Ive seen some people shifting really fast by stomping on clutch without lifting their foot from the gas pedal. Does this weaken the transmission or clutch any and whats the best way to do it so you're not killing your car too much?

 

Unless you have a standalone ECU which allows this feature (it's useful with a turbo because you don't close the throttle plate so the turbo doesn't spool down) or some engine that revs up so slowly that it won't bounce off the rev limiter while you're shifting I say it's not a good idea.

Basically you can look at it like dropping the clutch from redline in any other situation. A lot of extra shock, wear, and potential to break things.

 

Sounds like a good way to shatter the friction plate. If you want quicker shifts, buy a short shifter/ new bushings and play with the throw on your clutch pedal.

 

I have a friend that swore by that. I lifted during my shifts and he didn't. His trans blew up and mine didn't. Hmmmm... So no gains at the track from what I could see for the N/a car and makes the trans uphappy

Here is the thing with that (not counting what Floyd was talking about with boost). You want your revs right where the next gear is going to put your engine with the clutch engaged. Your clutch is going to have to act as a brake for the engine to get it down to where the revs are at for the next higher gear if you stay on it. I fail to see how that would help. Just like a downshift, match revs and you will be better off. If you lift off as you shift your still normally a little higher than you need to be unless you shift reallllyyy slooowww... so IMO

don't do it

Unless you have boost then not slowing the turbo especially if you have a bad-ass clutch may be a good thing.. heh.

 

the only time this is any good is if you have a two step installed. this allows you to set the rpms when your shifting to where you want them so you can keeo your foot on the gas. this is good for turbo cars so they dont have to spool back up, or for vtec cars so when there wot they never leave vtec while shifting.

 

It's call full throttle ignition-cut, and its available as an upgrade on some of the more expensive ECU's. This is the only way you will shift at full throttle, without damaging transmission parts. If you are going to shift without the clutch, you need to lift. And you need to lift to unload the synchro rings, which means lifting and pushing through at the correct time, in the correct time period.

The time gained is minimal at best, and weighed against the risk it is best not to do this.

 

I've been doing this for some time with the 3 step built into my Megasquirt that's hooked to the clutch pedal. The misconception is thinking your revs will actually drop once activated. The truth is they hover at about the point where it was engaged. I'm guessing the the motor has so much inertia it fails to slow down very quickly. I have my launch set at 2800 rpm, flat shift set to 3800, and shift at about 6500. When I flat shift the revs sit at about 6500 until the clutch has engaged then drops to about 5200.

 

I release the gas and press the clutch, then right before I release the clutch, I press the gas. This makes the RPMs drop slightly and then gives me a boost after the synchronizers align. It would appear that I kept my foot on the gas to most though.

 

It's a very very quick action and you have to time it so you release the gas RIGHT before the clutch disengages so the rpms drop.

 

I've destroyed a lot of transmissions.. enough to tell you slamming gears is bad on a stock trans. Focus on you clutch throttle control it will really help you for accelerating and braking. Leveling your RPMS to the gear you are going for paired with the beautiful NO ABS setup in our tiburons and some practiced heel to toe work on the gas and brake and you can slam any friends head into the dash without making a peep out of your tires.