Contour Enthusiasts Group Archives Forums Modifications Duratec Performance How do you double clutch ......

Randy Pobst a 5 time SCCA National AutoX champ AND a ALMS Porsche driver would beg to differ.

He double-clutch downshifts even with syncros... NOW he doesn't downshift all gears.. he gets thru the brake zone, slows down and then double clutches and picks the proper gear for the corner exit.

It isn't a hard thing to learn and isn't a bad skill to have.

BTW it will save the syncros if done properly.

Maybe it's more the 'heel/toe' driving technique rather
than double clutching....

Originally posted by TedS:

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Randy Pobst a 5 time SCCA National AutoX champ AND a ALMS Porsche driver would beg to differ.

He double-clutch downshifts even with syncros... NOW he doesn't downshift all gears.. he gets thru the brake zone, slows down and then double clutches and picks the proper gear for the corner exit.

It isn't a hard thing to learn and isn't a bad skill to have.

BTW it will save the syncros if done properly.

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Why won't he just heel-toe to match revs to wheel speed?

Double Clutching is from the days of YOR when trannies didnt have syncros. Totaly pointless in any car with a sycronized transmission.

Now there is a modern double clutching technique that is EXTREEMLY difficult to pull off, but does significantly improve trap times, but before I go on, DO NOT TRY THIS AT HOME! IT IS A TECHNIQUE FOR PROFESSIONAL RACING ONLY, AND REQUIRES A LOT OF PRACTICE ON A CAR YOU DONT CARE ABOUT THE DRIVETRAIN.

Now that the disclaimer is out of the way,

Drag double clutching (this was started in dragsters) consists of a combination of speed shifting, combined with a controlled slip (BTW, in moden funny cars, and some stock D cars, this is technique is actually done by a computer controlled clutch).

A step by step would go something like this:

Dump at prefered RPM, run to redline, when shifting do NOT let off the gas (this is the speed shifting part) but when you let the clutch up, let it up slowly on purpose so that the engine keeps a slightly higher RPM than if you just slammed it into the next gear.

Having said this, I re-iterate, DO NOT DO THIS!!! YOU WILL TEAR YOUR CAR APART! a public road car IS NOT built to handle this sort of shifting technique.

BTW, this is called a double clutch because if you shift fast enough, you never fully enguage the clutch, so in effect you are enguaging it twice or more per shift as you 'float' the pedal up and down to keep the RPMS up.

PLEASE PLEASE DONT TRY THIS... I dont want to hear any 'Countour Trannie died when double clutching' topics, ok?

my good friend with a 350hp+ wrx double clutches his while he races, and i can tell you riding with him before n after he mastered it, its a good thing if you do it right... basically what he does is bang the clutch twice, feather the gas in between as in hit clutch, let out, hit gas, push in let out.... the trick is to get the timing down so that your making the shift at the right time.. its complicated especially in road racing while your bodys being tugged around by gravity and centrivical forces... but in my humble opinion it helps

course i have an atx so i just smash the gas :P

Heel Toe shifting is double clutch shifting. Just two ways to say the same thing

You pop the clutch out and rev-match, then put the clutch back in to change gears...


Sequence.

1)depress clutch
2)move shift lever to Neutral
3)release clutch
4)rev-match to engine to speed/gear
5)depress clutch
6)select gear
7)release clutch


if done properly it is fairly quick. I can get from 5th to 2nd in a second and a half or so... maybe less... Of course you could just choose the proper gear and not work your way down all gears.

What's the point of releasing the clutch and puttingthe car into neutral? Why not keep the clutch in as you bring the RPMs up and then release?

Popping the clutch in neutral syncs the gears. The tranny syncros don't have to work as hard/at all.

I find that it makes upshifting easier

I attribute it to the high miles on my car but in the winter when the car is still fairly cold, within a few miles of hime still, it is dificult to get first gear and sometimes second. By letting the clutch out for a second in neutral it makes the shift easier.

This also maybe in part to the fact that the gears are used to oil the transmission. So if the gears are not turningthe trans isn't being oiled. - from my understanding

ok, so isn't double clutch upshifting rather pointless unless you're really not using the clutch much at all?i was under the impression that power shifting was the way to go for faster upshifts. how hard is this on your car, if you don't do it too often?