what's double clutching and how does it work

[DirtyBird17]

thinking about getting an m5 and was wondering how to douible clutch. what does it do and how does this work.

[Deuce Bigs]

it's where the tranny doesn't have synchros built in so you have to push in the clutch to let the gear out then you have to push it in again to put it in gear. basically if you're getting it from fast and furious don't pay attention to it. you don't need to worry about it. they said it cause it sounds cool. the new wrx's have trannies you can buy they affectionately call dogboxes cause there are no synchros adn they are hella strong but that's the only thing i know of besides big rigs. [img]smile.gif[/img]

[Wicked 3800 V6]

It's not using two clutches. [img]smile.gif[/img]

When downshifting (i.e. 4th on a 45mph doing 55mph road to 35ish on a 30mph road in 3rd gear), it's matching revs so that everything engages smoothly and there is no wear on the transmission syncrhonizers, which would normally do the synching themselves.
Clutch out -- pedal pushed down
clutch in -- foot off pedal
From 4th to third:
clutch out
4th to neutral
clutch in
blip (add like 1k revs, i always seem to drop 800 to 1700 when shifting up to the next gear at 2500, so add about 1k to make the 1700 (40mph) in 4th to 2500 in third (40mph)
clutch out
neutral to third
clutch in

Don't forget what's around you, and to steer and brake and such. easy to do when occupied with a new task.

and go!

Truthfully, it works great, and it will become second nature if you do it and do it and just practice trying to do it whenever you downshift. I even do it when borrowing a car that's not mine ... very good on the transmission, and you'll need to know it if you ever get in a full-dog transmission race-car, which has dogs instead of synchros. Woof ... (no not those dogs).

[edit]BTW, some people VERY INAPPROPRIATELY mention this as merely blipping the engine when going between gears. What they're missing is the true synch process, where you synch the lagshaft to the engine speed by letting the clutch up in neutral. just trust me on this. think of the clutch connecting the engine and tranny, and the gearshift connecting the wheels and tranny. gotta match them all to speed to be smooth. And it's the most described / important topic in Skip Barber's "Go Faster! mastering the art of race car driving" Screw up a downshift when at low traction and you'll spin.[/edit]
-Rob

[ January 29, 2002: Message edited by: Wicked 3800 V6 ]</p>

[DirtyBird17]

thanks guys, yeah i did first hear it on the fast and the furious, but this dude that rides with me to golf practice says that he has a 280zx that he does it in. he says it's like a boost effect whenever he does it but i don't think he knows what he's talkin' about. also just saw this same post in the lounge, sorry about the double post.