Roen

iTrader: (2)

On the track, the only time I use left foot braking is when I'm exiting in the same gear that I'm entering in, in order to shorten the transition from brake to gas. I sometimes wonder, how do you efficiently apply left foot braking when coming to a corner that requires a downshift or two. With a traditional manual gearbox, how would you properly downshift while braking?

Mahjik

iTrader: (1)

You don't.

I've observed a lot of professional in-car foot cams over the years and most professional "Sports Car" drivers don't use left foot braking that manner. I highlight sports cars as prototypes and F1 style cars are completely different.

Most of them just use the left foot to prep the brakes before the braking zone or to settle the car on a bumpy track. Here's a good video of some footwork in a Porsche (even a little double clutch action):

http://www.aimsports.com/video/policastro2.mov

Mahjik

iTrader: (1)

Some good footwork:

http://www.youtube.com/watch?v=CWMuAAd24ao

Roen

iTrader: (2)

Strange, he likes to go 4-3-2 with only one blip of the throttle.

Coming off the long straight in the beginning of the Road America circuit, he goes 6-5-4-3-2 with only 3 blips of the throttle. Then in the short straight into the left hander, he goes 5-4-3-2, with only 2 blips of the throttle. It's like he couldn't move his feet fast enough for 3-2, either that, or he doesn't car, and his flywheel is really really light and his clutch is really really strong. No double clutching either, he forces the engine to spin faster by double tapping and slipping the clutch from 3-2.

I don't understand, if you're going to rev match 3 shifts, why not rev match the 4th shift as well?

I definitely use the left foot brake to stabilise the car when I run the simulations (i.e. video games). On the track though, my car doesn't have enough power nor is my suspension so stiff that I have trouble on bumpy surfaces, though I imagine next year, I will have to start.

Last time I used left foot braking, I ended up spinning since I carried 10 mph more than normal. It was a very cold day and the rear tires slipped midway through the corner upon throttle-on. Wasn't very fun, but I feel that if I could get that right, I could cut down a lot of my lap time, since this corner in particular leads onto the longest straightway. The track was Lime Rock Park in CT.

Roen

iTrader: (2)

Wow, those clutches engage so fast, and the flywheels are ridiculously light! The amount of time on each pedal is so much shorter compared to when I'm on it in my car.

Mahjik

iTrader: (1)

Keep in mind that the cars in those videos are using sequential transmissions. They don't really need that much of a blip on their downshifts. As you'll notice in the Mike Rockenfeller video that he doesn't use the clutch on the upshifts.

But back to you question, if you are downshifting and using a clutch, then you won't be left foot braking. That doesn't mean you can brake into the corner, and then as soon as your into the corner you quickly move your left foot back onto the brake pedal to finish the turn. There is a video of a guy doing this, but he basically just using the brake to correct too much throttle:

http://youtube.com/watch?v=R3O66igd0w8

If was wasn't applying so much throttle, he wouldn't need his foot on the brake. I doubt he's gaining much by doing it. I 'debated' with the driver on another forum and he agreed that using the brake was for 'corrections' not necessarily for 'speed'.

Roen

iTrader: (2)

I see what you mean, when I meant speed, I was referring to shortening the transition from brake to gas in corners where there is no need to shift. Also, the weight shift dynamics are subtly affected as well.

Are they sequential dog, or H-shift dog transmissions? I couldn't tell in the videos.

Mahjik

iTrader: (1)

Well, if there was a substantial advantage doing it; the Porsche factory drivers would be all over it. You can also look up the V8 Supercars from Australia videos and you'll see the same use of left foot braking. IMO, unless you are in a clutchless car; there's not much use for it outside of what the professionals are doing.

Sequential, IIRC.

Roen

iTrader: (2)

I think the reason why more people don't is that you would have to practice braking feel on both feet and as well as properly transition left foot braking to right foot braking with out messing up. I guess people don't think it's worth the risk to potentially mess up in a pressure situation and put the car into the wall. Maybe the simpler way is the faster way.

Still, any advantage is an advantage on the track, no?

Jeff20B

iTrader: (13)

I do left foot braking all the time. It's easy to keep a cold engine running when you're too lazy to set the choke.

Mahjik

iTrader: (1)

Mike Rockenfeller is (well was, he's an Audi Factory driver now) a Porsche factory driver. That's his feet in the YouTube video and you don't see him using it other than to set the brakes for turn and to steady the car. Now, I'm sure he does use it when he drive the Audi R10 LMP1 but as I mentioned above those cars are completely different animals than production based cars with clutches.

Basically, if you have to "think" about it, then you aren't being fast. i.e. if you are thinking about whether you should to use your left foot or your right foot for an upcoming turn, you are slowing yourself down. Like I said above, I'm sure those professional drivers would use it if it was worth it.

Sean Edwards, a professional driver http://www.seanedwards.eu/ , commented in another forum that there really is no speed gain by doing it. He said he does do it some on turns which do not require downshifts, but he said its just a preference thing.

Butter

Nice Vid . I tried left foot braking but I don't have the control over it like I do with my right foot.

stuntman

For those sequential gearbox cars... they don't have to use the clutch on the downshifts. You can left-foot brake the car and blip the throttle with your right foot to engage the lower gears. Some drivers (rockenfeller appears to be one of them) likes the habbit of braking with his right foot and dipping the clutch on his downshifts (which is better for the gearbox especially during endurance racing.

0.02

Roen

iTrader: (2)

I know, I was asking what one would do on a traditional manual gearbox

pacatkhp

Left-foot braking is very useful to stabilize your car in a corner and/or provide smooth weight transitions. However, I believe that in conjunction with a traditional manual gearbox it will only be a viable option during a down-shift scenario IF left-foot braking is second nature to you AND your footwork is up to it.

Case in point: Walter Roehrl, the rallye legend:
http://www.youtube.com/watch?v=Ts29KKhKXds

Just my two cents as views clearly differ on this topic.

Roen

iTrader: (2)

That's some bad *** footwork.

It's like I was saying, you have to switch back to your right foot to brake and downshift on the same time, but for corners that you don't have to shift on, you can brake with the left and drive with the right. You just have to make sure it doesn't make you slower, because you have to keep thinking about switching or not.

no_name

Left food breaking and manual gearbox makes me think rally racing. FWD rally drivers (and any other FWD driver) lives off of left foot breaking. FWD cars are nose heavy, consequently they understeer like pigs. If you left foot brake a FWD car it is sort of like pulling the e-brake. It helps compensate for understeer. You are essentially locking up the the back wheels and power overing the brakes in the front. Sort of like a Brake Stand on a RWD car. From my understanding of racing FWD cars you never take your foot of the gass. It is only a matter of how hard you are on the brakes.

In a RWD application shifting weight smoothly as previously mentioned is a major application. I supose you could also use it to induce understeer if you needed too (stabalize the car).

Roen

iTrader: (2)

Yeah, I'm beginning to think the major use is really to just stabilize the car over bumps (re: RX-7's). However, I still do think you can shave off that thousandth to hundredth of a second by left foot braking on corners where you don't need to downshift. (But that really is nit-picking.)

jgrewe

iTrader: (1)

Use it where you can do it smoothly. If you actually have to think about it, its probably slowing you down.

Its purely a personal preference with any driver. Two fast pro drivers I know have different opinions on it. Stu Hayner doesn't do it, he's fast. Bernardo Martinez(the 2000 Formula Mazda champ one, there is a couple guys with that name racing) uses it all the time, he's fast.

Usually a driver tries it and helps or it doesn't. Practice on the street to get your pedal feel. Hell, you can even eat with your left hand (if your a righty) and I've been told it will help your brain learn to manage file muscle movments on that side. Use the little smart muscles in your lower leg, not the big dumb ones in your upper leg.

Discokid

iTrader: (1)

I seen alot of pros left foot brake. I've even seen see tsuchiya use it, in the touge battle between the MCR Skyline vs the RE Amemiya FD3S

valmand

If you're good with the gearbox, you can actually downshift and use your left foot to brake at the same time. All you have to do is rev match with the gas pedal while you're between gears. I do this with my car on the street. Pull it off, and it results in a really fast shift. Mess up, and you might have to buy a new transmission. Don't practice this in a car you care about.

valmand

BTW, that touge battle between the MCR and the RE Amemiya was tizziiiiight

Roen

iTrader: (2)

But that means you'll have to pull the tranny out of gear when you're on the throttle, and you won't benefit from any engine braking, otherwise, you'll have to really force and yank the tranny out of gear while you're braking and most likely destroy your synchro's for that gear in one shift. I assume, with the method you listed above, you have youe left foot on the brake, the right foot on the throttle and no foot on the clutch.

ptrhahn

iTrader: (9)

I don't think LFB is going to save you much if any time on a standard gas-to-brake transition followed by long heavy braking and downshifting... where it is sometimes beneficial and time saving is when you need a quick gas-brake-gas transition, i.e.: setting up for corner that's not much slower than you're already going, but does require a very quick stab of brake to set the car up or slow it enough to be able to accelerate through the corner. I use it sometimes at turn 10 at WGI.

valmand

Roen, roger that. If your brakes are good enough (can consistently put the tires at the limit of adhesion without fading) there's no need to engine brake. But that's beside the point. You can still row through the gears with my posted method if you so desire. Immediately when you get off the gas, push the stick through neutral to the next gear. You won't need any pedal to disengage the clutch. And if you're really good at rev matching, you won't need any pedal to engage it either. Done perfectly, this will not damage the synchros. Done perfectly, you won't need synchros. But if you do mess up, it could be bad. Which is why you practice in a beater first.