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Discussion Starter · #1 ·
I can't find info on the proportioning ratio of the stock master and whether the ABS unit has a proportioning valve inside of it. I'm trying to calculate brake distribution of the stock system so that I can figure out a proper rear upgrade path that gets a better distribution changing out as few parts as possible. Any info along these lines would be most appreciated. :)
 

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Discussion Starter · #10 ·
I'll only answer these quickly:
1. I know the possible solutions, including the front caliper on the rear. I'm trying to figure out the math so I can actually calculate what the right answer is instead of blindly trying things.
2. If you're overwhelming the stock brakes on the street, either you're driving well over 100mph and stopping to 50mph many times a minute, your brakes are completely broken, or you're not running the right pads.
3. The car will eventually be a national-title-contending autocross car. "Good enough" isn't what I'm looking for, "the right answer" is.
4. Prop valves induce a knee in the curve. I would much rather fix the actual base bias, not introduce second order variables into the mix.
 

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Discussion Starter · #13 ·
Unfortunately, I cannot help you with the math but, the only way to address the base brake bias issue is to either; a)increase the the caliper size at the rear or b)remove the entire ABS system and plumb the rears with your own proportioning valve(in which case you may still need to increase the the rear caliper size). The current ABS system contains no magic, in fact, it is a very simple ABS system and is not suited for competition use. I use a front on rear setup but, I need to obtain the AP calipers that have the slightly smaller pistons (43.5 mm). I feel the stock fronts on the rear is just a wee bit too much rear. I'm not a fan of staggerring brake pads for comp applications as they just tend to warm up at different rates which is an issue in and of itself. There has to be someone on LT that can do the fluid math for the factory piston sizes front and rear (I always had to defer to a race engineer pal in the past for my racecar).
Exactly. I'm just trying to do the math so I can see what the right size rear piston is. Good to know that you found the smaller piston as the right answer, since I was figuring that just using the normal front caliper in the rear seemed like a bit too much of a change.

Where did you get the smaller-diameter piston version of the AP caliper? AP proper, or is it an application on another car that's easier to find?
 
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