywheel you get, you gain mechanical advantage and also more mating area for the clutch as a 1" band 1" from the center of a circle is less area than a 1" band 2" from the center.
The idea in racing is to reach 1:1 transfer with a clutch as quickly as possible. Remember energy can neither be created or destroyed, if you're running a small flywheel/clutch on slicks with a weak PP what doesn't go to the rear wheels becomes heat.
------------------
1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 WS6 Trans Am T-top car
4-bolt main 350, headers, Holley 650, T-5 and 3.23's.
Daily driver and restoration
Now, as mentioned before clutch slippage is a function primarly of friction, surface area, pressure plate pressure and resistance. However, one more force remains. Leverage or mechanical advantage. Take your hand and a plate on the table. Put all your fingers tightly together in the center of the plate and attempt to turn it. The friction applied by the force of your fingers overcomes the friction of the plate against the table. However, now spread your fingers as far as they can go and turn the plate. Easy, right? This is because you now have an advantage, leverage, over the friction of the plate. In effect, this applies to clutches also. The larger the clutch, and the larger the flywheel, the less it slips provided all other factors are equal. By increase clutch disc size and flywheel size you reduce the need for extreme amounts of pressure to be applied by the pressure plate.
This all means as you increase resistance, usually by adding traction, but also weight, or adding torque, causing the engine to have the power to overcome the frictional force of the clutch and slip, you decrease the time of 1:1 transfer. (Note: This doesn't apply to street tires because especially on these cars they're a rather easy resistance to overcome). The bigger flywheel you get, you gain mechanical advantage and also more mating area for the clutch as a 1" band 1" from the center of a circle is less area than a 1" band 2" from the center.
The idea in racing is to reach 1:1 transfer with a clutch as quickly as possible. Remember energy can neither be created or destroyed, if you're running a small flywheel/clutch on slicks with a weak PP what doesn't go to the rear wheels becomes heat.
------------------
1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 WS6 Trans Am T-top car
4-bolt main 350, headers, Holley 650, T-5 and 3.23's.
Daily driver and restoration
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