I have another very easy question I'd like to add to my 20 Question blog for my friend Mark Utech. But I welcome anyone with experience on the subject to chime in. My question is regarding Left Foot Braking in High Performance Driving. I like to know how some of you apply it to get the results you want in various situations you're in on the race track. I do have some experience on the track with LFB on tarmac and other conditions. But since I've started doing it more on my simulator I'm very curious what others can teach me. Thanks a bunch!!! 1. What are the techniques you use? 2. Do you ever come across a situation where you need to apply LFB and Ebrake? 3. How does LFB effect FWD/RWD/AWD? 4. LFB in Karting, the brakes are on the rear drive shaft? 5. What are the benefits of LFB? 6. Is it faster to drive with or without LFB? 7. What are the conditions you'll need to make LFB work? Example: tires-low traction? Weight transfer? Initiate turn in?
to make it even more confusing for you, I use lfb not only for the weight transfer affect but to active different settings in my center differential. (center diff controller is programmable and brake and throttle are two of the inputs). but the intent is always the same, get through the corner as fast as possible lol
Ricetiva thanks for your response. Carl-very fancy smanshy technology you got on board. I was really impressed when I first heard about your setup from mr. Nuke.
In my RWD car I never used left foot braking. Put me in a FWD and its game on. I have rally crossed a couple of times and the ability to lighten up the rear end of the car via LFB really comes into play. Last week I was out in NorCal, I had a rental Corolla and was left foot braking on some of the hairpins on the Pacific Coast Highway (BTW turns out that car has a Yaw sensor). For AWD I don't have any input.
Well, there's a lot of little things going on and to use it or not use it will depend on what mix of things are going on. Left foot braking is something I have not really gotten into. I've toyed with it a little bit, but I've never specifically found enough need to do it for my own driving. Some things to think about: Left foot braking initiates weight transfer to the front of the car. However, throttle let off (partial or fully) also does this to a lesser extent. Depending on driveline slop, braking may be a quicker way to get weight forward even if only a little is needed. Also depending on the throttle (drive by wire), throttle inputs, including let off, may be sluggish. Left foot braking effects will be dependent upon the brake bias setup as well as any bite characteristics of the brake pads (different pad compounds front and rear). Left foot braking will be influenced by the drive platform of the car, fwd, rwd, awd. There may also be some computer controls associated with it too. Understand what the car does. Braking as with any inputs will use up some of the traction circle of the tires. Some go to throttle, some braking, some cornering. When you have both throttle and brake applied, torque will be transferred differently than with just throttle or brake alone. The accel and decel of the tire relative to the road surface will vary on all 4 corners. It will take time to understand how much of which inputs gets you the desired results. You will also have to decide if it can give you more or better results than you can get simply through throttle modulation alone or even let off and a tap on the brakes. Left foot braking has historically been described as being beneficial in time savings between moving the right foot between the gas and brake pedals. One foot on each can yield more instant inputs. There still is the matter of the car also being able to react fast enough to even take advantage of any reduction in time. A softly sprung car will be rather sluggish in moving weight around anyways. Left foot braking lets you stay on the gas, something the turbo folks like in order to keep the turbo spooled before coming back out of a corner. Some of this necessity may depend upon the turbo sizing. A small turbo will have very little lag anyways and not really require an attempt to hold boost through a corner. However a big turboed car can maintain a bit more torque on tap doing so. Consider brake wear and brake heat up through use of this technique. You are effectively at times both braking against the car and the engine trying to make power. I personally started toying with left foot braking back when I was dinking around with drifting. This was also a time I started learning heel-toe as well. I came to the conclusion, at least for me, that left foot braking just wasn't useful enough for what I had been doing. Yes, I did at times hop between gas and brake pedal over and over through a corner, but I could still hold an angle and line doing so. Many times through sport driving, I run a little more smoothly and simplify the inputs. I am seldom stepping between the brake and gas repeatedly. I feel it's more of the fact that the input sections are a lot smaller. Auto-x and rally-x courses have very short durations for inputs, so it's almost best to step the inputs down into a brake zone, throttle zone, or coast zone but not really anything terribly complex. The fine tuning of chassis balance is better suited when you're driving longer sections like big sweepers where the car has a much longer time to just sit there at the traction limit. Here you start finding yourself fiddling with steering and throttle to keep the car online as fast as you can go. The way my car is set up now, I really have no need to touch the brakes holding a corner. It's good enough to where I can just fiddle with the throttle a little and get the balance where I want it. When the car was more stock, I did find I needed to use more braking to get the front end to grip. In that time, I did have to step to the brake at times to tuck in the front end and help with understeer. I see left foot braking as an optional tool. It's something you can try and spend some time learning. However, I also see it as not being terribly effective unless you can already drive the car well without doing so. As with any technique, you should get to a point in your driving where you realize you need to do something different to get the car to move the way you want it to. It is similar to pulling the e-brake. You drive the car and need the wheels to do something different than what you can pull off with just the gas and brake. You need the torque or rotation speed different then what it can do naturally. You get start mixing in braking while on throttle or add e-brake and change the action at the wheels. Some people will also use e-brake with normal braking to modulate the brake bias dynamically as needed. I see left foot braking as a tool like this. It's simply another mix of inputs to get a different set of outputs that in certain situations is more beneficial than any others. You will have to figure out which situations those are. I know for me and the way my car is currently set up, I don't see a need at this time.
I know mt. Fuji likes to used LFB for boost Braking. LOL Thanks for the input so far. I used LFB for more than just weight transfer. I've used LFB to help me go around fast hairpins by keeping the throttle down while I ride the brakes with my left foot. And jabbing the brakes to get Nuke's Yellow Bugeye to come around while riding on tall soft snow tires in the middle summer. I've also used LFB on my Forester to work the understeer setting up for two to three consecutive turns in the winter. I've also used it to help tighten up on corner exit if the car starts to run wide. I guess I use it a lot when I think about it; especially on Subaru's, or just about anything I drive. I'll adapt to the situation and use what ever means necessary to get the job done at speed of course. I have found though the concept is similar the technique in which you apply these techniques will give you the desired results you're looking for. Some techniques will work better at track speeds. So I just got to Road America last night from a long day at BIR. I'll be here all week so I'll be practicing more LFB. LOL
