left foot braking

Menchi · 03-14-2004, 08:35 PM

in initial D when tak races the EG6 a technique called left foot brakeing is mentioned that FF racers use to counteract the horrible oversteer that FF cars have. is this technique legitimate, yes, I know it's a cartoon. they say that he brakes while turning in to shift the wieght of the vehical to the front in order to swing the rear around, this is called a braking drift with FR cars but I don' t see how it would work in an FF vehical. the way I see it is that if you shift the weight to the front the car is more likely to understeer, well nevermind, I just don't get it.

driftxtreem · 03-14-2004, 08:48 PM

get ready

Menchi · 03-14-2004, 08:52 PM

yea, I expected that,

but don't really understand why, who cares where it came from. I hear from a friend who rally races it is a legit technique, but he can't quite describe why it works only that it does.

kaneda · 03-14-2004, 09:29 PM

left foot braking in a ff car shifts the weight to the side of the vehicle opposite of the corner you're entering and slows you down a bit, all of which allows you to turn faster.

ToplessFC3Sman · 03-14-2004, 09:32 PM

Well, hitting the brake while turning in a FR car transfers weight forward, thus taking it off the rear wheels, allowing less torque to spin them than if all the weight was still on them. Its a matter of friction really... u (actually mu) is the coefficient of static friction, and between the tires and the road it is constant (when the car isnt sliding). It equals the (force of friction/normal force)

u= Friction/Normal

The normal force is the weight the tires are exerting on the road, so in an FR car while braking and turning, the front tires get more of the weight, so the normal force increases, and so does the frictional force, allowing the front to grip more, while the back tires have a decreasing normal force, which decreases the frictional force. The frictional force is what keeps the wheels from spinning, and if it goes down, it takes less to spin them... Now for an FF car, theres no problem with spinning the rear wheels, but braking still shifts weight forward, increasing the traction of the front tires...UP UNTIL A CERTAIN POINT. Too much brake and you could either :

A) take too much of the tire's friction and turn it into braking force, in which the car stops faster, but IT TURNS EVEN LESS than normal, because the frictional force which would normally go into turning becomes force slowing the car down... or

B) lock the wheels and just slide, in which there is a different (and smaller) coefficient of friction, the coefficient of sliding friction. And since its smaller, you get less frictional force for the same amount of normal force, and thus less turning...

Both these apply to both FF and FR cars... and for each there is a happy little middle-ground where some braking will give you more turning than without... it just involves experimenting in a nice big parking lot or something

Menchi · 03-14-2004, 09:37 PM

ToplessFC3Sman

dude, your a genious, thank you. that will definitly improve my driving

lv2drft · 03-14-2004, 09:53 PM

i use left foot braking while racing cars that dont have clutches... either autos or clutchless manuals. that way you dont take time to get back to jamming the accelerator to the floor. but the physics explanation was good too.

Drift For Food · 03-15-2004, 05:30 AM

Mmm physics, fun stuff. Good explaination. ToplessFC3Sman and lv2drft basically have your explainations. Braking adds grip to the front tires and left foot braking eliminates lag time between braking and throttle since you can manipulate both at the same time.

plinker · 03-15-2004, 05:54 AM

>left foot braking eliminates lag time between braking and throttle since you can manipulate both at the same time.

right. leftfoot- braking is about the precise weight transfer
and you can do it quick.
but the way you do it is different depending on which surface you drive and type of your driving.
leftfoot braking is basic for gravel/snow rally type driving
but if it's circuit, some drivers use it and others don't.

other purpose of leftfoot braking is reducing turbo lag
(someone already mentioned this in an old thread)
and another is lighting the brake lump to pretend you're slowing down
without actually slowing down. and hey, it's fun to fool someone behind you!
but this works only once and doesn't work for a good driver.

plinker · 03-15-2004, 05:57 AM

>FF racers use to counteract the horrible oversteer that FF cars have

this doesn't sound like right situation for leftfoot braking.
that driver will spin out even faster.
leftfoot braking is basically about eliminating the understeeer.
or are you just confusing those two?

03-15-2004, 11:35 AM

when i use left foot braking in my FF i tap it just enough to throw the weight forward... then i pull the e brake a little the break traction in the rear... i usually brake right before the turn while im turning the wheel to the left so i have time to break the rear for the turn... then when the back slides around i counter steer just enough so that the front wheels are pointing toward the straight so i can floor the gas and use e brake to contol the back end from regaining traction too quickly... keeping the gas floored keeps it from rotating too far and causing something bad to happen. i usually do this at an entry speed of 45 and an exit speed of 35-40 instead of an exit speed of 20 with no drift... oh and the recommended speed for this turn is a measly 15 mph... hah yeah right...

HX-50 · 03-17-2004, 11:45 AM

Quote:

Originally posted by ToplessFC3Sman
Well, hitting the brake while turning in a FR car transfers weight forward, thus taking it off the rear wheels, allowing less torque to spin them than if all the weight was still on them. Its a matter of friction really... u (actually mu) is the coefficient of static friction, and between the tires and the road it is constant (when the car isnt sliding). It equals the (force of friction/normal force)

u= Friction/Normal

The normal force is the weight the tires are exerting on the road, so in an FR car while braking and turning, the front tires get more of the weight, so the normal force increases, and so does the frictional force, allowing the front to grip more, while the back tires have a decreasing normal force, which decreases the frictional force. The frictional force is what keeps the wheels from spinning, and if it goes down, it takes less to spin them... Now for an FF car, theres no problem with spinning the rear wheels, but braking still shifts weight forward, increasing the traction of the front tires...UP UNTIL A CERTAIN POINT. Too much brake and you could either :

A) take too much of the tire's friction and turn it into braking force, in which the car stops faster, but IT TURNS EVEN LESS than normal, because the frictional force which would normally go into turning becomes force slowing the car down... or

B) lock the wheels and just slide, in which there is a different (and smaller) coefficient of friction, the coefficient of sliding friction. And since its smaller, you get less frictional force for the same amount of normal force, and thus less turning...

Both these apply to both FF and FR cars... and for each there is a happy little middle-ground where some braking will give you more turning than without... it just involves experimenting in a nice big parking lot or something

What he said

S13_Steve · 03-17-2004, 12:01 PM

its all about the g force and how lucky u are

Menchi · 03-17-2004, 03:46 PM

Quote:

Originally posted by plinker
>FF racers use to counteract the horrible oversteer that FF cars have

this doesn't sound like right situation for leftfoot braking.
that driver will spin out even faster.
leftfoot braking is basically about eliminating the understeeer.
or are you just confusing those two?

a friend of mine pointed that out and I forgot to fix that, I meant understeer, sorry