you still have to wait for the revs to spin up, while im watching the rpms climb im working the clutch back and forth. I notice no difference in time. between true double clutching and the other thing. Besides, I usually am double clutching while heel and toe'ing for a turn, so I'm slowing down anyway.

By double clutching the layshaft is at the proper speed where when you hold the clutch in the layshaft is still spinning down from whatever gear you used to be in. As well as you are making your syncros work just as hard as if you had not double clutched at all because the layshaft goes from 3rd gear to 2nd gear without actually matching the speed of the engine. Lastly you would not be able to downshift a car with dead syncro's unless you double clutched properly.

 

how do u double clutch, and what are syncro?

 

Rev matching and double clutching are only useful for manual transmissions with straight spline gears. Because new transmissions all use helical cut splines, the only thing you're accomplishing is excessive gearbox, pressure plate and flywheel wear.

Helical Gears

 

what year integras use helical cut splines?

 

Just about all cars built after the 70's.

 

So.... my question again, is it bad to double clutch, how should i downshift? I've gone through phases of doing straight downshifts, rev-matching, and now i'm double clutching all the time. What should I do to prolong the life of my clutch and synchros?

 

I think its alot cheaper to replace a throw out bearing than to have your tranny disassembled to replace worn syncros or a worn clutch.

Rooster- Without double clutching or rev matching how do you downshift?

 

Flick then release the accellerator, then shift. The same way my driver's education instructor and driver's training instructor taught me. I asked a bunch of guys about this at the last SCCA event, and everyone of them laughed and told me not to watch the fast and the furious. The whole reason for revmatching and doubleclutching was to mesh up the straight cut gears. Vehicles are designed now so that you don't have to do this... but if you want to, damn the engineers who built them, go for it. :thumbup:

 

ok heres a question for you guys. I am gogin 55 in 5th gear and want to pass say 2 cars in front of me?? I also want to hit 3rd to make it a quick pass. You dont just downshift into 4th or even 3rd with out rev matching that would be plainhard on you and your tranny. Its slowling way down it may even lockthe tires for a second or 2. What i do is hit the lcutch blip the gas pu tin lower gear and then gas on lcutch out like you normally would none of this double xluthing **** that saves no time and everyone is righ ton saying that was for old trucks that didnt have synchros. and I have foudn by rev matching to the right RPMS the downshift feels as smooth as an automatic. Also the mechanic that installed my clutch said rev mathing will do no harm at all.

 

So are you holding the clutch in when you downshift? Or are you shifting without the use of the clutch at all? I still don't understand how you could downshift using that method you described. I would also like to know how you could downshift rapidly from say 5th to 3rd?

I don't know who you talked to at the last SCCA event but if this conversation is going to continue lets get on the same page too:

Rev matching = hitting the gas to bring the RPM's to a certain level- usually to match the speed you are going with a gear you are down shifting into.

Double clutching = downshifting by putting the clutch in, selecting neutral, letting clutch out, REV MATCHING, putting clutch in, selecting gear, letting clutch out.

I'm kinda confused when you say rev matching and double clutching seperately because double clutching incorporates rev matching.

One last thing I was wondering, helical cut gears still use sycnros as far as I know. Dog gears/ straight cut gears generally do not.