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Heel and Toe.


Anthony Micallef

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I'm godsmacked at how few times "smoothness" has come up in this thread.

 

The whole point of H&T is smoothness on downchanges so as not to upset the balance of the car. If your pedals are set up correctly it's a piece of cake in the 7. A variation on the theme is also usful for hillstarts if you drive a "where's the handbrake, oh there it is under the dash" type seven. Downchange timing is a matter of preference and prevailing conditions.

 

If LFB works for you, great, but in my experience it upsets the car more than settles it (clumsy left leg I guess). I thought it was originally started by the turbo car (Audi?) rally drivers to keep the turbos up to speed to avoid lag on applying (full) throttle? There is also some advantage in saving time getting your right foot from the brake to throttle pedal and vice versa but personally I lose more time cocking up the braking!! You have to be b****y good to make it work, and I ain't! Gotta get the smoothness of everything else licked first...

 

NN blush.gif

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For the full experience mix H&T with constant throttle double declutching. The costant throttle bit works like this. If you don't change the position of the throttle when you press the clutch, the revs will rise. By timing the clutch/gear movements properly you can achieve a smooth change.

Now try keeping the throttle position unchanged while braking with the right foot, the left one is busy with the clutch).

 

Dave H

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Paul,

 

The point I am making is that most synchro boxes including the 5 and 6 speed units in Caterhams will not permit a smooth downchange if you wish to engage the lower gear at anything like max rpm. the gear will just baulk, and if you have a five speed, 1 time in every 10 this happens you will break a syncho ring or blocker bar.

 

Coming down the box at the end of lavant for the woodcote double apex is agood example. I used to run an 8500rpm redline and could not engage 4th or 3rd at above 6000rpm for the drive through woodcote and would often screw up the lap through inability to get the gear. This is probably seq box is really worth its weight in gold, anywhere where you want to lift late, brake late and be in the right gear for the corner.

 

I guess turning into lap 2 at the end of the straight at Curborough will be a similar situ.

 

 

 

Fat Arn

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I don't have 'competitive' data logs for Curborough. A relatively desultory 55s two lap run in testing shows a stop from 100mph to 30mph for the start of the second lap. This appears to take almost 4 seconds, although I've backed off the brake pedal slightly by about 75mph, the two gearshifts occur between 67 and 55 and the minimum speed in the hairpin is 32. My engine will take full throttle at 3500rpm and I reach 80mph/8400rpm before backing off for the Molehill. The lateral g stays below -0.5 from the entry to the hairpin all the way up to the apex of the Molehill (peaking at -1.3). This is what it feels like, but it isn't what the track looks like. It's the reason why a lower gear won't help, any more power would cause wheelspin or other unbalancing activity.

 

I'd better stop dumping irrelvant data.....

 

Anyway you will be reaching roughly similar top speeds, but will probably have to brake to a slightly lower minimum speed.

 

If I get decent traces from next week's test perhaps I'll stick images up on the web somewhere....

 

Anyway the point is that the maximum revs you need while braking are those you want to leave the corner at, in the case of the Curborough braking that's a mere 3500.

 

Perhaps someone could make audio recordings of the Curborough runs that we could review for HnT quality?

 

Paul

 

 

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No Nuts - agree! I asked if smooth=quick.

I get great satisfaction from smooth gear changes, where you cannot feel the slightest change in motion (ie: jerking or lurching), apart from smooth deceleration or acceleration. I am not talking about 9/10ths lap times here, just fast cross-country driving.

 

Edited by - angus&tessa on 12 Apr 2002 08:25:33

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Heel and toeing is MUCH easier on a Motorbikesmile.gif

 

Surely if LFB in a RWD car the act of trying to compress the car will promote loss of traction at both endsquestion.gif Giving rise to earlier wheelspin at the rear and more pronounced understeer at the front.

 

I have found LFB handy to handbrake turn a FWD car once the hanbrake cable's snapped tho.

 

Mark

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  • 3 months later...

Having read this contentious thread with much interest I was discussing it with a Jag-Driver friend of mine last night. He pointed out quite rightly that rally cars are "clutchless" and so have some kind of fluid linkage between gearbox and wheels, this means that you can rev the engine, have your foot on the break and not change the length of your car. This is great for maintaining engine speed so you can accelerate away from the corner whilst breaking into it. Needless to say, unless you have an automatic 7 (does such a thing exist?) left foot braking will not give you the advantages above!

 

Kermit the frog (when you see Y68 YBP you'll understand)

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Article unashamedly copied from an excellent web site - www.drivingtechniques.co.uk (it covers heel & toe as well)

 

--------------------------------------------------------------------------------------------------------------------

 

Left foot braking in a rear wheel drive car is quite unusual. It's first use is to aid stability in corners, and help keep turbos spinning by holding the car at the correct speed with the brake and keeping your foot on the gas. Apart from this, it has recently been adopted by some drivers as disaster recovery.

 

If you are tanking into a corner, particularly in the wet and the car goes into massive oversteer you may wind on the opposite lock. If it has gone too far it may be possible to floor the accelerator and hit the brake with the left foot.

 

The idea is that you will keep the rear wheels turning due to the power of the engine, but will lock up the front wheels. This puts more grip to the rear wheels and less to the front, hopefully bringing the car straight.

 

This is really only a last attempt technique for recovering previously irrecoverable situations. If you were to use it as a general driving technique you will be one of the slowest drivers on the road... I mean track!

 

 

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