I thought this deserves it's own post.

- Double clutching when the car is cold helps the transmission shift smoothly.

- When just crusing in traffic you can also do this, or blip the throttle a bit while changing gears.

- I recently learned hard downshifts into 1st when autocrossing requires blipping the throttle - standard heal-toe I know, but RETED pointed this out to me.

- If you always have problems with very notchy or hard downshifts, try synthetic tranny fluid/gear oil. I use RedLine gear oil in my tranny & diff. Other's use Royal Purple (the guys who patented purple bottles).

 

Also try bleeding your clutch hydralics. This can make a world of difference.

 

Meh my 2nd gear synchros are about gone, shiftign into second w/o double clutching is becoming less and less of an option...

 

my understanding of double clutching is: clutch in, shift to neutral, clutch out, clutch in, shift into gear, clutch out. is this right? i use this technique on older cars that have no syncromesh or cars with worn syncro's.

 

 

I double clutch all the time, but only on weekdays...

BECAUSE I DRIVE A TRUCK! The only damn vehicles left in the world that actually require double clutching. The Kenworth I drive sometimes at work has the world's oldest Road Ranger tranny on it and with that comes straight cut gears and a need to double clutch. Your tranny has synchros for a reason, quite using the term unless you also use terms like smokey, convoy, long haul, tractor, combo, tex, anything of the like.

 

i heard that double clutching if done smoothly and fast enough can be better/faster when driving fast (changing gears at redline). i hate when people misuse the term too though, and think they know what they are talking about. this little chinese kid in one of my classes when i was in school last year thought double clutching was when your just driving around and you want to floor it, but first you push in the clutch and rev it up real high then drop it. apparently he has also done a b16 swap with tranny into his 93-95 civic hatch. i doubt it though.

 

Double clutching will never be quicker than doing it normally, and it does not make the gearchange any smoother if you have decent synchros. I have no idea why anyone would bother when we have modern gearboxes specifically designed so we don't have to. My synchros are all shot to hell and I still wouldn't waste my time doing this.

 

Maybe I was using the wrong term but when refuring to double clutching I mean rev matching, so that when you downshift you get the engine up to RPM's it should be at for that gear at that speed.

So what I do is; clutch in, shift to neutral, clutch out, blip throttle, clutch in, shift into gear, clutch out.

When I get it right it's a whole lot smoother then just doing a normal shift, it avoids that lurch that happens when the engine is getting up to speed.

 

fun fun fun.. btw did Royal Purple really patented purple bottles?

edit: laggy forum!

 

there is a way easier way to do that. clutch in, blip throttle, shift, clutch out.

 

I think a lot of people are using double clutching to describe rev matching, which can be very helpful on a course. That is if you are downshifting and turning at the same time, rev matching will keep your car from lurching to match revs itself. If you do blip the throttle and get the motor up to speed with the drivetrain, you have a better chance of not losing control of the vehicle.

 

my second gear synchros is shot to hell. you can say whatever you want about it being arcane, unneccisary etc. i know that at anything over 3k rpm, the stick WILL NOT go into 2nd without double clutching. sure its not as fast as if i haddecent synchros, but its still faster than waiting 5+ secondsfor the rpm and speed to drop enough for the gear to finaly catch, or settle for 3rd gear when i realy need second.

this is only for downshiftingfor acceleration. anything else, and the synchro is still just strong enough to not grind.

i need to work on my heel toe for braking tho. am i the only one who finds the pedal placement a little inconvenient for that? i mean my thigh keeps hitting the wheel and my heel hits the tunnel before it can rotate out enough.......

 

thats the one that i use... i just learned manual and while learning i used that technique... but i was thinking, is it bad? like if u press the gas right after the clutch, dont u burn the clutch while pressing it? or it doesnt make a difference?

 

I would like to throw in my experience having burnt a clutch in a little more than two months "canyon racing". Which basically means a lot of braking... rather go in a little too slow and accel out than go in too fast and DIE.

Double clutching, never did it EXCEPT for downshifting into FIRST. Jesus what a pain that was. Generally synchros do their job, they were burnt to hell as well, but when you do hard shifting at nearly every shift, it's gonna happen.

Rev matching... EVERY TIME I DOWNSHIFTED. Every gear. This is what I believe the culprit was no less... see even though I'm good at rev match downshifting, you can never get it perfect... and since you're relying so heavily on it to slow you down (MOST of the reason you're downshifting into high RPMs... people that tell you it's mostly to have acceleration out don't aren't wrong but the braking help is a thousand times more useful than being in the high rpms for accel... rev matching helps both, but without downshifts like that I'd lengthen all my stopping distances by 1/4.. that's a lot) anyway, relying on it to slow you down is putting heavy stress on the clutch. It wasn't made to be used as a brake. That's what racing clutches are made for.

So yeah, rev matching is great... but the problem is... I assumed because I was good at it it wasn't hurting the clutch too much. I didn't slip the clutch when I matched and let it go, it almost always caught perfectly... but it's a high stress bite. So rev matching is good as long as it's not so much to slow yourself down as to finish slowing you down after you use your regular brakes. Using the clutch as a brake is bad news. -_-

Later.

 

well most of the time when i rev match while downshifting, its smooth, so its no stress to the clutch or tranny right?

 

Just power shift it!!!

 

I double clutch just for fun
when I'm on a track/autox....no time to double clutch

 

10-4 Good Buddy.

 

has anyone heard of turbo shifting? iunno if it was just my friend being a stupid *** again but he said if while you shift you keep giving it a little gas (so the turbo spools) then its good in a turbo car. im guessing this would be useful while accelerating.

 

double clutching: pumping the clutch pedal like a drunken monkey 9 or 10 times in between gears. good for; looking like an idiot, driving big rigs.

rev matching: making sure your engine is running at an appropriate speed for the gear you're about to grab. good for; minimizing clutch wear, smoother and safer power transfer from motor to pavement.

NOt THe SAmE THING!!!!!

sorry guys, it just erks me to death that the two terms seem inseperable in conversation. you can double clutch without revmatching. you can revmatch without double clutching.

 

i assume what u saying is :
rev match = good
double clutch = bad

 

not that dblcltching is bad, but it's not a performance driving technique. this thread has already covered the specific applications where it's useful (a seriously effed up tranny or a tranny which has no synchros at all). rev matching is an absolute necessity for good driving no matter what.

 

what about RPM shifting... where you don't even use the clutch in the first place? A friend does that with a B20 CRX that runs high 11's... and he runs high 11's with it... I use it sometimes, especially during daily driving if there isn't TOO much traffic... its a lot more fun that using the clutch... and if u get good at it it sure beats the hell out of REV MATCHING... <--thats a true performance driving technique

 

Rev-match - matching the revs to each gear. A very useful technique, regardless. Done right, it saves your clutch b/c you are matching gear/clutch/flywheel(engine) speeds all at once.

Double-clutching - a technique made obsolete by modern day syncros. Only useful with a effed up syncros. But if done correctly, downshifting can be even smoother. Pointless technique? Hardly, but it's not a very useful technique in today's age. So don't be hasten to call it 'stoopid'.

Heel-n-toe - the ability to brake and match your revs to keep the engine in its powerband while slowing down so that you can ready yourself after the apex. It incorporates the Rev-match technique.

RPM-shifting - shifting w/o a clutch - requires that you master the rev-match technique perfectly for the downshifts, and that you upshift at the precise moment everything lines up.

Any/all of these techniques, if mastered, will decrease clutch wear significantly. My Honda after 70k on the clutch, still had plenty of meat left, that I decided to return the new clutch and continue using the 70k clutch (engine blew a rod bearing). Although with Dbl/clutching, you will see a slight increase in wear on the throwout bearing, b/c you are using the clutch 2x as much.

David