Anir

The most recent issue of Autocar (23 May 2001) has an interesting article on left-foot braking, as promoted by former rally driver Pentti Airkkala.

The article suggests that the technique may have originated with American stock car racers (e.g. Nascar). The article's author, Stephen Sutcliffe, was pretty flattering about the technique.

For the unitiated, here's the technique as I understand it: When braking for a corner, the left foot starts to brake while the right foot remains on the acclerator. As you turn in, the left foot stays on the brake to minimize understeer while the right foot gives just enough gas to maintain balance.

In mid corner, the left foot maintains some pressure on the brake while the right foot starts to acclerate towards the exit. It is suggested that the left foot's slight braking minimizes wheel spin.

Stated advantages: reduced reaction time (foot is closer to brake pedal if needed); increased efficiency by using brakes to basically influence steering; nose stays planted and tail wags less.

Do the majority of Supercup & F1 drivers use this technique? Is it better suited to oval tracks & dirt trails, or is equally beneficial for road courses and the street?

If I thought my right foot was clumsy, I hadn't seen anything until I started to try to use my left foot to finesse the brake pedal while maintaining accleration with the right foot! However, the technique intuitively makes sense to me since it might smooth the acceleration/braking transition in corners (less sudden weight shift from front to back or vice versa).

I might stick with it, if the consensus is that it's worth learning. My suspicion is that it may nicely compliment the AWD nature of my 993TT.

What do ya'll think?

Ahmet

My personal opinion would be that on an all wheel drive car, this technique wouldn't make too much sense, except for the transition smoothness part.

I've tried left foot braking a few times, and although I'm sure it would take some practice to do it comfortably, I don't think this is going to be my thing. I may try it a few more times before I decide, because I have noticed that even without much practice, transition from braking--> acceleration can be much smoother, and vice versa.

At least for now, my brakes aren't free, and they wear fast enough without using left foot braking... (I'm a student paying for my car/race expenses) The engine isn't too comfortable with hours on the track either... I'm sure some light modifications would cancel these annoyances, but then again I want to stay in stock classes.

OK, my 944 problems do not relate to your all wheel drive 993 twin turbo too much, so I'll stop with this, but you can get an idea of what I think about left foot braking (somewhere!) above.

Let me know what you think/find out, as I'm interested in this too.
Ahmet

belz

I too have been experimenting with left foot braking. It is not as easy as it sounds. However, my motivation has been less "stability" related and more to reduce turbo lag on my 951 race car. The stability issues you mention are upsides to left foot braking as well.
I have only nailed it a couple of times. There is a noticable increase in exit speed. I've attributed the increased exit speed to the turbo staying spooled up but your comments make me wonder about a combination of stability improvement and less turbo lag.

Adam Richman

Anir, although I had no idea of the root of left foot braking, it is something that I do regularly in a non-shifting corner on track. I am _NOT_ a professional driver and don't claim to know all of the benefits/downsides. What I have found was that after the initial part of learning to control pressure w/ the left foot, you can become as/if not more reliant on the left as right and I have more than once started with the left to pass off to the right to facilitate a gear change (if the left foot is all the way on the pedal obviously that can't happen). Point being, you can get comfortable with it to the extent that certain turns are w/ the left others w/ the right and that's that.

Another use of left foot braking and its pretty much when the pads/rotors/fluid are really not doing everything they could be is a tapping technique (I don't know the real name for it). If you are ever on track and you see someone's brake lights flickering like a strobe light down a straight, they are building pressure by tapping w/ the left on the brake before entering their brake zone while maintaining a wide open throttle. Surprisingly, it doesn't seem to affect acceleration but definately gets a high temp pad to grip in a hurry (this isn't something to try for grins nor with OE pads I would assume).

Whereas the latter isn't good on rotors or pads the former is relatively harmless (b/c there aren't _that_ many road course turns that you are going to be braking for and not shifting) IMO once you have the pressure issues worked out.

As to you're who else uses this question, watch some of the NASCAR guys w/ a foot cam during the road races - the tapping I spoke of is used there by a few (sorry I can't think of names).

As to being helpful w/ an AWD 993TT. I would always try to get a feel for anything that's availible (then again I track a 944S so do you blame me?) to me. I would say, worst case, get a good feel for it on empty streets (slowly and safely, until you stop putting your chin into the steering wheel) and if you never feel comfy enough to try it on track, you learned something that might apply to your karting future

My only advice, don't try learning to left foot brake in traffic or at the track.

Cheers

Adam Richman

belz, have you tried double clutching regarding the turbo lag issue? I keep trying to get a friend of mine to dedicate some attention to that for his 951. Just curious.

addictionms

I started to left foot brake about six months ago, and it really makes me wonder how I drove a car without it now. Every benefit others have described is true, so the value add I will pitch in is this...

practice left foot braking on local twisty roads if you have any, it is not so helpful in traffic, or on highways. I have heard it said there are four stages of learning

incapable and unconscious: I don know what I am to do and I am unaware if I am doing it

incapable and conscious: I know what to do, and I know I can't do it

capable and conscious:I know what to do and I am aware I am doing it

capable and unconscious: I know what to do and I do it without knowing

I suggest waiting for the second last one to introduce left foot braking to the track is the right thing, and wait until the last, capable and unconsious, before you try it in a race, which means your never will try it, you will just do it and later realize you did.

I know I followed that plan and now I left foot brake all the time and often I don't even know I am doing it.

Now I am working on double clutching, I am on the boarder of capable and unconsious...

keith

944 fellows - do you have problems getting your left over the clutch pedal to reach the brake? My clutch (951) is SO MUCH HIGHER than the brake, I have to jack my knee WAY up to clear the clutch w/the entire shoe when I try... with miserable consequences, of course. In fact, before the addition of a steering wheel spacer, I had to project my knee to the OUTSIDE of the wheel to be able to make enough ROOM to get my foot past the clutch pedal...
All I know is the superfast miata guys ALL left foot brake in AutoX, I've seen the results enough to know the benefits. I'm just wondering if my pedal are screwy in relation to each other (height wise) which is making the technique even MORE difficult to learn?

Ideas?

Adam Richman

I wouldn't think so personally, my brake pedal sits about 1/2" below the clutch pedal. I don't think I go over the clutch pedal. Rather, if my left foot is on the dead pedal, I bring it straight across the floor and up between the clutch and brake. I am usually only on it with partial foot.

Lemme verify

. . . (minutes later) . . .

Ok, I take that back (I'll leave what I had said due to the truth in advertising laws ) I had it half right. I do go over the clutch to brake but under it to get off the brake. I am only grabbing the brake with the center of the ball of my foot on the left side/corner of the brake pedal (that must be how I am switching feet under braking). When its on to full throttle, I let my foot allow the brake to come up as I slip my foot under the clutch to the dead pedal.

The reason why it must not strike me as difficult to get to the brake is that I go into a couple of turns knowing its a lefty. I guess that I get situated for it in advance. I would think in auto-x (I probably did this at my only one), as soon as I got my shift done, assuming a 2nd gear course, I'd have my left foot pretty much poised on the brake pedal. I should add that w/ normal seatbelts, this might not be as desirable (poised for the length of a run) as you will want to get that A framed body position w/ the dead pedal.

I am not saying this is THE technique, rather it's mine - usually that's in the category of "narry the two shall twain."

belz

Adam-
I'm not sure "double clutching" would help. I'm refering to a no-shift corner. Say third gear where your RPMs would drop enough, or you have to lift, thus loosing your boost.
By left foot braking ... one would not lift of the accelerator ... maintaining boost. Left foot braking here would have the added benefit of settling the car / maintaining boost / resulting in faster exit speeds.

[ 04-06-2001: Message edited by: belz ]

Adam Richman

Apologies belz, it was a tangential question I was asking based on the mention of turbo lag (not related to left foot braking). I am curious however if it does help overcome the lag . . .

JC in NY

My understanding is that most F1 drivers do use some form of LFB. There are variations on the theme.

addictionms

Left foot braking also puts additional stress on you the driver, since you can not have one foot firmly planted on the dead pedal, you really need to be firmly planted into you seat. If you are not planted inyour seat, your ability to modulate the two pedals is lost as will any benefit left foot braking might have brought you.

Left foot braking is really a balance between your two feet, I always think about the ball in the bowl on the hood exercise, smoothness is key, I have heard it said that a good driver can transision from gas to brake to gas without a passangers knowing it.

DJ

I left foot brake. Not all the time, and probably not half the time. I'm not sure how much I do it, because some of time when I do it, I don't realize that I have.

In certain specific turns, where the car pushes on turn-in, I'll give it a dab with the left foot, usually combined with a bit of throttle-lift.

There are some corners that I start out braking with the right foot, add the left foot to maintain pressure, and switch the right foot onto the throttle, dragging the left for a bit of trail braking combined with throttle on. I haven't put enough thought into why I do this on certain corners, so I don't know exactly why I do this, only that it seems to work. Thinking now about one corner in particular where I do this, it seems that when I don't do it, I run a little wide on the exit.

I know that at least some Indy drivers do (did) left-foot-brake. Years ago at my first racing school, Johnny Rutherford was there (his son was in the class). He talked about driving at Indy, and not lifting, but left-foot-braking to keep the boost up. So I tried it on the track. Spun.

It's a fine touch that needs to be developed, and your left foot is accustomed to pressing the clutch pedal quickly to the floor. Not exactly the motion you want on the brakes going into a corner.

[ 04-06-2001: Message edited by: DJ ]

keith

Totally off-the-subject, but I've had the opportunity to crew on an Audi S4 that young Rutherford co-drives in Speedvison World Challenge. Nice guy - I really liked him when I met him.

DJ

Johnny III (or is it Jr.?) was a very nice guy when I met him too. Quiet, and humble.