Left-foot braking

[gangajas]

Interesting vid:

http://www.autocar.co.uk/VideosWallpapers/Video.aspx?AR=224464&Mode=B

I've tried left-foot braking, but when I drive 'fast' (relatively) I feel safer with right-foot braking, because I haven't really mastered the technique yet. Same with heel&toeing.

[ViperASR]

I left foot brake in the mini-van just because I'm used to always using my left foot for something and it reminds me of driving a cart as it is an automatic.

When I'm driving quickly in the 944 I heel&toe. The pedals are set up beyond perfectly for it, making it really easy to learn.

Intersting video about the Torsion front diff though

[ARMAN]

dont really understand how much it will add you in control other than you have your left foot ready to break rightaway... just higher fuel consumption and brake disks wearoff?
maybe in focus rs with its cool differential it can make a difference but what it does for normal fwd or rwd?

btw brilliant idea from Autocar to make such vids, i always loved reading Chris Harris's articles in czech Autocar in the pre-JW age :) LOL

thanx for linky Gangajas :wink:

[graywolf624]

Completely useless technique on a track or road despite what he says. The only reason to left foot brake is to unsettle the car for things like slides. Its not the best way to get around a corner. It might help you if you've already screwed up to correct understeer or oversteer, but its not what you should be doing.
Go karts.. good for keeping the revs up..
Rally cars, good for forcing the proper amount of rotation.
But other wise not worth it.

Hell my Iroc had a torsen differential. Left foot breaking does nothing for it. Hes essentially trying to argue that by braking while accelerating he keeps the cars weight from shifting rearward. The problem with that arguement is that you can do the same damn thing by moderating your gas correctly rather then hitting it hard.

[TopGearNL]

Reminds me of the Walther Rohrl vid :)

Anyway pretty interesting, would like to master that technique one day!

[coombsie66]

Completely useless technique on a track or road despite what he says. The only reason to left foot brake is to unsettle the car for things like slides. Its not the best way to get around a corner. It might help you if you've already screwed up to correct understeer or oversteer, but its not what you should be doing.
Go karts.. good for keeping the revs up..
Rally cars, good for forcing the proper amount of rotation.
But other wise not worth it.

Hell my Iroc had a torsen differential. Left foot breaking does nothing for it. Hes essentially trying to argue that by braking while accelerating he keeps the cars weight from shifting rearward. The problem with that arguement is that you can do the same damn thing by moderating your gas correctly rather then hitting it hard.

He is not trying to argue that braking whilst accelerating keeps the weight transfer forward at all, that is just stupid as it means that the car is not accelerating if you are increasing the weight transfer to the front of the car.
What he is saying, which is actually correct is all to do with the quaife ATB differential in the front of the focus RS, i know about this as we fitted one to the rear of our formula student car at university and spent quite a bit of time altering suspension set ups and driving techniques to get the best out of it traction wise.
The torsen or quaife ATB are essentially the same in function (not neccesarily design). Both are not limited slip, therefore they do not work at 100% slip, as chris harris stated. The reason for this is in the design, in a limited slip diff you have a series of clutch plates (or viscous plates, or cones etc depends on design) that try to equalise the speeds of the two outputs of the diff when there is a certain amount of speed differential between the two outputs. The ATB or torsen does not have these plates, it depends upon the friction force on the end of the planetary gears inside it which are thrown in a particular direction depending on the torque varience across the diff and its outputs. Its a bloody difficult thing to understand when you have the pieces in your hands let alone to explain!
Anyway, the only time the ATB doesnt bias the torque across the diff is when there is too much slip on the inside wheel (we found this as we were picking up the inside rear on the apex and exit of corners) when this happens, the only thing limiting the slip of the inside wheel are a few sprung washers in the middle of the diff, and they do very very little and are not going to hold the torque produced by the engine which is soley trying to spin the inside airborne wheel!! It just acts like an open diff.
So (i eventually get onto the left foot thing!) by left foot braking on the apex and exit of the corner, you are applying a braking torque to the inside wheel, this means that there is less slip on that inside wheel and therefore the diff is sending more torque to the outside front wheel (in the Rs's case) meaning better acceleration out of the corner. This is mostly the case on uphill exit, slippy, gravelly, tight corners, where your typical ope diff'd FWD car would be sat there spinning the inside front for half an hour before you get anywhere!!
You are effectively using the brakes to act as a clutch pack to lock the differential when the slip of the inside wheel becomes too much, and you keep the accelerator buried so that you are overcoming the braking torque you are applying with the extra engine torque.

Its all about transfering torque to the wheel that has the most weight on it, which the torsen differential fails to do beyond a certain slip point. Anyone remember the video of the audi quattro vs the bmw X drive trying to drive the car off of some rollers with the front wheels on the ground and the rears free to spin on the rollers. The audi which had a torsen centre differential failed to get off for the same reason, too much slip across the diff, if the driver applied the brakes to the rear wheels then it would send torque to the fronts and drag the car off the rollers (as they eventually did). :) 8)

[Vansquish]

Completely useless technique on a track or road despite what he says. The only reason to left foot brake is to unsettle the car for things like slides. Its not the best way to get around a corner. It might help you if you've already screwed up to correct understeer or oversteer, but its not what you should be doing.
Go karts.. good for keeping the revs up..
Rally cars, good for forcing the proper amount of rotation.
But other wise not worth it.

Hell my Iroc had a torsen differential. Left foot breaking does nothing for it. Hes essentially trying to argue that by braking while accelerating he keeps the cars weight from shifting rearward. The problem with that arguement is that you can do the same damn thing by moderating your gas correctly rather then hitting it hard.

Edit: Coombsie's got it, I just rehashed it.

On the contrary, he's not suggesting that left-foot braking keeps the weight shifted to the front of the car, he's suggesting that the way that the differential works in the Focus RS (Renaultsport Megane F1 etc...) is that it apportions torque rather than limiting slippage. Therefore, when accelerating in a sharp turn, it can be used to the advantage of acceleration by slowing the inside wheel a bit and allowing the torque to transfer to the outside wheel and provide more drive through the corner, countering understeer. This way that he's describing the technique, it ONLY applies to FWD and AWD cars. A rear-wheel drive car like the IROC Camaro would not achieve the same handling benefit by left-foot braking during acceleration. The only time it would be useful is entering a corner and making the transition from braking to accelerating out of the corner a bit smoother.

[andreadebi]

Reminds me of the Walther Rohrl vid :)

Anyway pretty interesting, would like to master that technique one day!

which video please?

[pitfield]

I feel educated, thank-you for that. This is what JWis all about.
I often blip the throttle on downshifts in my MINI while braking with my right foot, is this heel and toeing?

[pitfield]

Oh great, it's piece of cake in the MINI, tried it in dad's Alfa 156 and the offset pedals make it difficult. Learnt to do this in the old C4S ex demo car at Porsche, not for the performance side of things but just with the sports-exhaust it sounded bloody brilliant.

[Stoopie]

With my previous job I had to drive a forklift truck pretty much, and then I used the brake with left foot too, it's just way easier IMO :)

[dutchmasterflex]

Heal and toe shifting is easy.. but when you throw in some left-foot breaking a long with it you need Walter Rohrl like powers.

I try to practice left foot breaking in my car just so I can have a better feel for the pedel with my left foot. Driving the shifter kart I don't really notice how bad my braking is since I'm using my left foot, but it definitely has an effect on my lap times.

[graywolf624]

With fwd cars, the left foot braking does improve the times, at least when driving on gravel or snow. Rally drivers generally use the left foot braking to "tie" the car in the corners. SKilled use of the left foot keeps the car from understeering and oversteering, improving the traction of both front and rear wheels. I'm not sure how much does it help of asphalt with good traction. And ofcourse it is very rough to the brakes.
As per above I certainly believe it could help you to unsettle the car on a rally course. A bit of a different beast then track driving.

I stand corrected on the reason. It only applies to fwd cars, which don't belong on a race track. So I defend my statement that its useless on a race track. :P

[TopGearNL]

Reminds me of the Walther Rohrl vid :)

Anyway pretty interesting, would like to master that technique one day!

which video please?

walter röhrl rally audi S1 - YouTube 8)

[gangajas]

It only applies to fwd cars, which don't belong on a race track.

What?

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[graywolf624]

Don't compete with rwd cars except when the rwd cars are weighted down in spec classes.
FWD= inferior to rwd for the race track. Easily proveable with any simple physics knowledge. Ask the front tires to do everything and they give out alot quicker.

[TopGearNL]

^^What about WTCC? ( non Bmw then)! :shock:

[graywolf624]

WTCC is a great example of using weight to make the fwd competitive. I still think its a case of spec making them useful. Id never build a fwd race car. Just a waste imho. I don't tend to care for the racing series that use fwd either.

FYI: WTCC allows a lower overall weight requirement for fwd cars over that of rwd and awd.

[TopGearNL]

^^ Ah I see..

Well you do have a point since the Bimmers always seem to win..

[gangajas]

WTCC is a great example of using weight to make the fwd competitive. I still think its a case of spec making them useful. Id never build a fwd race car. Just a waste imho. I don't tend to care for the racing series that use fwd either.

Well, that doesn't mean that there haven't been great FWD racing cars:

http://en.wikipedia.org/wiki/Alfa_Romeo_155#155_in_motorsport

The Xsara Kit Car that won tarmac rallies beating all the WRC cars:

1999 Tour de Corse:

http://en.wikipedia.org/wiki/Tour_de_Corse

1999 Rally Catalunya:

http://en.wikipedia.org/wiki/Rally_Catalunya

etc, etc.

[graywolf624]

The Xsara Kit Car that won tarmac rallies beating all the WRC cars:
A rally is not a race track. A rally is a rally. Even with tarmac theres a completely different style of driving and setup required.


http://en.wikipedia.org/wiki/Alfa_Romeo_155#155_in_motorsport

Weight comment again.

[gangajas]

FYI: WTCC allows a lower overall weight requirement for fwd cars over that of rwd and awd.

WTCC doesn't allow AWD. Anyway:

The minimum weight of the car, including the driver and his full
equipment, is :
- 1110 kg for a front-wheel drive car the gearbox of which is
original and homologated in Group N,
- 1140 kg for a front-wheel drive car the gearbox of which is
homologated in VK Super 2000,
- 1140 kg for a rear-wheel drive car the gearbox of which is original
and homologated in Group N,
- 1170 kg for a rear-wheel drive car the gearbox of which is
homologated in VK Super 2000.

As all the FWD use sequential gearboxes and the BMWs (except for Zanardi's car) use manual gearboxes, the minimum weight is the same for all the cars.

[graywolf624]

As all the FWD use sequential gearboxes and the BMWs (except for Zanardi's car) use manual gearboxes, the minimum weight is the same for all the cars.
Uhh..
Thats the minimum weight.. But they add additional weight for the cars that win. The bmws are no longer allowed at the minimum. Either way your handicapping the cars in favor of fwd, and the results are still rwd wins.

[TopGearNL]

The Alfa Romeo 155 DTM V6 was AWD :wink:

[graywolf624]

he Alfa Romeo 155 DTM V6 was AWD
Your not helping his position lol.

[gangajas]

The Alfa Romeo 155 DTM V6 was AWD :wink:

Yes, and the nose-heavy, understeery Audi A4s that dominated Super Touring.

graywolf624 said that "It only applies to fwd cars, which don't belong on a race track"

Maybe some RWD or AWD cars are a little bit faster than FWD, and Priaulx is a master at Macao that's why he always win the Championship in the last date, but that statement graywolf posted it's too radical and not true.

[TopGearNL]

^^ I said it because you said this

Well, that doesn't mean that there haven't been great FWD racing cars:

http://en.wikipedia.org/wiki/Alfa_Romeo_155#155_in_motorsport

[TopGearNL]

he Alfa Romeo 155 DTM V6 was AWD
Your not helping his position lol.

It was meant in your favor :wink:

[gangajas]

Enjoy the power of a proper tuned Civic :D

2L Honda V-tec Challenge - YouTube

FF rulez! :P

[graywolf624]

but it's true they're FWD just because it's the cheapest you can get. For sure we would love to drive a Clio V6 Trophy
Exactly.

Maybe some RWD or AWD cars are a little bit faster than FWD, and Priaulx is a master at Macao that's why he always win the Championship in the last date, but that statement graywolf posted it's too radical and not true.
All other things equal, the rwd will always be better then fwd for road racing.

[TopGearNL]

^^ :lol:

[ViperASR]

I feel educated, thank-you for that. This is what JWis all about.
I often blip the throttle on downshifts in my MINI while braking with my right foot, is this heel and toeing?

Yes it is.
http://en.wikipedia.org/wiki/Heel-and-toe

Actually, heel and toeing is when you use your right foot to brake and blip the thorottle while changing down gears at the same time. Braking with your left foot is called left foot braking :lol: .

left foot braking is generally associated with automatics and go carts.

[number77]

left foot braking is for RWD cars to (on paved racetracks). I know an SCCA driver that consistently wins that does it. But you have to be really really good to do it. I mean...really good.

[pitfield]

It's a piece of cake dude. If you want, I'll show you. I'm not trying to prove that my journey to work is 0.001sec faster because of it but it does make down shifts much smoother which must be a little more sympathetic to the machinery.

And besides, it sounds badass.

[andreadebi]

Reminds me of the Walther Rohrl vid :)

Anyway pretty interesting, would like to master that technique one day!

which video please?

walter röhrl rally audi S1 - YouTube 8)


grazie!

[saadie]

heel and toe has got nothing to do with left foot braking :lol:

heel and toe is essential when you are driving fast in a rear wheel drive car ... braking with the toe and giving the throttle a blip with the heel keeps the revs up so when you drop the clutch the rear dosnt lock up ( usually happens in racing cars ) .... if the rear locks up you'd be pointing where you've come from ;) ... heel and toe also helps in braking .. there is a little power going to the wheels and your toe is on the brake so it acts a little like abs .... the wheels dont lock up ...

i left foor brake all the time .... there is this really nice mountaneous road near my place when comming down youre mostly in 2nd gear .. sometimes in 3rd ... when ever i am in 2nd im left foot braking its damn good fun 8)

[pitfield]

I think when they say heel and toe they refer to when the accelerator was on the other side. Nowadays you use the right foot placed between both throttle and brake and flip the right sideof your foot down to blip the throttle, haven't tried to left foot brake, a Porsche driving instuctor showedme once on track but I didn't really get it, next thing to learn.

It has be said though, I'm a heel and toe fucking MASTER

[saadie]

Nowadays you use the right foot placed between both throttle and brake and flip the right sideof your foot down to blip the throttle


you are right ..... the distance between the acclerator and the brake has been shortened over the years ...

so now your foot is in the middle and you use the left side to brake and the right side to blip the throttle .. just like you said ... ... but yeh .. its still called heel and toe ...


It has be said though, I'm a heel and toe fucking MASTER

youre fucking 75 :lol: you need a lot growning up to do :lol: :mrgreen:

[saadie]

true ... heel and toe also depends on the throw of the brake and accletator .. if the acclerator moves alot more then the brake then you realy have to keep your foor horizontal ;) ...

[pitfield]

Growing up???

For who?

[saadie]

:lol:

it was a joke on your age

Age: 75
Joined: 29 Jun 2005
Posts: 267
Location: Mayfair/Brighton

[saadie]

get you peddle fixed :)

[dutchmasterflex]

Have any of you experienced difficulties in heel&toeing, because of the lag in the gas pedal? You can't just flip it, because revs don't go up with a flip, but you have to keep it depresses for a while. It sucks even to practise with such system.

I know what you mean.. I taught myself on a 1.5L 4 banger, which has decent throttle response.. but when I hopped into a 6speed Benz C240, the V6 didn't rev as quick when tapping on the throttle.

You have to really make sure you give the gas pedal a nice hard blip.

[pitfield]

In the MINI Cooper it's doddle, in the supercharged cooper S it's fantastic because you get burlbles on the over run, and the turbo cooper S lags a little but you can use it as an excuse to keep the engine on the boil.

Left foot braking is also good for keeping Turbo cars on boost, especailly old super laggy ones.

A merc V6 is just too lazy for that sort of work.

[dutchmasterflex]

Anyone ever force an automatic to rev match? I know it can't be good for the reliability of the transmission, but sometimes when in a hurry I downshift into 2nd in an auto and if I blip the throttle it will downshift faster and smoother.

[pitfield]

Autos piss me off so much that when I drive them I hope to reduce their lifespan, there's nothing quite like getting one of the bimmers, turn off DTC, hold the brake just ever so lightly and bury the throttle, so satisfying. Especially in a 650

[graywolf624]

I just want to correct that is not used to unsettle the car in rallying. but I just want to correct that is not used to unsettle the car in rallying. It is used to settle the car and increase the traction of the rear tires and keep the car in balance.
I agree, Im being rather basic though as my rally knowledge is limited and always will be.

[SPEEDKILLAR]

Buy an automatic :roll: