anti trail brakers?

[Mr. NoSkills]

some of you i'm sure have been told that trail brakeing is retarded, some probably have been told it's good.
here is a pretty cool post you might want to look at...
http://honda.hybrids.jp/forum/showflat.php?Cat=&Board=alley&Number=119073&page=0&view=collapsed&sb=5&o=2&part=

[Weston]

That's left foot braking. I'm not aware of anyone calling it "retarded" or anything like that. It's a pretty well accepted driving technique and has multiple uses (induced oversteer, quick brake-throttle transitions, killing turbo lag). But it has to be used correctly and only when appropriate, and even then it may or may not be beneficial, depending on the car, course, and driver.

[Mr. NoSkills]

i've read/heard about a lot of schools and instructors that still tell their students "only brake in the straights".
the skip barber book actually talks a lot about how it's kind of a "heated" subject in a lot of racing circles but goes over the benefit of using trail braking.

[hsunchen]

Left foot braking and trail braking can be useful, esp. if you're in a car that doesn't rotate easily.

I'd prefer to have a car that handles close to neutral by itself, and concentrate on just conventional gas and brake inputs. This is because I suck and I don't need to make driving any harder than it already is for me.

It should be noted that on a turbo-laggy car like my MR2, left foot braking can be used to keep the turbo spooled while at low speeds/lower rpm's.

[marcrx5]

The reason they don't try and teach it in those schools is it is only a short class (3 days, maybe a week if you pay out the ass). They want you to focus on the more important things. Skip Barber also points out that the time gains are minimal here, so this is something experience drivers will want to work on to extract the most out of there laps. If you are beginning, you are going to want to focus on other things first.

[Weston]

"only brake in the straights" is the general rule, and something beginners really need to learn. Most of the inexperienced people I know will just go by their instincts and let off of the gas and/or hit the brakes when they feel they're going too fast through a turn. I did the same thing before I got into racing; it's your natural instinct to slow down when you're going too fast. If you're not pushing it too much, it's ok to do that (but do it smoothly and get back on the gas if it causes a problem). The faster you take the turn, the more dangerous it is to decelerate.

The exception to the "only brake in the straights" rule are advanced techniques such as trail braking and left foot braking. The reason for the rule is because deceleration encourages the car to oversteer (ie the back end loses traction and slides, which can easily turn into a spin). But sometimes you want to move the car's balance more towards oversteer... if the car is understeering (common in slow tight turns), a little induced oversteer will help make it more neutral.

And, like that article was talking about, left foot braking can be used to slow down without the delay of going from throttle to brake then back to throttle. Obviously, being on the throttle while braking will prevent you from slowing down as quickly as you normally could, but you shouldn't need to slow down that much in a turn anyway. Another benefit of doing this is the fact that it helps make the transitions between accleration and deceleration smoother, which makes it less likely to upset the balance of the car, and it's also easier to control the balance of the car with quicker results... if it oversteers, let off the brake and/or increase throttle. If it understeers, use more brake and/or less throttle.

The other use is for turbocharged cars to kill lag. We all know that turbos are powered by exhaust gasses, the volume of which depends on RPM and throttle position. If you let off of the throttle and/or the RPM drops, you reduce those exhaust gasses, so then you wont immediately be at full boost when you want to accelerate. The solution is to stay on the throttle while braking to keep the turbo spooled up, or get on the throttle a little before you stop braking to spool the turbo up. The RPMs will drop when slowing down, there's no way around that, but as long as you don't let the RPM drop too low and you stay on the throttle, it'll be ready when you want to accelerate.

But no matter what you use it for, it's an advanced technique, it needs to be used only when appropriate, and it may not work well for everyone. There's a lot going on when racing, so it can be tricky to do stuff like this. And if you need to shift too, it gets really tricky (but you generally don't shift in turns, of course).

[hsunchen]

Originally posted by Weston

The other use is for turbocharged cars to kill lag.

Silly Weston, I already said that! :p :D :p

[forum]

Originally posted by hsunchen
Silly Weston, I already said that! :p :D :p

well he did say that in his first post in this thread too...

Good topic though

[Weston-work]

He was just getting back at me for something I said in another thread. heheheh.

[HONDA GHANDI]

I think as with any style or technique its something that if you are comfortable with its ok. I have found in my S2000 it upsets the balance of the car too late in a turn causing it to push. In my ITR it made for some nice oversteer coming out of turns whick I liked. So really it has to do with the siuation you are in and the car you are in. I feel that the more tools you have in your toolbox the better driver you are. Even if its not something you will use or rely on its good to have that skill neatly tucked away for later use..

[stu]

Good thread, but just to be a little bitch. Weston turbo boost is dependant on load, not rpm and throttle postion.

[Weston]

Originally posted by stu
Good thread, but just to be a little bitch. Weston turbo boost is dependant on load, not rpm and throttle postion.

Well, it works the same for this purpose. Being on the brakes at WOT, would sure do it.

But that brings up a question... I've always heard that the engine runs differently when under load, but I know that the engine draws X amount of air at Y RPM and the throttle body can limit that... so you have a Z amount of air coming in and the ECU has to inject an appropriate amount of fuel, then it explodes and creates a certain amount of exhaust gasses. We all know that the turbo is run by exhaust gasses, which sure seems to be directly related to the Z amount of air.

What is going on regarding load that I'm not aware of? Does load somehow control the amount of exhaust per intake volume or something?

[HONDA GHANDI]

turbos are not driven by exhaust gasses. They are driven by exhaust HEAT. The expanding volume of gas in the manifold is what creates boost. Under load the heat in the manifold is greater than at the same rpm and no load.