Clutch in.
Shifter to neutral.
Clutch out.
Rev to appropriate RPM for syncros.
Clutch in.
Shifter into desired lower gear while rev matching.
Clutch out.

Why do it?
---save syncros, You should really ONLY do this if your syncros are screwed up. The fact that your pulling teh clutch in and out will only wear out the clutch faster, their really isn't any point other than that.
Does it make you faster? No. Why not? Think about it, your spending more time without the engine engaged. For our cars, all that is neccesary when downshifting is to rev match (or blip throttle before engaging the clutch)

 

have a

 

 

sorry had a good mpeg which explains but can't load it up...

Indeed the technique is just rev matching assisted by heal and toe.

 

I loved when Vin Diesel used this phrase in the first abomination of a car movie. Double clutching is rather useless. I saw a nice young dumbass at the track trying to experiment with the technique as he "was told by his dad that the extra revs and dumping the clutch would accelerate the car faster". I tried to explain that the more time a motor spends disengaged from the driveline, the more time wasted. He gave me a "whatever".

 

There is some truth to that. It's called slipping the clutch and it will get you more low-end torque. It will also burn your clutch to smitherines, but that's aside from the point. No, it's not double-clutching really, but I guess it's similar.
-N

 

Thats not what he was doing, he was actually double clutching. I usually keep my throttle foot pinned to the floor when I shift, allowing clutch slip. This guy was leaving the line, revving it out, going into neutral and revving the hell out of the motor for at least a second, then dumping the clutch. Unecessary.

 

Well, yes unnecessary to do that, but perhaps they thought doing it with the double clutching would somehow protect the clutch from melting. I'm not saying he wasn't being a little dumb and probably should have just learned a little about clutches rather than what he was doing, but it wasn't completely off-base. And realistically, his "whatever" was probably based on the fact that he could feel getting more torque from slipping it, doing just what his father said while you were telling him it was wrong.
-N

 

Understood Neil, but just like popping the clutch on a motorcycle, it feels like a slingshot effect (as to what he was trying to explain sounded much like that). He wasn't attempting anything, he just thought revving the motor hard and dropping the clutch would work better. It doesn't.

 

Have any of you seen GIS2 (Get Away in Stockholm 2), The driver of the Escort Cosworth slips the clutch on some of the slower corners to keep the revs and to stop the car from bogging down. You can hear this as the revs suddenly rise and fall a few times whilst accelerating. Now his car is heavily modified and he prolly has a 3 puck clutch, so to stop the car from stalling and bogging down he slips the cutch a little to keep the revs going and then the car launches up the road. I dont think this is necessary in an EVO let alone an ordinary lancer in most road conditions. Maybey on some hill climbs or closed road events where you pushing at the maximum.

regards
Mimmo

 

It's the same deal as everywhere else. It's necessary in any case when you want more torque, don't want to downshift, and don't care about melting yoru clutch. The driver of the Escort Cosworth clearly fit all three characteristics.
-N

 

No, double clutching was meant to save gears before synchromesh trannies existed. Synchros made this unnecessary. The synchros are there for the very purpose to not have to double clutch to shift without gears grinding.

 

Yo I GOT A ? Whe you dobble cluch dosent that mess up the transmission? Is that tru? And when u dobble cluh how much rpm do do you do it on?

 

Did you read this thread? It should be clear that double-clutching can't hurt anything. And also that double-clutching has nothing to do with engine speed. Rev-matching which is commonly combined with double-clutching (though it needn't be) is about matching engine speed with drivetrain speed so that the clutch engages with little effort and is the least amount of stress (and friction) you can put on your clutch if you're good enough.
-N