Driving question

[Boost91Talon]

I didnt know where to put this question but i was wondering when you drop a gear should you give a little rev when you push the clutch in and then let it fly and floor it? or should you just put the clutch in shift and then let it fly and floor it? does that rev hurt or even make a difference?

 

[brpeclipse]

In a street application, when you downshift you want to rev before you engage your clutch just a bit so it doesn't take all the"weight" of all the rotational mass. This way tends to take more time but after you get used to it, you can do it very quickly. Its called "rev matching". HTH

 

[Boost91Talon]

thanks for the reply

 

[Defiant]

If you're not going to do a real "double-clutch", then a "double-kick" (rev-match) is an okay but distant second-best. It won't do anything for the synchros, but it will be good for the rest of the driveline, and for keeping tire adhesion. The idea is to get the crank up to the speed it'll be turning when you let the clutch out, to save the tires, CV joints, gearbox and clutch from having to carry the loads: to do it properly, you give the engine a quick goose when the clutch pedal's down, just before releasing it. With only a little practice it becomes second-nature, and you quickly learn just how much to blip the gas.

To double-clutch, you do pretty much the same thing, except that you do it twice: Press in clutch, shift to neutral, let out the clutch (so that the blip also speeds up the transmission guts) blip the gas, press in the clutch and shift to lower gear, let out the clutch. It's a lot easier to do than to read about.

To make it a heel-and-toe downshift, you do the above, but while your foot's on the brakes: you do it by rolling your ankle so that you can blip the throttle while braking. Again, easier done than imagined, although power brakes make it a pain in the ass. It was gravy in the days before brake boosting.

 

[Tallen]

FYI theres NO NEED to double clutch in a car with a syncro'd tranny, just wasted time shifting and 2x the use on the clutch....unless your syncros are waxed or your driving an old muscle car.

 

[tsunari]

This explains it all:
http://www.turnfast.com/tech_driving/driving_heeltoe.lasso

 

[Defiant]

Originally posted by Tallen
FYI theres NO NEED to double clutch in a car with a syncro'd tranny, just wasted time shifting and 2x the use on the clutch....unless your syncros are waxed or your driving an old muscle car.

Yeah. Do a search here for "second gear grind" and tell me there's no need. EVERY transmission will have an easier time if you either
a)Double clutch
or
b)Don't downshift at speed, and use the brakes instead.

This applies to every vehicle ever rolled, from Isettas to Duesenbergs. And especially to the DSMs.

FYI.