r/performancedriving • u/TachankaTHICC69 • Jan 23 '19

It's about clutches

I got a question why when the people that are racing push and release the clutch so quick won't it stall or kill the clutch? I'm not really knowledgeable about this stuff, i just wanted to know more about these kind of stuff.

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u/Scooby207 Jan 23 '19

The clutch is what connects the engine to the transmission. There are a ton of good YouTube videos if you want to see how this works. When you see people racing and they are shifting quickly, it's to go between gears very quickly, or to get the car to shift weight. Shifting weight takes weight off of two of the tires, which makes it easier to turn or drift. The clutches used are more durable, so those hard quick shifts aren't really that bad on it. All clutches wear, and race car owners accept they will replace their parts much sooner than their street cars.

3

u/obsa Jan 23 '19

Good points. To address something in OP's phrasing, pushing the clutch (disengaging it) will never cause a car to stall unless there's some other major issue. Quick releases of the clutch can stall the car, but when the vehicle is moving the momentum of the entire chassis is typically what prevents a stall -- unless the vehicle is moving too slowly.

In scenarios like /u/Scooby207 describes, the vehicle typical has more than enough momentum to prevent a stall.

1

u/tujuggernaut Jan 24 '19

Cars only stall when the torque of moving the car is too great for the engine. E.g. first gear starts. The rest of the time, as others said, the engine is connected to the wheels through the transmission, so it is mechanically coupled and unlikely to stall once moving.

Tidbits:

  • You can shift without the clutch entirely. This is how you have to drive a dog box but it works on a synchromesh transmission also. Better know how to rev match though.

  • In F1, the shift time is now measured in milliseconds as opposed to tenths of seconds. Their shifts are accomplished via pneumatic or hydraulic actuators controlled by paddles on the wheel, but still only have 1 clutch (no DCT).