Heel&Toe question

[richard]

Is double clutching necessary while heel and toe shifting? The way I learned was to begin braking, push in clutch, blip throttle while going through neutral to lower gear, release clutch. I have a British friend who says what you are supposed to do is begin braking, push in clutch, shift to neutral, let out clutch, blip throttle, push in clutch, shift to lower gear, release clutch. I sometimes do the double declutch when downshifting going straight down the road, but it sounds hard to do it fast enough when approaching a corner.

[swchang]

Is double clutching necessary while heel and toe shifting? The way I learned was to begin braking, push in clutch, blip throttle while going through neutral to lower gear, release clutch. I have a British friend who says what you are supposed to do is begin braking, push in clutch, shift to neutral, let out clutch, blip throttle, push in clutch, shift to lower gear, release clutch. I sometimes do the double declutch when downshifting going straight down the road, but it sounds hard to do it fast enough when approaching a corner.

I asked this same question a little while ago. Many would say no, but they would also say that double clutching is unnecessary. Purists like Pinecone who think double clutching is necessary and/or fun and/or proper would say yes. I like to listen to Pinecone, so I just do what he says. ;)

[teh_jev]

Personally, I don't see a point of it ever. I've always driven sticks and never double clutched anything but some old moving van that had to get moved one day. Talk about a PITA, IMO anyway.

[Andrew*Debbie]

Is double clutching necessary while heel and toe shifting?


Necessary? No.

You can just hit the throttle to rev match while shifting, then come back off the clutch.

On a car with good sychros, I get a faster shift this way then if I double clutch.


On my old Fiat, with crappy 1st and 2nd synchros, I would always double-clutch going into those gears. Going from 4 to 2 into a good corner, I'd usally just leave the gas pedal floored through the entire process. It was the only way I could get a good downshift at speed. Yeah it went into the red sometimes. Once or twice I glanced down to see the tach past the red band and sitting on the peg :yikes: With about 85 HP on a good day, I needed the downshift to get any pull through the turn.

[FenPhen]

Personally, I don't see a point of it ever.
The more aggressive the shift, the more double-clutching is beneficial and necessary, perhaps say a blip close to redline to go into a corner if you're racing, or skipping several gears.

(That being said, I don't double-clutch, except for the sake of trying it out.)

[Scott ZHP]

Pretty much agree with everything stated, except I think the proper term is double DE clutching.

My first MG had a non-synchro first gear (aka crashbox), this was required to downshift back to first.

[Jeff_DML]

agree with everyone else :D

this website has some info on what happens

http://auto.howstuffworks.com/transmission4.htm

[teh_jev]

The more aggressive the shift, the more double-clutching is beneficial and necessary, perhaps say a blip close to redline to go into a corner if you're racing, or skipping several gears.

(That being said, I don't double-clutch, except for the sake of trying it out.)I've always done that w/out the DC. Works easier for me. Press clutch, quick blip, ram stick home into gear and dump clutch, floor gas.

[wingspan]

With about 85 HP on a good day, I needed the downshift to get any pull through the turn.

Bwahahaha! You had lots of power! Try 76 HP! :D


(course with only 1400 pounds to lug around...)

[Pinecone]

Necessary? No.

You can just hit the throttle to rev match while shifting, then come back off the clutch.

On a car with good sychros, I get a faster shift this way then if I double clutch.


On my old Fiat, with crappy 1st and 2nd synchros, I would always double-clutch going into those gears. Going from 4 to 2 into a good corner, I'd usally just leave the gas pedal floored through the entire process. It was the only way I could get a good downshift at speed. Yeah it went into the red sometimes. Once or twice I glanced down to see the tach past the red band and sitting on the peg :yikes: With about 85 HP on a good day, I needed the downshift to get any pull through the turn.

Man, must have been a 124. I used to autocross an 850. Maybe 60 hp on a GOOD day.

First try a search. Several LONG threads about it.

But to restate.

Double clutching is not required for modern gearboxes. However doing this WILL reduce the synchro wear and the stress on other components. Plus it is cool and another skill to have for when teh synchros go out a long way from home.

For racing you don't even use the clutch to get out of gear into neutral for the fastest shifts. But this is very hard to do unless you are really pushing.

Do what you prefer, but for the least wear and tear, for most driving double clutch. When you are dirving on the ragged edge, you do what works best to least upset your car and your concentration.

And yes, it is most proper to say double de-clutch, but nobody but seriously ana1 a33holes bother to do so, or Brits. :) Actually after you de-clutch, you clutch, so either would probably be right. BTW do you extend a pinky when drinking your tea? :)

[AndDown]

Is double clutching necessary while heel and toe shifting? The way I learned was to begin braking, push in clutch, blip throttle while going through neutral to lower gear, release clutch. I have a British friend who says what you are supposed to do is begin braking, push in clutch, shift to neutral, let out clutch, blip throttle, push in clutch, shift to lower gear, release clutch. I sometimes do the double declutch when downshifting going straight down the road, but it sounds hard to do it fast enough when approaching a corner.


Richard, you might have already seen this link, but in the event you haven't:
http://www.bmwm5.com/greg/school/

But then again, maybe this still doesn't answer your question. :dunno:

[FenPhen]

Works easier for me. Press clutch, quick blip, ram stick home into gear and dump clutch, floor gas.
Right, if you want to brute force it, you can. But the whole point of a double-clutch shift is so you're not "ramming" the tranny into gear. The reason you have to ram it is because the speed of the gearbox does not match your wheel speed with the target gear, and the way these two pieces are synchronized is with the synchros. Either way you do it, the work has to come from somewhere, and it's better for your transmission if you help it and bad if you have to force it.

This idea is the same as the idea behind why you rev-match on a downshift.

[Pinecone]

Not exactly, you reve match on the downshift to avoid having the rear wheels break traction and making you spin.

TRUST me. :) Turn 1 VIR, nice dice in a Spec Racer, 5 - 4 fine, 4- 3 watching the other car and trying to give him room, but not too much room, not enough blip and instantly I am backing off the course.

Yes, the rev match does help clutch life, but the real reason is not upsetting the balance of the car.

[teh_jev]

Right, if you want to brute force it, you can. But the whole point of a double-clutch shift is so you're not "ramming" the tranny into gear. The reason you have to ram it is because the speed of the gearbox does not match your wheel speed with the target gear, and the way these two pieces are synchronized is with the synchros. Either way you do it, the work has to come from somewhere, and it's better for your transmission if you help it and bad if you have to force it.

This idea is the same as the idea behind why you rev-match on a downshift.Well, I didn't literally mean "ram" it like it was hard or anything. I dunno, just never driven a car where i've ever had problems w/ rev matching or anything. Maybe I'm just a natural, lol.

[FenPhen]

Yes, the rev match does help clutch life, but the real reason is not upsetting the balance of the car.
Yes, you're right, rev-matching is really about not upsetting the car, and during less aggressive driving, to avoid lurching. Double-clutching is not critical to the dynamics of the car, but can help the transmission.