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Old 05-14-2014, 06:05 PM   #39
CSG David
 
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Join Date: Aug 2012
Drives: S2000 CR
Location: California
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Quote:
Originally Posted by dradernh View Post
Dennis has certainly provided enough to keep someone busy for a week or two taking in all that is on his site. If nothing else, it will expose a person to many of the issues related to building a successful performance car. Not all of it, however, can be taken as gospel. (I know, big surprise.) For example, the following passage from this page: http://farnorthracing.com/autocross_secrets9.html

"But it was that little bump that was interesting. That bump indicates the area where a human can outbrake the ABS. If the driver is properly threshold braking, properly modulating the brake pedal force to stop just short of activating the ABS, he can stop the vehicle faster than if the ABS is actively pulsing.

My own testing proved it. On concrete, with race tires on, I could consistently outbrake the ABS system."

Not on my car. Period.

You must test this for yourself - using your car, with the tires and brakes you run at the track, at the temperatures at which they run on-track, and someplace where it's safe to do it (note that tracks generally prefer that you not engage in this sort of activity on their property).

I did it by running my car up to 70 MPH in 3rd gear and testing the brakes at the following "ABS levels":

1) Full-on ABS;
2) 3/4 ABS (i.e., full-on ABS immediately backed-down a bit);
3) 1/2 ABS (i.e., full-on ABS immediately backed-down halfway);
4) 1/4 ABS;
5) Just out of the ABS (as Dennis describes above).

My shortest stop is #2, and it's 6' shorter than #1. The others were longer stops than #1. This is on a car with an ABS ECU designed around a quarter-century ago. As always, your mileage is almost guaranteed to vary.

Moral of the story: trust, then verify - i.e., confirm for yourself as much as you personally can when being presented with seemingly factual information; a healthy curiosity/skepticism is a valuable aid as you work towards becoming your own expert.
Thank you for that blurb. This is what we do all the time. We are skeptical at claims, we test claims, we assess those claims, and then we validate and verify claims. We could very well change our position if we are proven that there is strong evidence of those claims. It does help that we have a large variety of cars to work with in Southern California.

On another note, suspension setup is more or less similar, but settings are always different. An AWD car cannot be setup the same was as a FR, MR, or FF setup. Likewise to other cars due to different wheelbase lengths, factory aero, and chassis stiffness.
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