Why do you have to double clutch when street racing?

Answer 1

You don't. Unfortunately, "The Fast and the Furious" would like us all to believe that Mr Diesel is the pro-est of the pro, but sadly, it just shows how out of touch the screenwriters are. If you double clutch when you shift, it can spare the transmission from un-due harm since it lowers your chance of missing the gear by syncing the flywheel a little more closely to the transmission input shaft speed. Almost no street racer does this simply because stock syncros do a pretty good job already in modern cars. Professionals use almost exclusively automatic transmissions since manuals are really easy to break on accident at over 900 hp.