Can you track junkies help me double-clutch properly?

I have read the many how to's and seen many videos about double-clutching however, I am still not sure I am doing it properly.

This is my procedure (say going from 6th to 4th gear):
While the accelerator is pressed...
1) Let go of the accelerator
2) Press the clutch pedal
3) Move the shifter to neutral
4) Let go of the clutch pedal
5) Press on the accelerator quickly until the RPMs hit a number I expect 4th gear to be in
6) Let go of the accelerator
7) Press the clutch pedal
8) Shift to 4th
9) Let go of the clutch pedal while pressing on the accelerator

Question is, do you guys ever let go of the accelerator or do you leave it pressed and press it further down when matching the revs? Thanks!

 

^not sure what you are trying to do here...but if you mean heel/toeing to revmatch for downshifting...it is more like:

6th gear

clutch-in while shifting and a little blip to the throttle as the motion is progressing.

 

Why are you double-clutching in a car with synchronized gears? All you need to do is blip the throttle, while the clutch is depressed, as you're moving the lever between gears to match the engine revs to the transaxle speed. Unless of course your synchros are blown or you just enjoy a quaint piece of history, I don't think you're doing yourself any favors by shifting this way.

 

Here's how I do it:

1) Apply light pressure on the shift knob pulling it out of the gate, still on the throttle
2) Let go of the accelerator and press the clutch pedal at the same time
3) The shifter pops to neutral due to that light pressure
4) Let go of the clutch pedal about 2/3 of the way while stabbing the throttle until the RPMs hit a number I expect 4th gear to be in, also move the shifter to just above/below the gate I'm going to shift to
5) Keep enough pressure on the throttle to maintain desired RPM
6) Press the clutch pedal
7) Shift to 4th
8) Let go of the clutch pedal and the throttle at the same time and continue braking

I do this by feel/sound, not by watching the tach. With enough practice you can get reliably close to the correct RPM. You should be able to do this part way through braking so that you don't have to get immediately on the throttle.

 

Thank you.

"5) Keep enough pressure on the throttle to maintain desired RPM"
- I think this is my problem. I let go of the throttle after blipping it instead of keeping the pressure on. This results in the RPM dropping back down negating the rev-match.

"8) Let go of the clutch pedal and the throttle at the same time and continue braking"
- I am assuming that if I am just downshifting for acceleration and not braking then this would be "let go of the clutch pedal AND CONTINUE THE THROTTLE."


Thanks again!

 

I see. In that case, I floor the throttle just as I'm letting off the clutch. Getting a perfect rev-match is less critical when accelerating so I'm a little sloppier when doing this. This is usually only done when passing on the highway so the utmost speed and precision isn't required.

Ludedude is right - you definitely don't NEED to double clutch. I do enjoy this 'quaint piece of history' and the daily practice has done me well when I hopped in cars (some Formula cars) and trucks (usually big stuff) that require it. Once you get enough practice it's no slower than downshifting without a double clutch while braking - and it definitely reduces wear on the syncros. Doubtful that this wear will amount to anything in 10 years of driving though...

Some successful racers/autocrossers don't rev-match at all, they just let the clutch slip speed up the engine instead of using the throttle. Those guys claim that rev-matching is unnecessary as well.

 

Trucks, I can see. The only formula cars I've been in required rev-matching on the downshift, but a simple heel-toe operation took care of that under braking. No rev matching on the upshifts needed in either the formula car or the Radical (it has a sequential box) that I drove.

It is a quaint piece of history

 

[QUOTE=captain_pants,Dec 2 2007, 11:14 AM] Some successful racers/autocrossers don't rev-match at all, they just let the clutch slip speed up the engine instead of using the throttle.

 

Rev matching is necessary, but you don't need to double-clutch to do so

 

Again - no one, including me, is saying that double clutching downshifts is necessary! But it does make downshifts to 1st drop into gear smoother in every automobile I've driven. It helps any vehicle with weak or non-existent syncros and cannot hurt any vehicle with good syncros. Technically you don't NEED to use the clutch either, but I like using it in case I don't get the rev-match right.

Heck, some street Subarus run dog-boxes with no syncros! That's a little crazy for me, but it sure is nice to be able to hop in any car and drive it. You'd be fool to think that you can just hop in a vehicle that has no syncros and just pick up double-clutching immediately. The OP may want practice, or is just plain interested in quaint history.

Did anyone mention rev-matching on upshifts? Surprisingly, there hasn't been the obligatory dumb 2F2F quote in this thread yet...

How could you double-clutch with a sequential box? You only pass through neutral briefly on the way to the next gear.