Pedal techniques

[jw2015]

I'll be taking a driver training course on a track soon in my boxster and I'm expecting this to at least mention things like 'heel and toe'. In anticipation I've tried to find out exactly what this might entail but it's obvious that many people are only guessing about it and advice is mixed about exactly where your heel and toes go, not to mention why you might be doing it in the first place. I've gathered that the technique is for matching revs to road speed while braking and changing down, to avoid engine braking that might upset the handling when you lift off the clutch. Since I'll probably never be anywhere close to the limits of my car on the road, I doubt I really need to get to grips with this but now I'm curious about it.
First of all, have I got the right idea about why it might be required and secondly, and this may seem like a very stupid question, where does your heel and toe go? On other forums people seem to suggest that the ball of the foot is on the brake and you somehow manage to get the side of your heel to blip the accelerator. However when sitting in the boxster while parked I find that this feels particularly awkward (perhaps due to a bad lower back), but if I plant the lower part of my shoe on the brake I can much more easily swivel my foot and toe the upper part of the accelerator. So at the risk of seeming like a complete idiot, what's the recommended position?

What other techiques do people use and why; left foot braking for example, what's that all about?

 

[Rodney Naghar]

Good post, always wanted to know the correct technique for heel 'n toeing..I also tried it with the toe on the brake and heel on the accelerator...so hard especially as its hinged at the floor you can't get any leverage unless your foot is fully horizontal?[8|]

 

[Michael Downing]

I find it easiest to place my right foot on the brake pedal in an offset manner, so that it can be tilted to press the accelerator. Thus, the left edge of my foot is braking and the right edge is revving. The tilt angle controls the relative balance between the two. I've no idea if this is recommended, but it works for me.

I find it very useful on the road; there is a section of my route home which has a steep downhill NSL section, followed by a right hairpin and then a hump-back bridge. You need second for the hairpin, you don't really want to interrupt the braking on the downhill, you can't take second early because it will howl, and you can't change in the bend because it's all just too busy. Heel & toe makes it all nice & smooth.

 

[Mark_Bennett]

"heel & toe" is a misnomer. It is usually (as above) the left hand side of the ball of the right foot braking, and you then "rock" the foot over to blip the throttle with the right hand side of the foot, whilst still braking with the left hand side.

Easier done than said(!).

There were a couple of posts about this recently. A search might drag up a better description[]

 

[thboxster]

Previous correct posts about how (above). Also depending on size of foot and pedal setup, when I raced a Peugot 306 GTI the brake and accellerator where not close enough together. So, I had to swivel my foot anti-clockwise by about 45 degrees to be able to hit the gas pedal effectively.

Why? well your correct in your assumptions. If your under heavy breaking with your wheels on the verge of locking and you change down a gear without h&t then you'll get additional breaking from the engine which will unbalance your finely balanced situation. By h&t you raise the revs high enough to change down without any additional impact.

I normally use it if i'm "in a hurry".

 

[jw2015]

I did always assume that each edge of the foot on each pedal was the way it would be done but someone on another forum made the point that you might be compromising your braking without the full weight of your foot on the pedal, particularly with the lack of servo assistance on Porsche brakes. You might even be running the risk of your foot slipping off the brake pedal completely. I've narrow feet so I reckon this would be likely to happen to me.
I'm beginning to think there is no absolute right way to do it and people do what they're comfortable with, but before I get into any bad habits, I'd like to know what the recommended approach is, if such a thing exists.

 

[thboxster]

If I recall correctly, the term originated because (many years ago), the brake pedal was on the right and the gas pedal in the middle so you would brake with your heel and blip the throttle with your toe. Things changed though and the old name continued.

Mostly the rocking action is used today, unless your in some odd French car and is taught in driving schools and the like.

 

[Rodney Naghar]

If you're narrow footed and worried about things going badly wrong, why not brake less and let the engine braking (with no h&t) take over the slack [8|]

(Although it would probably takes a lot more experience to correctly guage the level of engine braking you'll get though)

 

[jw2015]

ORIGINAL: Rodney Naghar

If you're narrow footed and worried about things going badly wrong, why not brake less and let the engine braking (with no h&t) take over the slack [8|]

I have tended to use engine braking as part of a heavy braking manouvre but one of the reasons I'm interested in H&T is it's a lot better for the clutch, and probably smoother in general.

 

[Michael Downing]

Surely best to let the clutch out with H&T and then get off the gas to get the engine braking?

 

[Geoff_Fields]

Jason Plato demonstrated the technique to a Harrier pilot on Fith Gear last week. Try and catch a repeat showing or cadge a recording if someone's got it. It is how Mark and Michael are describing it as near as it makes no difference.

 

[channella]

I'd suggest going back to basics first. Separate braking and the gear change - brake to get the speed down, then take the correct gear for the bend and to give maximum acceleration round and out. Use a sustained rev change or a blip as you move through the gate to match revs to road speed for the gear to keep it smooth. If the instructor then teaches you how to use H&T it will be with the basic skill in the bag, and you will know better what you want to achieve perhaps. H&T allows you to compress the distance and therefore the time taken, but keeping the car smooth, balanced and under power will feel better and be more effective at making progress.

Not really sure I'd be worrying about engine braking - brakes are several times more powerful than the engine and its cheaper to replace pads than the clutch.

 

[Guest]

Engine braking is using the compression of the engine to slow the car. This means drive along and lift off the accelerator, the car will slow. The higher the revs the more the car will try to slow.
To increase the braking effect, you can change down. When you change to the lower gear, you will need to increase the revs.
You can do this by pressing the throttle to match the revs, then letting up the clutch, followed by lifting off the accelerator again to recume braking, or just putting it in gear and letting up the clutch.
The first is smoother, kinder on the car since you wear the clutch less, and unballances the car less since there is no sudden change in braking force.
Allowing the clutch to bring the engine speed up will slow the car, but it inefficient (since the brakes are better for sudden changes) and will cost more (since brakes are cheaper than clutches).

If you are approaching a corner at roughly the right speed, you may want to drop it a gear to give better control and to give better acceleration out. You can do this just by dropping a gear to and matching the revs. No actual braking is required.
This is easy to practice since yuou can drive at constant speed, e.g. 40, going from 2-3-4 and back down again.
If you do it a bit before the corner you can allow the engine braking effect to slow the car. By being smooth and planning ahead, you will find you don't have to brake very much at all during normal driving. Certainly it is much less than most people do.
The only thing to be aware of is that no brake lights show, so the person behind you gets no visual warning that you have changed from 60-50, for example.

If the speed into the corner is higher, you will need to slow the car more significantly.
The brakes are best for this, since it is what they are designed for.
You can change down before you brake, although this may not be possible if you want to slow a lot, without over revving the engine.
You can brake down to the correct speed, then change, since you are doing the same as before.
This is what I tend to do most of the time.

Or you can try to change down whilst you are braking.
The aim is to match the revs to the road speed at each gear change, to save the clutch and avoid unsettling the car.
As you change down you will need to blip the throttle.
As already mentioned, you can do this by braking with the ball of you foot and using the edge to press the accelerator. This take a fair amount of practice to make it smooth.
You save 0.5-1 secs, which also means you can come off the brakes later. Since you want to be at the correct speed, in the correct gear, with the car settled and power applied before you turn into the corner.
On the road, you can drive perfectly reasonably without ever having to worry about it.

You will need to be careful, because if you get used to doing this and then have to make an emergency stop, you need to be careful not to press the accelerator at the same time.
(I did this twice, once on the turbo test drive - which is embarassing and lengthens your stopping distance quite considerably).

The 996 is setup quite well to do this, although many cars are not. The pedals are either too far apart, or more often, when braking the brake pedal is much lower than the accelerator pedal, so it is impossible.

Left foot braking can be used for several reasons.
The obvious one is where you approach a corner in 3rd say at 7000 rpm, want to slow to 5000 rpm, so don't really need to change down a gear, since you will run out of headroom on the wayt out and need to change again. Since you are not going to change gear, you don't need the clutch, so you can use you left foot to brake. You can then apply the throttle immediately, saving a tenth or two. It takes some practice to judge how much to press the brake pedal, since if you press it like the clutch you will headbutt the windscreen.
It used to be used most often on turbo cars, where you wanted to keep the power on, to keep the exhaust gas pressure to keep the turbos spinning, but also slow down a little.
The other usage is for rallying to balance the car, where you are trying to control the slide and how much power is going to each axle. I doubt this will apply to normal road driving.

Next you'll be wanting to know how to use the handbrake to get round a corner.

 

[Rodney Naghar]

Excellent post (as usual)[]

 

[Michael Downing]

ORIGINAL: Stuart Martin
Next you'll be wanting to know how to use the handbrake to get round a corner.

If you're going to explain it that well again, then yes please! []

 

[Mark_Bennett]

(With apologies to the original poster...)

Is this the right time to mention double-declutching? [][]

 

[channella]

Go on Mark, mention double-declutching...

 

[juliany27]

When changing down a gear, if your get the revs right it is possible to change gear without using the clutch and without a terrible crunching sound as yopu engage the gear.

I have mastered that technique in another car - I was taught by my father who was, in turn, taught whilst serving in the Army during the War when spare clutches were difficult to find.

However, it takes a lot of practice unless you have a musical ear and can judge the revs very accurately. And if you get it wrong too frequently, the effect sounds horrible and the cost can be huge!!

 

[Guest]

Whilst rally drivers used to avoid using the clutch, I am not sure I would want to.
I can't afford to replace the gearbox after every couple of stages, e.g. driving to work for a few days.
To do it accurately at full speed and with a lot of power applied, is pretty tricky and stands a very good chance of chipping gear teeth. (Edit: sorry you can't chip the gears, since they are always engaged, hence the synchromesh name, what you will damage is the gear selector splines, I believe. Although I have looked at it several times, I can't quite visualise exactly how the drive is transmitted through the different gear ratios. I need to take one apart, but I can't be bothered.)
I'm not convinced it is all the that useful for normal driving unless your clutch cable snaps. Although how do you get it into first to start moving?

With a modern synchromesh gearbox, I can't see the point of doube declutching.
I know one or two of the independent driving instructors mention it, but aside from some nostaligia for an older driving style, I can't see the advantage of it. I can't see how it can reduce wear and tear.
Since it takes longer to change, then given that the revs on any proper sports car die pretty quickly as soon as you lift off the accelerator, it makes it harder to match the engine revs to the road speed.

As for the handbrake, on the 996 (not sure about all the other models) the handbrake operates on drum brakes inside the rear hubs, not on the disc brakes you can see. This is since a handbrake cannot easily apply enough pressure using a cable to the discs (the hydraulics with the vacuum assist apply a lot of force). It has the advantage also of allowing you to stop when the discs are hot, but not hold it on the foot brake which bakes the pads onto the discs.
Whilst the brake holds you well when stationary, try using it when you are moving.
Get up to 10mph and pull on the handbrake - it does almost nothing, at least on the 996. I was quite surprised.
Due to this, I am not sure you can really use it when moving.

The reason for using it, is when you have a tight corner where you would run out of lock, e.g. a tight hairpin on a mountain road, or an acute road juction, you can get round it more easily by sliding the rear out.
In order to get the rear sliding, you need to brake the rear more than the front.
The handbrake only brakes the rear wheels, so is useful for this.
The easiest thing is to stop the rear wheels turning, although you only really need to slow them enough to brake traction. (Which is why you could in theory do it by mismatching the revs and letting the clutch up, since this will give a sudden braking effect on the rear wheels).
You need to approach the corner faster than you would need to, to drive around it, then turn the wheel, pull the handbrake.
If you are in a rear wheel drive car, you will stop the engine turning and stall the car (if you can apply enough force with the handbrake).
In a front wheel drive car this is not an issue, so it is easier on fwd car.
You now have the back sliding, you need to judge, when to let the handbrake off, when to let the clutch up, matching the revs of course which may otherwise have died, whilst also steering.
You may also need to be careful of the slide you are in whilst applying power.
On tarmac it is not that easy.
On ice it is a lot easier to do.
Note that with a 911, you have chance of just spinning, since all the weight is out the back, which will pull the car round.
On the public road, I can't think of a scenario where it would really be useful, or not frowned upon. It does of course also wear the tyres unevenly.

Whilst we are on the subject, how to do a doughnut.
Buy a turbo, switch off traction control, put in first, start to just move, turn wheel over hard and press accelerator to floor. In the wet this is all you need.
With less power or a dry surface, start to move, then dip clutch, raise the revs, let up clutch briskly to start the rears spinning.
You will need a lot of room, and once the rears start to spin you need to let up on the accelerator since you do not need much power to keep them spinning.
You can keep you foot mashed down, but you will be right up against the rev limiter, which is a bit harsh on the engine and not really intended for this sort of abuse.
It is not so good for the diff. However, if you are driving Porsche GBs car, it is good fun.

Next, what is the LSD, and why does Porsche have a different locking ratio on drive and overrun....

 

[channella]

My own view of D-D is that with modern gearboxes it's not really necessary. A nice technique to have in our tool-box though. Having said that, I occasionally use it on a down-shift, becuase it forces more thought about what I am doing and can help with smoothness. I don't see the point with and up-shift. I have been shown that a slight lift off the gas just before disengaging the clutch helps settle the car and with smoothness, but the trick is to adjust the reves to the right level before re-engaging the clutch.

One other thing I've come across recently is to "hint" at the steering input. That is to put a smaller amount of steering in sooner, before applying the final input you need allowing the tyres to develop a slip angle, then use power to push the car round. It sounds like I've described two steering inputs, but it should really be one smooth one started a little earlier.