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rustytools

Original Poster:

9 posts

14 months

[news] 
Thursday 12th July 2012 quote quote all
Hi everyone.

Here's something that's keeping me awake at night, maybe someone could please explain.

I understand the basic principles of double de clutching and the reasons for doing it (at least I think I do!). I use it regularly. Here is how I was taught how to do it:

Clutch pedal down and take car out of gear
Release clutch pedal whilst still in neutral
Blip throttle to appropriate speed
Clutch pedal down
Select gear
Release clutch pedal

All well and good.

I've recently started to attempt heel and toe, here's the technique I've read and tried using:

Brake
Clutch pedal down (simultaneously braking)
Blip throttle (still braking)
Select gear
Off clutch + brake

But here's what I don't understand. I've read articles that imply you blip the throttle with the clutch pedal down. Is this the correct way of doing it? or am i misunderstanding?

I always thought the point of a heel and toe was just a double de clutch whilst breaking? I thought the whole point of double de-clutching is to blip the throttle off the clutch pedal yet box in neutral so that the engine speeds up the box/layshaft to match the wheel speed ready for next gear change.

Is the correct heel and toe method this way:

Brake
Clutch pedal down
Select neutral
Release clutch pedal
Blip throttle (simultaeously braking)
Clutch pedal down (still braking)
Select gear

I've tried to explain this as best i can. I'm struggling to see why you blip the throttle with the clutch pedal down on heel and toe yet blip the throttle whilst in neutral and off the clutch pedal in double de-clutching.

Am I missing something really obvious?

Cheers

Rusty


rallycross

4,668 posts

106 months

[news] 
Thursday 12th July 2012 quote quote all
Gearboxes and clutches are much better than they used to be.

Heal and toe now is really just smoothing the transition from coming off the throttle onto the brakes, keeping things balanced, older cars may need clutch out so when you blip the throttle gear box revs rise with engine making gear selection easy (matched to engine speed). Modern car with good syncro's and good clutch do not need this.

FisiP1

1,138 posts

22 months

[news] 
Thursday 12th July 2012 quote quote all
Single clutch action(so blip with clutch depressed) is fine for modern cars, some people will claim it is inferior to double clutching still, reasoning that putting the car in neutral re-connects all contact elements that need to be synchronized, and theoretically reduces component wear.

To be perfectly honest you can perform faster and still imperceptible single clutch heel and toe shifts in most modern cars, and you have to be pretty anal to give a damn about the wear argument.

The Moose

9,012 posts

78 months

[news] 
Thursday 12th July 2012 quote quote all
FisiP1 said:
you have to be pretty anal to give a damn about the wear argument.
This is PH we're talking about...after all!

911p

1,855 posts

49 months

[news] 
Thursday 12th July 2012 quote quote all
1) Brake
2) Press clutch down
3) Select lower gear + blip throttle
4) Release clutch
5) Release brake

Repeat steps 2-4 (before easing off brakes) dependant on the amount of downshifts you need to perform. How I personally do it, through I guess everyone has their own technique.
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Dr JonboyG

1,973 posts

108 months

[news] 
Thursday 12th July 2012 quote quote all
rustytools said:
I've tried to explain this as best i can. I'm struggling to see why you blip the throttle with the clutch pedal down on heel and toe yet blip the throttle whilst in neutral and off the clutch pedal in double de-clutching.

Am I missing something really obvious?
Yes. In both cases, the car isn't in gear - that's the important thing, otherwise you couldn't spin the engine up to match the next gear. They do the same thing, but the former is faster because you don't have to faff around as much.

SlipStream77

1,632 posts

60 months

[news] 
Friday 13th July 2012 quote quote all
rustytools said:
I've tried to explain this as best i can. I'm struggling to see why you blip the throttle with the clutch pedal down on heel and toe yet blip the throttle whilst in neutral and off the clutch pedal in double de-clutching.
Double de-clutching is used in cars without syncro' boxes, the way they function requires blipping whilst in neutral.

Heel and toe is used to enable a driver to change down smoothly whilst braking, it simply raises the engine revs so when the clutch is released in the next gear, they are matched with the wheel speed.

To make a double de-clutch downchange whilst braking, a driver would have to use heel and toe, but the blip would be whilst the car was in N, as you explained.

This video shows double de-clutching whilst braking using heel and toe from 0.15.

http://www.youtube.com/watch?v=muxVLOaw2ik



rustytools

Original Poster:

9 posts

14 months

[news] 
Friday 13th July 2012 quote quote all
Cheers everyone.

I think I get it now... So in modern cars with stronger/better designed synchros than say 20+ years ago you actually don't need to double de clutch, in theory you could just blip throttle in neutral with the clutch pedal down (similar to heel toe)?

ohtari

392 posts

13 months

[news] 
Friday 13th July 2012 quote quote all
rustytools said:
Cheers everyone.

I think I get it now... So in modern cars with stronger/better designed synchros than say 20+ years ago you actually don't need to double de clutch, in theory you could just blip throttle in neutral with the clutch pedal down (similar to heel toe)?
It doesn't make a difference what gear you're in if the clutch is in. So there's no need to stop moving the stick at neutral to blip the throttle, a smooth movement from one to another whilst bliping the throttle will produce the same effect.

I can't be bothered with heel-toeing TBH, but I do double-de-clutch most of the time.

ChevronB19

354 posts

32 months

[news] 
Friday 13th July 2012 quote quote all
ohtari said:
It doesn't make a difference what gear you're in if the clutch is in. So there's no need to stop moving the stick at neutral to blip the throttle, a smooth movement from one to another whilst bliping the throttle will produce the same effect.

I can't be bothered with heel-toeing TBH, but I do double-de-clutch most of the time.
Why? It's only necessary in a car without synchromesh? Heel & toe works to minimise the effect of engine braking, and double declutching is several moves more than heel & toe.

derektrimblitz

117 posts

30 months

[news] 
Friday 13th July 2012 quote quote all
I often left foot brake when I double de clutch to help my toe n heel speed. If you don't use your left foot to brake and match engine to transmission coagulation then the back wheels can oppose weight transfer decreasing corner exit speed.

This mandarin liqueur really clarifies driving technique smile

wst

1,065 posts

30 months

[news] 
Friday 13th July 2012 quote quote all
derektrimblitz said:
transmission coagulation
We don't need none of this slushbox talk here.

derektrimblitz

117 posts

30 months

[news] 
Saturday 14th July 2012 quote quote all
We don't need this fascist groove thang

ohtari

392 posts

13 months

[news] 
Saturday 14th July 2012 quote quote all
ChevronB19 said:
Why? It's only necessary in a car without synchromesh? Heel & toe works to minimise the effect of engine braking, and double declutching is several moves more than heel & toe.
Size 11 'oofs m'lord. Simply not enough room to do it (comfortably). And whilst a double de clutch requires more steps, I've got it practiced to a point where the difference in speed is negligible. It is a handy technique to master, some of the older tractors on the farm have crash gearboxes. Also, I'm not sure of the sensibility of trying to mash three peddles at once whilst on the road. If you need to re-balance the car on turn in, you're probably going too fast. The peddle box on most cars pretty much prevents heel toe anyway, with the brake peddle set far higher than the throttle.

Besides, where's your mechanical sympathy? The engine speed sharply rising as you release the clutch peddle can never be a good thing.

pthelazyjourno

1,253 posts

38 months

[news] 
Saturday 14th July 2012 quote quote all
ohtari said:
Size 11 'oofs m'lord. Simply not enough room to do it (comfortably). And whilst a double de clutch requires more steps, I've got it practiced to a point where the difference in speed is negligible. It is a handy technique to master, some of the older tractors on the farm have crash gearboxes. Also, I'm not sure of the sensibility of trying to mash three peddles at once whilst on the road. If you need to re-balance the car on turn in, you're probably going too fast. The peddle box on most cars pretty much prevents heel toe anyway, with the brake peddle set far higher than the throttle.

Besides, where's your mechanical sympathy? The engine speed sharply rising as you release the clutch peddle can never be a good thing.
The engine speed won't be rising sharply though - he's just blipped the throttle so it will more likely be dropping when he comes off the clutch?

Still don't understand why you bother with all the faff for regular cars (outside of tractors) - we've had cars with 150k miles+ and never, ever had any gearbox issues.

ohtari

392 posts

13 months

[news] 
Saturday 14th July 2012 quote quote all
pthelazyjourno said:
The engine speed won't be rising sharply though - he's just blipped the throttle so it will more likely be dropping when he comes off the clutch?

Still don't understand why you bother with all the faff for regular cars (outside of tractors) - we've had cars with 150k miles+ and never, ever had any gearbox issues.
Ahh, goofed on the engine revs part. T'was the gearbox input I was thinking of. It does make for a smoother shift though.

As for why I bother, no idea. I'm a sucker for a smooth drive. Unless I'm out for a hoon, then I don't give two sts. Ironic really driving

shirt

14,301 posts

70 months

[news] 
Saturday 14th July 2012 quote quote all
i started learning to h&t when i bought my track car. i must admit not every downchange has been smooth [did a lovvvverly donut snatching too low a gear way too harsh!]. practising on the road is hard given the pedal travel and gear ratios on the wrongler!

thing for me is that all the vids on youtube show the driver using the toe for the brake, heel to blip. is it just me but my feet don't work this way, feels much more natural to use my heel to brake and toe to blip.

is there any reason that i am wrong? control seems fine, my foot just won't pivot far enough the other way to make it feel 'right'

CapriV6S

421 posts

11 months

[news] 
Saturday 14th July 2012 quote quote all
Just drive.

MagicalTrevor

4,810 posts

98 months

[news] 
Saturday 14th July 2012 quote quote all
IMHO double declutch isn't required nowadays because synchromesh.

I learnt how to heal and toe by first rev matching on downshifts. Drive along a straight, quiet road and slowly do the following actions (at first) do:
  • in 3rd gear (2nd to 1st is more difficult) set a constant speed at lowest revs (note the revs)
  • change normally into 2nd (now note the difference in revs at the same speed)
  • change back to 3rd
  • dip the clutch
  • add more revs to the number you know is right for 2nd gear
  • lift the clutch and it should smoothly change gear without lurching or mechanical strain on the car
(this was my technique btw, not saying it's the best)

Practice this until you can do it faster and without thinking about it. Don't bother trying to do it approaching a bend, you'll rush yourself and get confused. Next, see if you can do two gears smile

So, now you know what you're trying to achieve with heel and toe. You'll get a feel for how much you need to rev when changing 1 gear and this will be natural. Now you just need to learn the 'brake and accelerate' technique to achieve a heel and toe.
Note that some modern cars won't allow you to do this and some cars are perfectly setup for it

kambites

32,864 posts

90 months

[news] 
Saturday 14th July 2012 quote quote all
The principle of double de-clutching and of heal and toeing are rather different.

The idea of double de-clutching is to make sure that the two shafts in the gearbox are turning at the right speeds for the cogs to mesh properly (necessary in the days before the syncromesh, not so useful these days, although it still feels nicer when you engage the gear).

The idea behind heal and toeing is to match the engine speed to that of the rear wheels so you don't end up using the momentum of the car drag the engine up to speed (which can result in locking the drive wheels up and upsetting the balance of the car).

You can, of course, do both, but the heal-and-toe technique you describe is not compatible with double de-clutching. I tend to do both just because I enjoy the feeling of getting it right. smile

Edited by kambites on Saturday 14th July 09:16

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