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Can some of you wise people give me an idea what double clutching is all about and how it is done. What are the benefits etc.

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Double de-clutching, as I understand it, was a method used back in the days when syncromesh wasn't around. It's a method which allows smooth downchanges, allowing for fast, smooth driving.

I don't think it's used anymore, since the advent of syncromesh - Heal and Toe is the modern Holy Grail!

Driving fast is all about being smooooooth!
 

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It's not really about fast gear changing, it's actually about reducing wear and tear on the engine. I asked this when I went on my ferrari experience day recently and he said there's no advantage to it in a modern car.
 

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Heel and toeing is the method used to double de-clutch while braking. The brake is operated by the ball of the right foot while the accelerater is operated by the heel, or more usually the outside edge of the same foot, leaving the left foot free to operate the clutch. Double de-clutching involves releasing the clutch pedal momentarilly, while changing down as the lever passes through neutral. At the same time the throttle is blipped to increase the engine speed to what it will be when the lower gear is engaged. The clutch is then depressed again as the lever is pushed into the lower gear position. With practice, the change can be made faster and smoother than without double de-clutching, so I would disagree that there is no advantage to it, and if you get it dead right, it is very satisfying. [:O] Paddle change type auto's, such as Ferrari's F1, do it electronicly.
 

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Quote: posted by talk-torque on 06/09/2004 23:38:27

Heel and toeing is the method used to double de-clutch while braking.

Not exactly no... You're quite right that you can heel and toe while you double declutch and yes I can do it very precisely and to great effect, but..... Several years ago I spent an hour in a 300 bhp race prepared Sierra Cosworth, circulating Knockhill with Ian Forrest in the passenger seat. He observed that my double declutching, heel and toe downchanges were "fabulous" and "probably the best he'd ever seen", but he was quite clear that although the heel and toe part was necessary, the double declutching part wasn't and in fact was losing me just that vital bit of time on the way into corners, at which point someone would nip up the inside of me on the brakes.

The moral of this is that I've unlearned the double declutching bit and now heel and toe my way home from work, on B road heaven, every night. Brake, dip clutch and blip throttle with outside edge of right foot while sliding the rifle bolt action of the 6 speed box down a gear.
 

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AFAIK the only reson to double de-clutch would be when using a gearbox without syncro. In some very old motors/trucks I've driven there has been a need to double de-clutch going up the gears too.

Schtum is right, 'Heeling and toeing' is a method of matching engine revs when changing down on the brakes. In high powered/race cars when braking hard and changing down if you don't blip the throttle the engine braking can lock the wheels momentarily thus unsettling the car and causing a spin.
 

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Schtum - Good point, well put. I think I'm a bit old to "unlearn" double de-clutching, and I don't usually need to save the hundredths of seconds we're talking here, but I shall have a go, on the way home, tonight.

By the way, I learnt to drive in a 3-speed Ford 100E, with no syncr on bottom gear. So little power that you needed bottom up some hills, and the only way to get into it, without stopping, was to double de-clutch.
 

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One of mine was a '72 MG Midget no synchro on first too! You'd have thought that they'd put it on by then, but no, the famous british motor industry was still behind!
 

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Quote: posted by talk-torque on 10/09/2004 12:12:36

Schtum - Good point, well put. I think I'm a bit old to "unlearn" double de-clutching, and I don't usually need to save the hundredths of seconds we're talking here, but I shall have a go, on the way home, tonight.

If you're really 101, you might just be right. That would make me just over half your age and I managed to retrain myself.....
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By the way, I learnt to drive in a 3-speed Ford 100E, with no syncr on bottom gear. So little power that you needed bottom up some hills, and the only way to get into it, without stopping, was to double de-clutch.

I began in a three speed Renault Dauphine. At least I didn't have to contend with vacuum operated wipers like the 100E....an important consideration in Scotland....only the Dauphine's interesting handling.
 

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I may be wrong on this but I thought the software on the golf prevented heel and toeing? i.e. if you put your foot on the accelerator whilst on the brake nothing happens.
 

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Quote: posted by Gti Fly on 10/09/2004 19:02:55

You can heal (sic) and toe in a DBW golf. The ECU will only intervene if you're stupid enough to stamp on both pedals hard and long enough.

That's not stupid. That's called left foot braking and is another very useful technique. We can blame the Merkins and the "unintended acceleration"
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lawsuits which Audi had to contend with in the early 80's, when Merkins pressed both pedals at once, for that little safety feaure built into the ECU. I believe that the quick and dirty fix is to disconnect the brake light switch on the brake pedal. I can't remember if it's possible to disable it with VAG COM. There was a great deal of discussion about it over on Fred's at one time.
 

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Schtum, pardon my ignorance, but what's "Fred's"?

We had that same discussion on here, actually. I remember nearly going through the windscreen trying to brake gently with my left foot, while being progressively thrown further forward in the seat by the rapidly increasing g force. As has been said, the system will let you blip the throttle while braking, but anything more than a blip is killed.
 

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guys, i thought double clutching was the name given to when you're travelling at a constant speed, and u want to floor it all of a sudden... to get a better takeoff from whatever speed you're doing, the clutch should be momentarily pressed and depressed (as in under a second) while at the same time keeping you're foot on the gas... u then just launch forwards...

i've read about downshifting and heal-and-toe or whatever other names they both go under... the downshifting will be when you want to go down into a lower gear but before doing so, u increase ur revs so that there isn't a jolt in the gear change and thus a much smoother ride, this isn't too hard to do, it just takes a bit of practice. heal-and-toe is pretty much doing this while turning... i can't do this but i kinda know how it's meant to work.... still practising.
 

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Mokey, I think this is called dipping the clutch, keeps the engine "on the cam" ie. in the power band, so that the car doesn't bog down.
 

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You don't need double de clutching in modern cars, Well not unless you've got a worn or sticking syncro ring. Or your into racing.

It's worth knowing how to double de-clutch.

How many times have you driven a vehicle that wouldn't go straight into first gear when you've reversed out of somewhere?? A quick blip in netural to spin the sycncros can work the magic.
 

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As a learner driver my dad taught me to blip the throttle on the downshift and I have been doing it ever since. There's nothing worse than changing down, eg to overtake and the car slows down. Adding a couple of hundred rpm makes the change soooo smooth.

This is good for me as I use engine braking a lot. The combination of engine and brakes to slow a car increases fuel economy and brake longevity. My car's done 40k and the front pads will probably do another 40k before they need replacing.
 
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