Steve in FL

This thread reminds me of an old joke in autocrossing circles: If you have a competitior that's starting to get close to your times explain the advantages of left foot braking to them and you won't have to worry about them again until next season.

jpm

Well, for what it is worth, IMVHO I still think this whole LFB business is the the biggest red herring ever, and indeed SteveinFL, you're right, it really is an old joke.
The saddest point is that so many newcomers think they need to master LFB to become quick, and it is absolute complete and utter bollocks.

Mark in Baltimore

jpm,

Have you ever tried this LFB business?

Bob Rouleau

jpm - If you mean that LFB is the secret to going fast, I agree. Once you have gotten good smiooth enough tto be quick and play with the balance of your car (I call it contact patch management) then LFB can add small increments of speed IMHO.

Best

jpm

Hi Bob and Mark; I do not mean to be in any way offensive; I'm delighted to hear of your commitment to LFB and that you can make good use of it.
My vehmence comes from the fact that from my observations from track days and race days, very few drivers are mastering circuit and car control basics in any case, that throwing in that LFB is a basic requirement, is just as I say, a complete red herring.
If the majority of drivers can simply get their car to the same (right) place at the same (right) speed for just two consecutive laps, then they would make perhaps some basic progress. But I don't see much of that and to ask them to consider the (dubious, narrow) benefits of any sort of LFB, is quite wrong IMVHO.
What's more, I would bet each of you that I could find more time in your circuit progress without LFB, by just concentrating on good disciplined approach to basic commitments; I only wish I could turn this into a feasable excerise.
I am convince threads like this, along with bar room motor racing, can do more harm than good, but of course it's extremely interesting nevertheless.
(It would in any case be great to meet you in person and argue the case.)
I'm perfectly happy to trade 'qualifications' for the above with anyone.

RedlineMan

JPM;

Of course you are correct in the strictest sense. After all... the gun is not dangerous. It is the person using it. If they have the training and mindset, they will be fine. If not, who knows?

You are making some erroneous assumptions as the basis for your argument. No one listed LFB as a basic requirement, and no PCA instructor in his right mind is going to tell a novice to intermediate student that he has to learn LFB. If he does, then he is called on the carpet if I'm the boss. WE JUST DON'T DO THAT. We have a pretty well defined system for what gets taught and what doesn't and that aint on the list!

LFB, Heel & Toe, Trail Brake, Cadence Brake, Chop-throttle Oversteer, etc are not things we teach at the track unless we are dealing with an extremely advanced student, and even then the list is not all inclusive. I do not teach H&T & LFB at the track. I will demonstrate, and we can try it on the access roads around the infield, but high speed events are not generally the place to learn this stuff. In all my years, I've only encouraged one student to try H&T. He was fair, but had to think too much about it. This fouled up the rest of his driving, so I told him to forget it.

Further, to insinuate that these advanced techniques would be taught before the fundamentals were mastered is simply not the case. NO ONE here would even THINK of delving into this esoteric stuff without first making sure the student could drive to a very high subconscious level.

I do agree with you that there are far too many "burgeoning hotshoes" out there who expend far too much energy regurgitating this kind of stuff when they can't drive there way out of a paper bag to start with. PCA does not run open track days where any yahoo can bring his mondo boogie rice rocket and drive like an F1 star. PCA makes sure they get instructors!

Bob Rouleau

JPM and Redline - hey we all agree. LFB is a very advanced technique which is taught only to the most advanced drivers. it is not *the* secret ingredient to going fast. If I had to pick *the* secret to gong fast it would be smoothness aka disturbing the balance of the car as little as possible.

Once you are close to mastering balance (I say close because a true mastery is probably a theoretical thing) left foot braking is a technique for tweaking the subtle fore-aft balance of the car. It is also very difficult to do well. I cannot imagine doing it in autocross at least none of the courses I've seen. On certain turns on certain tracks I use it and it took me several years to be confident. My feet and the layout of the pedals on a 911 made it an accomplishment for me at least. How Tremper does it with his size 15 shoes in a 914 is beyond me - but he is very good.

Regards

924RACR

Bob, I'll tell you right now, if you were to mess with the brake switch signal to the PSM ECU, there's a very good chance (depending on details of the layout and SW) that you'd end up shutting down most everything, leaving you with just brake proportioning and, maybe, ABS. I wouldn't recommend it.

Kinda sucks that they would not tolerate LFB in a Porsche! Sounds like someone (and I don't mean anyone on these boards) needs to learn how Porsches are driven in the real world?

Jim Child

I agree. I only mention LFB to advanced students, and when I do I encourage them to learn it on the street before they try bringing it to the track. Your left foot needs to be thoroughly trained and sensitized before you even think about trying LFB on the track.

Similarly, I don't try to teach H&T on the track. Instead I give it to students as homework. When I get a student who I think is ready to learn H&T I demonstrate it in my car, and I show them the footwork in the paddock. Then I give them a set of instructions that I've typed up and tell them to practice at home whenever they have the opportunity. Once they've mastered it on the street then they're ready to bring it to the track. I've had lots of students who have successfully learned H&T this way.

ColorChange

I'm in agreement with jpm. I believe a DAS (with integrated video) would be way more valuable in time savings to show if you are maximizing g sum, saving much more time than trying lfb (unless you're just doing it in certain easy situations). And those who try and argue against this can't, unless you have the data to show you are maximizing g sum, and then I will ask to see it. If you don’t have the data, you only have opinion (or a general idea what is happening – lap times, corner rpm exits, …). A DAS tells you much more.

SundayDriver

Can you explain what you mean by 'maximizing g sum'? If you are talking about miximizing the area under a g vs time (or distance) plot, I don't see how that directly relates to lap times. I will be happy to explain why I don't think that works, but I may not be thinking in the same terms that you are.

Thanks

DJ

I'm a left foot braker, if only just barely. In my 993, I did it pretty much like Redline described, starting off with right foot braking while downshifting, and then transitioning to left foot. I think of it as "adding" my left foot, then "subtracting" my right foot. Other than that, I used LFB in very few corners, mainly in spots where a slight lift would otherwise help turn-in, like a kink that could be taken "almost" flat. I can't LFB in my current race car, even though it's got a sequential trans and it would work great. My feet are just too big, and the steering column separates the brake and clutch, preventing my big foot from moving far enough to the right to get the brake. I can skew my ankle out to the left, and rotate my toe to the right for when I really feel the need to LFB, but it's very cumbersome and there's almost no feel that way.

LFB can help with making smooth transitions, or moving a little weight around, but it's only a tool, and one that is not absolutely necessary to really quick laps. Smoothness is the key to going quickly, and if you're not smooth without LFB, then you're not going to be smooth with it.

As to the comments about "You should never do two downshifts unless you are avoiding brake problems", well, that's JPS (just plain stupid). Skipping gears while downshifting is sometimes necessary, but most of these cars are heavy enough that you're on the brakes long enough to take your time, and catch every gear on the way down. It helps to keep the timing right, and to avoid getting the clutch out a tenth or two too soon and overrevving the motor. If you don't know what I'm talking about, or think that it doesn't make sense, then you're not driving it hard enough. Sure, if you're as good as Prost, skip all the gears you want, and you'll never make a mistake. I'm not that good, at least not at 10.0/tenths I'm not. And no one is talking about using engine braking to slow the car, that again, is JPS. The brakes on modern cars have hundreds, if not thousands of times the braking force of engine braking.

Rubens doesn't LFB but Michael does? I'm sure that there are other differences in their style besides just that, but in any case, when you're only a tenth or two slower than Michael Schumacher, maybe you should start worrying about the necessity of learning left-foot-braking.

mitch236

Recently, as I was practicing (on the street) LFB in my TT, I was doing a nice trail brake around a left hander when the motorcycle in front of me almost fell and I had to react. As my right foot came over and planted itself on my left foot I realized that I am not even close to being ready for track use. I may use it in low stress situations but for the edge, I will stay with RFB.

ColorChange

Sunday:

In another thread we were trying to describe the fastest driver. I think this is conclusively covered by saying the driver maximizes the area under the g sum curve as a function of time (subject to no racing considerations or unnecessary g creation). This encompasses line constraints.

DJ: I am in agreement with your LFB comments. But, I disagree with the following H/T downshift comments, especially a comment as strong as JPS. Here’s why I think you’re flat wrong.

You should never do a heal and toe (H/T) downshift on each gear when you are changing down two or more gears (unless your handling a mechanical issue). It is more reliable and less distracting to simply wait until you slow enough to catch the gear you want with one H/T downshift. I find it hard to believe that a driver that can do a H/T downshift at threshold braking cannot judge speed well enough to not over rev his engine. A H/T downshift at threshold breaking is not an easy task, and if you’re good enough to do that, I can’t imagine being bad enough as to not judge speed accurately enough to properly downshift. Maybe you can’t but I think most drivers could. It’s a lot easier to concentrate on threshold braking and downshift when you hit the proper speed once than it is to H/T downshift repeatedly while still having to hit the proper speed for the final H/T downshift. Simply less to do, easier to concentrate.

I agree, and as a matter of fact, Rubens is working on LFB. I think you should almost always LFB in a synchro tranny. I’m just not good enough (or simply have to wide of feet), to perform a two foot H/T downshift dance reliably to be worthwhile.

SundayDriver

In that case, I disagree and here is why...

Let's consider a nice, standard 90 degree corner. No funny surface changes, banking or anything else. Just a theoretically perfect corner. Since this allows a constant radius, the perfect geometric line will be the fastest way through the corner. No question that the driver who maximizes the g's on that line will be faster than the driver who does not.

However, this is not about being the fastest through one corner, but rather the whole track. Again, I will assume we are talking lap times, not racing conditions where you might take a defensive line to hinder a pass. Now it that corner leads onto a long straight, the fastest lap will NOT be generated by maximizing the g-sum through the corner (which can only happen on the correct geometric line). Rather, the fastest lap time comes from taking a late apex - giving up speed in the first part of the corner and then unwinding (giving up lateral g's and maybe total g's) on the second part of the corner in order to maximize exit speed. Now it is pretty basic that the driver on the correct geometric line will gain a bit on the late apex line for that corner. BUT the car on the late apex exits a couple mph faster and keeps that advantage down the entire straight away, resulting in the quicker time.

Same thing applies to a corner after the staight, but in reverse. In this case, you would tend to want to take an early apex and trail brake to extend the straight. Again, not the fastest way through the corner, but the fastest way around the track.

And that is all with a theoretically perfect corner. Change that to real world corners and there are many more compromises. I think it is an interesting idea to maximize g sum, though I don't think it works for fastest lap time.