Just wondering... could there be an advantage to taking some tight autocross corners with a drifting "rally style" of driving such as in this video...

http://www.youtube.com/watch?v=zsmBVN39chQ

I really would like to know once and for all -- which way around is in fact the fastest way around?

If driving it normal is faster then why do rally drivers drift it even on the tarmac sections?

If drifting it is faster then why don't you see more other kinds of racers drifting it instead of driving it normal?

 

SCC tested this and found that a normal racing line was faster.

 

Drifting feels faster but the correct racing line actually is faster. Mostly.

There is some wiggle room in that statement with a turbocharged car depending on how you're driving - if the turbo is allowed to spool down through the turn, it is possible that staying on the gas (and keeping the turbo spooled) and drifting through the turn might be faster.

There are some other variables in there like the duration of the turn (sharp fast turn versus long sweeper), how far out of boost this takes the turbo, the driving surface, etc.

I'm sure there's a very logical reason why rally drivers drift most of their turns and F1 drivers never drift their turns.

 

If you watch that WRC drift video, every single one of them are drifting to scrub speed. I do the same thing on the track because you can avoid using the brakes and keep the turbo spooled. Any time you are sliding, you're decelerating, as you've overcome the tire's limit of adhesion.

 

thats not quite drifting is it... thats sliding until you are in the right speed and then you follow a line...

There is a reason you dont see F1 drivers drifting around turns... Grip > Drift all day long

 

I know when I have to slow down to take a turn, there is quite a bit of lag when I try to get going again. So assuming I could slide around the turn with the wheels spinning, I'd already (hopefully) be in boost when I got to the exit. Or at least have partial boost. I can see how it "might" be useful - like you said depending on the turn.

Higher power cars, like F1, don't need to do that because they already have a ton of low end torque. They just touch the pedal and it jumps.

 

The fastest way around a turn is actually with the rear tires just slightly over the edge of traction. There's a certain slip angle where a tire will make its maximum grip. Find that and its as fast as you can go. And yes, you do use this for autocross. On my fastest runs, the car is never completely gripping the pavement.

The reason that rally drivers drift is because that slip angle is higher when the surface grip is lower. On something like loose gravel, the best slip angle is very very large.

 

They also are not using pure street rubber and have restricted turbos, so on the tarmac they don't have great grip and need to keep the turbo spooled up.

And why wouldn't you do this at the autocross (even just for fun?)?

The same reason I don't -- TIRES COST REAL MONEY

 

Rally drivers also have anti lag systems, so maintaining boost isn't quite as difficult.

 

For rally drivers, the big slip angles also let them line up better for the next straight and give them a better preview of a blind corner...giving them options to modify their line as they are part way thru the corner.

Think of it like this: If you take the grip racing line and get 1/2 way thru the corner and there's something in your way (rock, crashed car, goat, etc.), you're not left with many options, either hit the obstacle or run wide off the road. In stage rally, running wide off the road often means you hit a tree or fence or go over a cliff.

Dave

 

a lil bit of over steer on corner exit helps the exit speed by rotating the car earlier & letting you get on gas sooner & harder.... when you max your car out on tarmac your sliding it, there is a fine line depending on tires.. but your sliding the car around...

not drifitng though, thas alot slower, but fun

 

You mean entrance right? The exit should be getting the power down, you don't want any more than the perfect slip angle for the tires (so you're right). If they are using big ol' squishy gravel tires, the slip angle would be pretty high and the traction would be relatively low, allowing for more oversteer. Again, the exit usually isn't the place for it, if you're going to use it (I assume) you'd want to get the car lined up before you're back to throttle.

Am I wrong?

 

Slight rotation through the corner is optimum as the car will essentially be 'straight' to the corner slightly sooner allowing for wot earlier. A large slip angle will get you into trouble and cost you time because of the old physics lesson that static friction is greater than kinetic and you always want more grip.

 

no.. your not wrong. different cars require different techniques.

i was specifically talking about the evo.... if your not in a slight over steer on corner exit the evo usually pushes real bad... specially on tighter radius / decreasing radius turns.

from our testing, its usually (not always) faster with that lil bit of OS.... & when I say a lil bit.. I mean a lil bit... though most my in car vids I am intentionally trying to get the rear end out cause its so much fun



n

 

I guess that makes sense with the Evo specifically, especially with it basically being a FWD car with help from the rear. This is probably also why most active diff systems in the Evo and other AWD cars put a lot of power in the outside rear wheel to stop the big, nose-heavy cars from understeering on-power.

And agreed about the sideways thing...