[FASTFATBOY]

Mike Skeen at the wheel, those two Stangs are making some grits under the hood.

http://youtu.be/FKpWiT0A_9A

[mr.beachcomber]

Actually, I would say that it was the result of better threshold braking by Mike given equal braking capabilities between the two cars.

As a driver, you want to use your brakes to the threshold of lock-up and not activate ABS (which will result in longer, not a shorter, braking distance).

Once you've activated ABS, all you can do is stay on the brakes until the car slows down to the point where you re-gain control and by lifting off the brakes.

[StanIROCZ]

As a driver, you want to use your brakes to the threshold of lock-up and not activate ABS (which will result in longer, not a shorter, braking distance).

I suppose it depends on how good of ABS system you have and how good of a driver you are. When I talk to the new Vette and Mustang drivers they basically use the brakes as an on off switch and let the ABS do all the modulation. They also go twice as deep into the braking zone as I.

Without ABS you are limited by the tire with the least amout of traction (assuming your front to rear bias is optimized). If one wheel goes into a dip or goes over a smooth patch of tar it is going to lock up before the others which means you have to let up on the pedal. With a good 4 channel ABS it will pull pressure only from that one wheel while still maintaining the pressure to the others. Basically it acts as a 4 wheel LSD. I don't see how even the best driver can do better than that.

It is also very possible that Skeen knows his way around that track very well,.

[mr.beachcomber]

I suppose it depends on how good of ABS system you have and how good of a driver you are. When I talk to the new Vette and Mustang drivers they basically use the brakes as an on off switch and let the ABS do all the modulation. They also go twice as deep into the braking zone as I.

It sounds as if the Corvette and Mustang drivers you've talked with are making the same mistake the C4 Corvette drivers made when ABS became standard equipment back in the mid 80's. We thought that we could dive into a corner at higher speeds, brake later, and that ABS would take care of the rest. Didn't happen that way as once ABS kicks in one or more wheels is alternating between lock-up/free wheeling and braking thereby increasing the braking distance needed to whoa down the vehicle. Still, for the average driver, ABS will pay for itself the first time that it save's the driver from a nasty accident either on the street or track. That's why there's an ABS system on the 2012 ZR-1 for us street/track drivers while the Corvette C.6R race car doesn't have an ABS. (Nor do F1 cars, buts that's because I'm sure that there are systems out there like what you described below that can perform faster than a driver can react to locking brakes.)

Without ABS you are limited by the tire with the least amount of traction (assuming your front to rear bias is optimized). If one wheel goes into a dip or goes over a smooth patch of tar it is going to lock up before the others which means you have to let up on the pedal. With a good 4 channel ABS it will pull pressure only from that one wheel while still maintaining the pressure to the others. Basically it acts as a 4 wheel LSD. I don't see how even the best driver can do better than that.

Good write up and explanation of how a good system should work. I'm sure that there are ABS for racing that do just what you described, but I just haven't had experience with one that good on a street car yet; although I would like to try out either the 2012 Z06 or ZR-1 ABS just to see how well they function. (The 2012 Vette's Performance Traction Management system will allow the driver to turn everything off except the ABS.) Just based upon my own driving experience in a Z51 C4 and a C5 Z06, a good driver will always out brake an ABS using threshold braking. Still, would like to hear from any other auto-x/track drivers that rely upon ABS for their shortest/fastest braking performance.

It is also very possible that Skeen knows his way around that track very well,.

That's a distinct possibility too as Mike definitely knows his braking points at VIR very well!

[StanIROCZ]

It sounds as if the Corvette and Mustang drivers you've talked with are making the same mistake the C4 Corvette drivers made when ABS became standard equipment back in the mid 80's.

I don't think they are. I don’t claim to be the best driver and I know that I have a lot of time left in the braking and corner entry areas of the track. But one thing that is for sure is the C5’s and new Stangs are braking significantly later than I would ever dare. My limiting factor is a wheel locking up and I haven’t pinpointed if it is consistently the same one or not so it could be a mechanical issue.

American Iron racers will tell you that the new Stangs go ~100 feet deeper in the braking zones than they can. Because of this American Iron has put a weight penalty for ABS.

A friend of mine is an engineer for an ABS supplier has told me that the ABS does targets individual wheels. I know old ABS systems can be a POS and may not do this but I think the modern systems are very good.

Alan retrofitted a C5 ABS system on Ken Kurtz Formula and I believe they have noticed a big improvement. Maybe one of them will read this and confirm.

[nape]

American Iron racers will tell you that the new Stangs go ~100 feet deeper in the braking zones than they can. Because of this American Iron has put a weight penalty for ABS.

A friend of mine is an engineer for an ABS supplier has told me that the ABS does targets individual wheels. I know old ABS systems can be a POS and may not do this but I think the modern systems are very good.

Alan retrofitted a C5 ABS system on Ken Kurtz Formula and I believe they have noticed a big improvement. Maybe one of them will read this and confirm.

It depends on the corner, but the biggest advantage to ABS is that it will let you brake through turn in and you won't have one-wheel lockup like you might without it. Sometimes, that will let you go in deeper, but it won't save you if you go in way hot. It will save you if you are only moderately stupid though.

It's not an end all, beat all, but it does help a mediocre driver look better.