Palting

The DE season is over in my neck of the wood, so I'm pondering the different techniques learned and implemented. Things like threshold braking, trail braking, weight transfer, controlled lift oversteer.

One thing I don't understand is left foot braking. So, you are on the gas, approaching a corner, and you brake with the left?? What does left foot braking do that lifting or braking can't achieve?

Bill L Seifert

I certainly cannt speak for anyone else, but I can tell you how I do it. It is not something I was taught, but something I have taught myself over 44 years of driving.

When on the track, the only time I left foot brake is when the gear I am going to use for the corner is the same I am in on the straight before the corner. If you were using an automatic transmission, then you could left foot brake all of the time, because you would not need your left foot for the clutch. I use left foot braking because then you do not have to move your feet around as much. I just keep my right either on the gas or poised above it, and my left foot is either on the brake or poised above it. It just saves miliseconds, but is easier, in my opinion.

On most tracks I run on, once up to speed, I only use third gear or fourth gear, which means I don't shift as offten as someone with a 6 speed gearbox, so if the gear I am in on the straight is the same gear I am going to use for the next corner, then I just keep my left foot above the brake pedal, and use it to brake. Obviously if I am going the downshift from fourth to third to go around the corner, then I don't left foot brake, cause I need my left foot to operate the clutch, and as dumb as I am, if I tried to left foot brake, I would probably get the pedals mixed up.

On the street, my truck is automatic, so I left foot brake all of the time, so it feels natural to me. Also, my second race car was a Formula 440 (Now called Formula 500), it had a centrifugal clutch, and a belt driven transmission, which was essentially an automatic transmission, so left foot braking worked well. Later when I started racing Porsches, I still left foot braked, when the above circumstances occurred.

I hope this helps,

Bill Seifert

1987 944 Race Car

wch

LFB useful IMO in a car with a sequential or other no-clutch shifter - you arguably can get from gas to brake faster. I also feel it can be useful in dealing with certain handling situations - for example, if the car is oversteering in medium speed corners, it may help to LFB smoothly against the throttle (both at the same time) to manage the weight transfer dance.

That said, for this 44 year old wannabe I think it's mostly a gimmick, I tried it because I heard about others using it, and then got used to it so it's no big deal. I suspect that, unless you're really looking for the last little bit of time, it doesn't make that much difference, there's so much more time to be made up elsewhere.

DJF1

On the prompt from a friend and fellow Rennlister I started this year playing with left foot braking. essentially when you brake you transfer the weight from the back to the front. So sometimes I use left foot braking to adjust the understeer during the corner. In other words I turn in and usually at mid corner I would be touching the brakes while on throttle as needed. I started doing this at very slow ( 2nd gear) corners, it helped tuck in the front considerably without upseting as much as a throttle lift the balance. So it works. It would also help a lot with trailbraking into a corner as you so not have to lift completetely so you can balance much better the weight transfer. I also agree with the previous posters that if you had a semi auto box to play with left foot braking would be the best way to brake all around. I first practiced a lot with my wife's auto car, to left foor brake you also have to be smooth and not jerky, having been used to push a clutch all the time your left foor is more attuned to slam the brake... so practice on low speeds first...

FSAEracer03

The more practical application of using you left foot has to do with a pretty damn hard techique. If you've ever rev-matched an upshift w/o using the cluth, you have a decent start. If you haven't here's how to learn how (and don't try this on a Porsche just yet!) Shift from any gear (preferably 1 or 3 due to the easier H pattern locations to the subsequent gears) into the next keeping as constant a speed as possible using the clutch as usual. Watch the tach and notice where the engine drops from and to while shifting (say 4000 down to 3100). Now do this again, but instead of using the clutch, gently ease off the clutch while you tug back on the shifter, when the engine is no longer doing any work on the tranny (or right before the tranny does work on the engine, aka engine braking) the shifter will fall out of gear naturally... now is when you place it into gear, and quickly.

You just upshifted w/o using the clutch! Ok, now never do that again, lol! That was a good exercise for rev-matching, but pointless in real life unless your clutch goes out. But it's pointless... use your clutch to upshift. But here comes the tricky part. Now that you have a hang of sensing where your engine revs go between shifts, reverse that theory. Watch the engine revs change as you DOWNSHIFT while keeping a constant speed. Do the same process for downshifting w/o the clutch, where you will now blip the throttle to the necessary engine speed and slide the shifter in place... and do this on a POS, as it is veerry difficult and will take a lot of practice!

Now as you might notice, you didnt use 2 of your 3 pedals, all you used was the gas pedal... hmmm. After you get this technique down, you can now use left foot braking at the track along with that to decelerate extremely quickly... faster, in fact, than heel-and-toe when perfected.

I only know one person who uses this method, but he actually uses it in daily activity. In his beemer, in his cobra, or at the track in a race car (he raced in the Rolex Grand-Am series in '02 and owns a race shop that I work at) he doesn't use the clutch to downshift.... it's absolutely insane to watch for the first time! He is very successful with it and still holds track records at numerous tracks.

Well, I hope that little essay helps the concept of left foot braking for ya ...oh, yeah... and as far as the balancing the car out in a corner idea, that works too, but in a RWD car, you can do that a lot better with a little something we like to call throttle-steer!!

Enjoy!

Palting

Thanks, all. I think I've got it. Seems more like a way to save time. Fractions of a second. Interesting.

wch

Palting, LFB v RFB is an old discussion. Advantages to LFB include timing, smoother modulation (as opposed to heel and toe) and maintaining car balance. Carroll Smith and others have discussed this, Smith pointing out the advantages. The shifting issue is pretty much moot w/modern shifters.

mds

LFB is useful on connected corners or ovals where you drive down into the corner on power and then slow. Lifting off and going to the brake causes too much weight transfer and risks oversteer unless you do it delicately. Smoothing out this transition with LFB helps.

oldtimer

Hi Palting, I think you have a good crop of responses already, but heres my 2 cents worth. In a 911 especially, good throttle control is paramount, your right foot belongs on that pedal and should rarely leave it. The left foot can be educated to dab and squeeze and caress the brake pedal, with practice , and now becomes an extra control for weight transfer in particular. All part of the fun....what's it worth in lap time ?......dunno, but if it contributes to better understanding of what the car is doing then it probably improves your limits.

FSAEracer03

lol, it's not a matter of being "moot w/ modern shifters." quicker lap times are never moot in racing... most people don't left foot brake in that manner b/c of fear of tranny damage, lack of know-how, or simple preference to heel and toe style.

The "issue" has nothing to do with the cars age or technological standpoint. It's left foot braking we're talking about here, not double-clutching (or double-DEclutching for you UK based readers )

SundayDriver

Left foot braking can be valuable in a production based car, even in a DE environment in some situations. For example, there are two places at Mid Ohio where I would LFB even in a street car. T1 to keep the car balanced, I would take flat in most cars, but LFB to take some speed off. T3 is a very light braking in most cars and you lose time moving your foot from gas to brake with such quick braking.

As far as clutchless shifting, I take exception to some of what FSAE is saying. First and foremost, it can be hard on equipment so I would not advocate that in a street car. Clutchless shifts are smoother when perfectly executed, but can abuse the gears when not well executed. Simply not worth the risk in a street car.

Second, my understanding is that you can not shift as fast without the clutch in a synchro box as you can using the clutch. I'll add that I have no personal experience, so I may be wrong. My car is non-synchro and I almost always do clutchless shifting (Up and Down). Even if it could gain a bit of time, why would you risk the gearbox at a DE (remember, that is the basis of the question that was posed)?

Finally, I disagree about clutchless shifting being difficult. It is very easy to do, and to do well in a non-pressure situaiton. In the pressure of a race, you will screw some of the shifts up and you have to decide if the potential damage is worth it. I think it is best left to non-synchro gearboxes, preferably sequential boxes.

chris walrod

there are many open wheel drivers that RFB, even though their left foot has nothing to do except being planted on the dead pedal. However, as I am speaking in terms of ground effect cars, LFBraking is advantageous as many LFBrakers will apply brakes before lifting to help settle the car and reduce pitch moments. Most of our Atlantic drivers LFB as its necessary on short ovals (Milwaukee, Chicago etc) where they run flat the whole lap and use some brake in the entrance of T1 and T3, again to settle the car.

I believe in production cars, where pitch moments are much greater, LF braking can be an asset. Turn 3 and 4 at Laguna Seca come to mind.

I have tried it some at autox where no shifting is needed and it feels really wrong and wierd. Just something to get used to...

BrandonH

Ross Bentley talks about LFB pretty extensively in his latest book (Speed Secrets, I dunno, III?) and basically concludes that young new pros who came up through karting have a huge advantage because of their highly developed LFB skills. Just after I read it, F1 Racing I believe the September issue, showed some pirated in-cockpit telemetry for both Schumacher and Barichello, comparing throttle and brake positions in different turns on the same track. Schumacher is on the brakes _constantly_ in the corner, and on both pedals almost all the time. The article shows how the speed differences add up corner by corner. Now another wrinkle for these guys is traction control: they can be WOT without melting the tires as soon as they are near track out. But at least in the corner entry and mid corner phase the contrast was fascinating. I'll bet LFB is to the current generation what trail braking was to Mark Donahue's.
Brandon

wch

"quicker lap times are never moot in racing"

uh ... pretty inciteful ... you're obviously the expert ...

Cheers,

Will
'00 360 Challenge (F1)
'03 Zeus (Hewland 6 speed sequential)
'03 FF2000 Zetec (recently sold)

Edit: I think Radical, Chris & Brandon pretty much nail it. Particularly agree about Mid Ohio T1, a hairy place to learn to trail brake though.

Z-man

If you drive a turbo, left foot braking can allow you to slow down, yet still stay on the throttle to keep the turbo in the "boost sweet spot."

So that is yet another reason to LFB.

-Z.