E. J. - 993 Alumni

I agree with DJ - especially to cure the understeer in the long sweeper corners. Just a quick dab with the left foot should be enough to tuck the front end back in. This is a delicate maneuver so be careful. It also helps in trail braking as DJ pointed out.

What I really want to comment on is that anytime a discussion about left foot braking comes up, someone says that F1 and Cart guys do it. It is totally irrelevant how they brake and shift in their million dollar racecars as compared to someone learning how to drive the cars we do. Most F1 guys do it for many reasons - the first and biggest is because they don't have a clutch pedal. The only time an f1 car uses the clutch is at the start and pit stops, therefore they use a button (usually on the steering wheel) to engage and disengage the clutch. In fact there was only one driver last year that had a clutch pedal, and guess who that was - yup, Alex Zanardi. The second reason they left foot brake is because 99% of them started racing karts when they were 4 or 5 years old and guess what pedal is missing in a kart - that’s right the clutch. In fact karts pedals are set up in a way that the brake is on the left of the steering column and the throttle is on the right. As they progress up the ladder of racecars, they start racing single seaters with sequential gearboxes that also don't require the clutch to shift gears. Then they get to CART or F1 and they still don't need to use the clutch to shift gears.

As far as NASCAR goes, I can tell you that on ovals, they all left foot brake. I rode with Greg Biffle last year in his Busch car around LMS and it was totally different how I drove my 993 around the banking at a DE. He drove full throttle (about 185) into turn 3 and did not start braking (with his left foot) until well passed the center of the turn 3 designation. It was remarkable. He told me later that they do that to give the specialized suspension a chance to settle into the turn. When I told him I had to brake my 993 from 140 to about 110 at the end of the backstretch in a straight line he laughed and said something about oval race cars compared to Road race cars...

As for NASCAR cars on road courses, they drive those beasts so differently that it is funny. Remember that the weigh 3400 lbs and have a ton of torque and only 4 gears. It is better not to upset the car with a downshift and let the torque power out of the turn. Of course they have to downshift sometimes, but the in-car foot-cam that comes to mind first is the sweepers at Sears Point. Those cars are fun to drive there. Lots of body roll and sliding. Don’t ask me how I know though.

Of course rally guys do it to help break traction from the 4wd - especially on asphalt.

As far as saloon cars go though (including supercup cars) - any car with a normal (not sequential) gearbox will not use left foot braking. Except once again in corners where you don't downshift. Then they will all do it.


Just my $.02 worth. Hope it shed some light on racecar side of this discussion.

[ 04-06-2001: Message edited by: E. J. - 95 Carrera - No. Va. ]

Steve Weiner-Rennsport Systems

Great thread,..... !

E.J. really "slobbered a bibfull" on this subject about the differences between all these cars and why some folks use LFB.

I'd add one thing that in my 935 days, we braked with the left foot to help alleviate the massive throttle lag that a 3.2 litre 700+ HP, 4-speed car has. This further had the benefit of settling the chassis all the way through the corner and allowing one to deal with the spool differential (none!) that these cars have.....

IMHO, aquiring and fine-tuning one's left foot braking skills in any turbocharged car will make you faster and exit corners much quicker, once mastered. This is however, somewhat risky to learn and is much harder on brakes!!!! Standing on the gas and using the brakes to control exit speeds is tough on rotors, pads and fluid.

--
Steve Weiner
Rennsport Systems

Anir

Thanks to everyone for the many helpful responses. I've been practicing around town, and it feels promising. As Jim suggested, I see this as more of a track technique, but worth practicing on the road - especially since I spend a lot more time there! I am saddly stuck at the "incapable and unconscious" stage on most racing techniques at present!

Keith, in the Autocar article, they specifically mentioned that a high clutch pedal in a street car can make the technique more difficult, so you're not alone.

Hey Greg, doesn't Jerry like LFB? Maybe, that's how he took you at Mid Ohio!!!

DJ and EJ, your comments highlight what really got me thinking about LFB: using it in conjunction with slight throttle-lift to curb understeer in certain corners. In my hands, the 993TT definitely has a tendency to push somewhat. I chalk this up to the AWD.

With some upcoming suspension work (Steve, you'll be hearing from me!), I hope to dial out some of the understeer, but I've been wondering about techniques such as left-foot braking being a useful adjunct.

Great posts - I appreciate the help!

addictionms

One final thought, I did a lot of my practice in a dodge ram diesel automatic, the automatic takes the need to move your foot over to the clutch ever.

Paul

I became a big fan of left foot breaking when driving my dad's '76 Sportomatic through the twisties. A light application of the brakes thorough turns not only kept the engine in the torque band, but made the standard diff act like an LSD.

On a slight tangent, the best way to get a rear wheel drive car unstuck from gravel or sand is to semi-lock the rear wheels with the parking brake. We've helped many a Maui tourist get out of "sand traps" ;^)

Paul

keith

GOOD IDEA!

I will have to try this to limit wheelspin while autocrossing (no LSD )

J richard

It seems to me that LFB is a easy way out of refining a heal and toe technique. Getting down a good double clutch/toe brake/heal throttle allows you all the control you need while your pulling G's with your left foot firmly planted.

Even with shifter karts (that duplicate the F1 paddle shift/brake layout) you will be faster if you can keep the kart balanced between braking/accelleration rather than pushing horsepower into your brake pads.

Of course I am talking about road courses where you use all the gears, not the roundy round momentum stuff...by the way I had heard of a rally technique that used the handbrake in a most unatural way...those guys will try just about anything...

patr

Hey guys.

Left Foot Braking when referred to by Pentti and when referred to by other rallyists refers NOT to:

1) just using the left foot to brake (like in karting/F1 because the pedals are there)

2) heel and toe'ing or double clutch downshifting

It refers to using the left foot to acheive effective weight transfer to the front wheels, without having to lift off the gas.

This is how 2wd front drivers can actually oversteer (like ice-racing Golfs, for example, or any 2wd front driver rally car).

In all wheel drive vehicles, left foot braking is also extreemely effective in rotating the car on turn entry without altering the line (i.e. pitching it in without understeering). On turbo cars, it allows you to maintain full boost while braking without the need for anti-lag systems, as the wastegate will not open sincve the accelerator is still mashed to the floor.

On most street vehicles, equipped with power brakes, you cannot effectively left foot brake as the vaccum assist is not present after the second or third pump of the pedal. The reason this prevents you from effective left foot braking is that the first time you push it, is it easy and a lot of travel, the second time, you get less travel and it is a lot harder, and the third time, you have no power brakes and you have to push really hard (all for the same amount of application to the discs).

In any case, if you've ever understeered in an all wheel drive or front wheel drive car and wanted to know how come those rally guys are all opposite locked, it is because they are left foot braking.

While under FULL throttle (with a slight, but ever so slight, lift of the throttle, but dont lift it when you are braking), turn in slightly and push on the brakes. You will feel and hear the engine bog under the brakes. What is happenening is that you still have rotational torque being applied at the wheels, but for this instant (right after application) all the weight is now on the front tires. The rear end is light, the front has more bite, give the wheel a quick jerk and presto, 4 wheel drifts.

If anyone is wondering, I am a 2001 C4 owner and driver for the Subaru factory rally team (I drive the new WRX turbo here in Canada).

-Pat

patr

One last thing, if you want to rotate the car, I mean you REALLY have to push on the brakes, you have to 'dump the front' as we call it (put all the weight on the front tires so they wont unstick).

-Pat

Anir

Pat,

Thank you for explaining LFB so well. I'm not exactly the voice of experience, but did feel that the technique had something valuable to contribute to my 993TT driving.

I appreciate the help!

Anir

Pat,

I just re-read your post, and noticed that you said the following:

"On most street vehicles, equipped with power brakes, you cannot effectively left foot brake as the vaccum assist is not present after the second or third pump of the pedal."

Does this apply to the 993s?

Thanks!

patr

Probably, if it has power brakes, but some turbo cars have electric vaccum pumps or other such things to compensate for a lack of vaccum, and as a side effect it makes LFB better too!

I don't have one so you have to try it:

(p.s. dont floor it because if you do you'll go too fast in that damn car, plus really high boost at low rpms aint so good either maybe...)

drive at 4000 rpm in any gear, at a constant speed, with foot on constant throttle (or pick any rpm, but dont make it too low as you want to be in the boost a bit)

now with your left foot, push on the brakes (in effect DRAG the brakes). Push soft, then without lifting the brake pedal at all, increase the pressure on the brake (every time you lift the pedal it is another stroke of the cylinder and you dont want to do that right now). When you increase the pressure, you will have to add a little bit more of gas to keep speed constant.

Now release the brake. You will accelerate hard if you also dont ease off the gas a bit (BUT DONT GAS COMPLETELY OFF). The best way is to slightly release throttle right before you let off brake.

Now try this a second, then third time, all between each time keeping constant pressure on the gas.

If your car has the power brake LFB problem, you will find that the second pump is harder, and on the third pump you have to STAND ON IT to make the brakes engage.

This is only on street cars with power brakes , most race cars have big master cylinders and no power brakes...

-Pat

Paul

Hi Pat

Could you please contact me off list. (This has to do with your experience as a factory driver.)

Thanks, Paul
gear@gte.net