double clutching...fast and the furious anyone??? anyway, why not blip the throttle instead? rev-matching is actually the name of the game, and the car gets less un-settled when using it (technique) for going fast in a turn.
the geek

 

DOUBLE CLUTCHING:
There are *three* separate spinning entities that need to be coordinated when shifting: The engine. The transmission input. (I'm going to refer to this as the intermediate shaft). The transmission output (which is directly related to the vehicle speed).

When the clutch is disengaged (pedal pushed down) and the transmission is in neutral (such as when shifting between two gears), the intermediate shaft is essentially free spinning. In normal shifting, we rely on the synchro's to control the speed of the intermediate shaft as it engages with the gears connecting it to the transmission output.

Decades ago, transmissions didn't have synchro-mesh. (Many large trucks still don't). On these transmissions, it is necessary for the driver to manually control the speed of the intermediate shaft so that it matches the speed of the gear to be engaged. This is done by the following process when shifting from one gear to the next:

1) Power is removed and clutch is disengaged (pedal down). 2) Transmission is shifted from original gear to neutral. 3) Clutch is re-engaged (pedal up). (Driver now has control of intermediate shaft speed by controlling engine speed). 4) Driver 'blips' throttle to match intermediate shaft speed to speed of new gear. (This takes practice to get the right match). 5) Clutch is disengaged (pedal down). 6) Transmission is shifted from neutral into new gear. 7) Clutch is re-engaged (pedal up) and power is applied.

Steps 1 - 3 can be done casually or quickly. Steps 4 - 6 *must* be done quickly so that the intermediate shaft doesn't slow down again before it's engaged. If step seven is also done quickly, the engine will also be 'rev-matched' to the rest of the driveline so that engagement will be smoother.

REV-MATCHING:
When taking off from a stop and then going up through the gears, steps 1,2,6,7 above are the normal shifting method for each gear change. The synchro-mesh are more than enough to control the intermediate shaft speed. The engine will passively rev-match itself because it slows down naturally and this is appropriate when shifting up.

When down shifting, the engine needs to spin faster as it engages the new gear. This can be achieved by 'blipping' the throttle as the transmission passes through neutral. If the engine isn't manually sped up by the driver, it will be sped up by the driveline when the clutch is re-engaged. This can be OK for normal street driving, but if the car is cornering near the limit this can upset the suspension and the tire adhesion.

The synchromesh are usually adequate intermediate shaft control when down shifting one or two gears. Aggressive downshifts (like a 5 - 2 shift from high speed) can benefit by using double-clutch shifting to assist the synchro's. Shifting into first gear in a hard corner is nearly impossible without double-clutching (this is useful for those really tight hairpins, especially if they exit uphill).

http://www.happytogether.com/318ti/n...ing/index.html

 

blah. just grind em till they fit.
If your drag racing, or even just driving on the street....don't even worry your self with double clutching or rev matching or left foot brakeing or any of that shit...

 

odviously dude wasn't driving a domestic

 

thanks for all the info cause i think my syncros are gone in 2nd and third

 

Look, here's the potatoe-head explanation...
Double-Clutching = Only used on non-synchronized transmissions, no real world application besides race trannys, semi's and ~70's and under trannys.
Heel-Toe = used to slow the car and change gears at the same time to keep a smooth transition through a turn.

 

This is dumb funny.....Go watch TFATF...Damn you should know you have to double clutch,,,,just ask Vin D.

 

if you really want to shift fast... just bang it in to gear, dont use the clutch, and dont let off the gas.... thats power shifting!!!! its how i shift, and i can drive the shit out of anything you put me in. although your tranny may not hold up like it should.... hahahahah

 

ok....im not doing that..thats just plain stupid and i have a vw..my tranny is a piece anyways..i know someone that replaces tranny's more often than he changes his oil

 

ok you are wasting time letting the clutch back out while in neutral you only need to do that if you have bad syncros the best thing to do is push clutch in blip the gas up to where the rpms should be for the speed and gear while at the same time putting it in that gear soon as there matched let clutch out and let her rip or you can if you have some ponies on tap unlike that vtech and rev it way higher then it needs to be and let the clutch fly and induce some tire spin to make said vtech look like a real punk