Saturday, March 24, 2012

LFB... the brakes are not made to make you go slower

well, not ONLY to make you go slower.

Quoting Mario Andretti, "It is amazing how many drivers, even at the Formula One Level, think that the brakes are for slowing the car down."

Of course the brakes will stop your car by dissipating kinetic energy (from the car's movement) into heat. But that's only half the story.

Welcome to LeftFootBraking.
A trained driver will be able to use it's left foot to brake. It's a hard technique and requires practice to master, mainly because you need to know when to do-it and train your foot to the right pressure.
It is however an excellent technique to make you go faster. That's right, braking will make you faster.

If you think about it, why would you need your left foot to brake? Why cant the right foot do -it? the answer is simple: because it's busy accelerating.

So LFB is used along with acceleration. WHY?
OK, When you normally brake, the car's weight shift towards the front and this will make the front wheels "heavier". That's why people at driving school teach you to enter corners under braking, allowing the front axle more weight and better grip.
When you accelerate, the opposite happens. The weight sifts to the rear of the car and the front end looses grip, widening your trajectory.

Some cars have a natural understeer tendency. And this doesn't need to be suspension setup. Just try a turbo FrontWheelDrive car and step-on in mid corner to feel it immediately understeer as the front tires give up on both steering ans gripping while also being pulled up by weight shifting.

What if you could have both? If you accelerate, but then brake just enough to maintain weight transfer under control (or even shift forward), allowing more pressure under the front axle and increasing grip. That's LFB.

In a powerful FWD car it's very important as the brakes will also "dame" the engine power and maintain control without decelerating (maintaining intake gas and engine movement inertia).

But this is not only true for FWD cars. Any car can benefit from this as it's directional wheels are at the front and braking shifts weight to the front.

For instance, my s2000. It's a rev2 chassis, so it has buil-in Understeer-under-acceleration to make the rear-end let-go more poised and predictable.
But I'm used to it and sometimes I'm counting on it to help-me steer the corner out under power with minimal steering and maximum grip.

By The Way: don't try this in a car equipped with the standard ESP. It will not understand acceleration with braking and shut-down your engine to emergency mode. IT'S DANGEROUS!!!! That's one of the reasons I hated the Audi A3.

Need proof?
I'm using this technique since 1997 and I normally do-so in some perfectly drawn bends I have on my Work-Home trip. I abuse the car so much on those right turn corners, that my tires are always rounded on the outside from the left side of the car and rounded on the inside on the right side of the car, as you can see here:

My rear right tire:

My Rear left tire:

(the inside is worn because of aggressive camber, but not as worn as the right tire was...also take a good look on the outside of the tire...it's rounded and worn-out)



My front left tire:
 


SOOOOO this should establish that those right corners are made frequently under heavy cornering (these were reinforced side-wall Falken FK452..not budget tires)
If I LFB under those corners (as I do), the left brakes pads would normally suffer a heavier load....
And here it goes:



It's clear that the brake pads on the left (front the front left wheel) suffer a lot more stress than the right wheel ones.