ryoung

In the "old" days, it was assumed that the skilled use of threshold braking resulted in shorter stopping distances than full ABS braking. Is this still true today?

With the high sampling rate used by the current generation of ABS systems, ABS only waits for wheel rotation to slow slightly before acting. I was wondering if ABS could now beat even the most skilled driver.

Warren Wang

It's very sensitive over bumps and in the wet. Too bad you can make the computer more aggressive, and let you get a little lockup.

Warren

WYSIWYG

hmm i never had the ABS kick in on the track, just one time when i went off the big bend sideways

jons355

Randy,

It is highly dependant on how the ABS system is made to work. In most street applications, as Warren pointed out, it wouldn't lead to faster lap times.

However, in the Ferrari Challenge series back when the 355 Challenge cars were running they did find that the fastest drivers were getting faster times with ABS.

Initially the 355 Challenge cars were delivered from the factory with the street ABS system and most drivers had them disconnected. However, in 1996 a new re-programmed system was installed on the cars and this system was much less sensitive and lead to faster lap times by the front runners.

I would venture to guess the really fast guys (F1/CART/ALMS) wouldn't need them. I have seen super slow mo shots of F1 drivers seemingly doing the impossible and regulating lock up braking from insane speeds.

I think in professional racing it won't catch on. Most professionals want to know they are driving the car not a computer. In F1 they are constantly debating traction and launch control. This year the CART boys banned traction control and it's the faster drivers who favored this.

Regards,

Jon
95 F355C
88 M5

ryoung

Senna did prefer ABS because it was quicker; and if he ran faster lap times with ABS, it must have been very very good. With all the downforce available to F1 cars, I'd think the ABS advantage would be greater. At high speeds with max downforce, brake bias ideally would need to be adjusted forward initially and then gradually shift back as speed and downforce decreased. It's one thing for the driver to adjust brake bias once if it starts raining, but it doesn't seem practical to adjust brake bias for every corner. With ABS, this problem is solved; the rear tires always provide as much braking as possible.

I'm not sure why anyone, Ferrari or otherwise, would have different settings for street and track. It seems the goals would be the same for both -- the shortest stopping distances with control.

LCP

...because you're not always in a flat level braking zone with a static load distribution. So you can go full on the brakes and not worry if the car gets a little light on a slight rise in the pavement that you'll lock up any of 1-4 wheels. ABS's ability to control braking to individual wheels is where it's at. Where Audi's ABS has problems though is on really rough pavement where small/medium defects in the road are bouncing the wheels out of contact with the pavement and the ABS gets confused and you end up with no brakes -- tracks are rarely in that bad of condition though as this is usually only something you'll encounter when exceeding the posted speed limit on a crappy road.