[kwakr738]

What is a double clutch, what is it used for, and how do you do it?

[uhn2000]

http://en.wikipedia.org/wiki/Double_clutch

Basically your blipping the engine before re-engaging the next gear. Clutch, rev, clutch, change. You can do it one motion like clutch rev engage. That is what I think it is.

Take care.

Joe

[Malek@MRF]

These transmissions are fully synchronized. You do not need to learn how to double clutch on this car. Lets put it this way, all modern MT's are fully synchronized.

[longodj]

Wouldn't it make sense to take some stress of the synchros whenever possible? I double clutch on all downshifts...

[Malek@MRF]

Originally Posted by longodj

Wouldn't it make sense to take some stress of the synchros whenever possible? I double clutch on all downshifts...

you should rev-match on all downshifts, not double clutch.

Again, these transmissions and all other MT transmissions over many years ago are synchronized. The newer transmissions are even better with their synchro-mesh design and double clutching is completely unnecessary.

[longodj]

I still think I'll double clutch...you rev match while double clutching...I see no reason not to, it takes one extra step.

[Malek@MRF]

Originally Posted by longodj

I still think I'll double clutch...you rev match while double clutching...I see no reason not to, it takes one extra step.

Whats the point when the synchromesh design was implemented to remove that "one extra step"?

Suit yourself I guess.

[judec]

well, just think about it this way - the step and all the other more advanced ATs or robotised MTs revmatch during downshifts for U, now what do U thnk, why is that?

[kwakr738]

So you clutch on the shift down to neutral, then you clutch on the shift into lower gear. Now I know what a double clutch is. If the engine speed is at an extremely different speed from the shaft, double clutching will help make the shift down easier.

[cycler]

Originally Posted by kwakr738

So you clutch on the shift down to neutral, then you clutch on the shift into lower gear. Now I know what a double clutch is. If the engine speed is at an extremely different speed from the shaft, double clutching will help make the shift down easier.

Ok this is what i do and you guys tell me if its the same.
As Im breaking I hit the breaks and usually the clutch at the same time then i drop in into a lower gear. or i break.....then just drop it into a lower gear

[kwakr738]

Originally Posted by cycler

Ok this is what i do and you guys tell me if its the same.
As Im breaking I hit the breaks and usually the clutch at the same time then i drop in into a lower gear. or i break.....then just drop it into a lower gear

Yep that's what I been doing. There is no need to double clutch as all modern cars have a syncromesh.

[Haretakis]

Clutch in then neutral clutch out rev match then clutch in and put it lower gear. I have made this a habit of mine, it really isn't any slower and it seems much smoother to me. I think it is a nice way to alleviate some drivetrain stress espeically when I am driving hard or wanna go from 6 to 3rd on the highway or something.

Plus it's fun, if I wanted to do as little work as possible I would have bought an automatic....

[AWD Addict]

Originally Posted by Malekreza11

These transmissions are fully synchronized. You do not need to learn how to double clutch on this car. Lets put it this way, all modern MT's are fully synchronized.

It's nice for rev matching during downshifting. Much smoother ride for passengers, and less wear on the synchros too! It's best on exit ramps from the freeway, because the car is actually well balanced into the turn rather than front loaded from an rough downshift.


A good safe point is to rev about 1000rpms up for the next gear down during downshifting.

[nj335i]

I double-clutch only when downshifting 2 or more gears. Seems smoother to me, but that may just be my driving style.

[Hegemony]

Learn to heel-toe instead.

To me at least, double-clutching always seemed to be the method of choice when the position of the throttle and brake made it nearly impossible to heel-toe. This isn't a problem in BMW's.

[judec]

Originally Posted by kwakr738

Yep that's what I been doing. There is no need to double clutch as all modern cars have a syncromesh.

U obviously don't know what U're talking about. Elaborate on the topic a little more.

"all modern cars have a syncromesh" - yes, and that synchromesh doesn't wear, right? and that synchromesh prevents stresses on the drivetrain, right? c'mon, put some effort in studying the topic before making statements like this!

your holly syncromesh prevents the gear-wheels to grind each other while shifting while not revmatched. But it has its price - friction causes the synchros to wear and the friction forces while matching the rpm of gear-wheels stresses the whole drivetrain. Such a kick especially in a curve can throw your whole car out of ballance, man. STUDY!

[kwakr738]

Originally Posted by judec

U obviously don't know what U're talking about. Elaborate on the topic a little more.

"all modern cars have a syncromesh" - yes, and that synchromesh doesn't wear, right? and that synchromesh prevents stresses on the drivetrain, right? c'mon, put some effort in studying the topic before making statements like this!

your holly syncromesh prevents the gear-wheels to grind each other while shifting while not revmatched. But it has its price - friction causes the synchros to wear and the friction forces while matching the rpm of gear-wheels stresses the whole drivetrain. Such a kick especially in a curve can throw your whole car out of ballance, man. STUDY!

You obviously are an asshole in real life too. Exactly what was incorrect about that statement?

[Malek@MRF]

Originally Posted by judec

U obviously don't know what U're talking about. Elaborate on the topic a little more.

"all modern cars have a syncromesh" - yes, and that synchromesh doesn't wear, right? and that synchromesh prevents stresses on the drivetrain, right? c'mon, put some effort in studying the topic before making statements like this!

your holly syncromesh prevents the gear-wheels to grind each other while shifting while not revmatched. But it has its price - friction causes the synchros to wear and the friction forces while matching the rpm of gear-wheels stresses the whole drivetrain. Such a kick especially in a curve can throw your whole car out of ballance, man. STUDY!

I don't mean to instigate an argument, but this is misleading information, mainly because it has no basis for truth.

P.S. You don't need to double clutch to rev-match. That's the whole purpose of a synchronized transmission. Out of all the cars I have built, tuned and owned, no transmission has ever failed because of not double clutching. If one is going to make how the automated manuals (i.e. SMGII) revmatch, the system does NOT double clutch. The rev-match occurs on the one and only depression of the clutch in between gear shifts. Leave the STEPtronic argument out of this. Automatic tranny's operate on a completely different scale than MT's. Apples to oranges comparison.

Leave the double clutch talk to the F&F movies.

[longodj]

This just sounds like the logic is missing a bit. OK yes, in F&F they say "granny shifting not double clutching like you should". That's retarded because they are UPSHIFTING. However when downshifting, synchromesh or no synchromesh, there's some stress, there's some wear. Double clutch downshifting takes stress off the synchromesh, and the synchromesh takes stress off the gears. Hell double clutch heel toe if you want... I just don't see a downside??

[oct1285]

why are you people double clutching when you can just rev match and get the same end result?

[Haretakis]

I do double clutch heel toe, you guys don't know what you are missing haha. No need to argue, some prefer to work a little bit. To me the manual transmission is a novelty at this point. Autos are shifting ridiculously fast now and the SMG or DCT types even faster. Driving manual is fun for the sake of more driver involvement and for me that means double cluthing, heel toeing or both at once.

[PiperD]

It's not the same end result. Double-clutching speeds up the intermediate shaft, rev matching does not.

Rev matching removes abrupt driveline changes, which is critical when you're entering a corner at speed. Double-clutching makes it easier to engage a lower gear.

People are arguing the need to double-clutch in a modern transmission with synchromesh.