Steve49841

I was thinking about brake bias adjustment on my 02 Z06. Was wondering if there is any more brake force in the rear tires and if it's worth the time and money to go after it. Is anyody doing this? and if so what system are you using. Thanks

davidfarmer

if you are running ABS, there is really no need to do anything. You would need to install a lever/know pressure bypass in the front braking loop, and those devices do not offer linear pressure reduction.

If you are thinking of going away from ABS, then you really need a dual master cylinder setup to properly balance your car.

Steve49841

DRM offers a master Cyl with a brake bias adjustment for $600 on their web site, thats where I got the idea. I wonder about the antilocks as they only activate when a wheel speed sensor detects a problem. I guess I don't see why adding more bias to the rear would affect the antilocks unless you added to much and locked up a wheel. I can see where you would need to be carefull on the street but my thought was it would be nice to have some control at the track especially if you went to a big sticky rear tire.

TedDBere

Quite a few vette guys adjust the bias with pad selection, FWIW.

jpobrien

DRM has a brake bias spring that they have tuned for the C5. I have their C4 version. Big difference when I put it in ... and only $13.

Bill Dearborn

You don't need to adjust the bias on 2001 and newer cars. They have dynamic rear proportioning and can add as much rear bias as the tires can handle. There is no front/rear bias differential set at the master cylinder and the rear brakes get as much pressure as the fronts. That is why the DRM brake bias spring is only sold for 97-00 models. Here is a description from the Service Manual:
Dynamic Rear Proportioning (DRP)
The dynamic rear proportioning (DRP) is a control system that replaces the hydraulic proportioning function of the mechanical proportioning valve in the base brake system. The DRP control system is part of the operation software in the EBCM. The DRP uses active control with existing ABS in order to regulate the vehicle's rear brake pressure.

The red brake warning indicator is illuminated when the dynamic rear proportioning function is disabled.

With DRP if your ABS system goes south on you it is very easy to lock the rear wheels under hard braking.

Bill

Steve49841

So with the DRP active control in operation it would make no difference what you do on the rear axle with tires and brakes, it is going to give you maximum brake force automatically. If I went to a larger tire/rotor/caliper/pad in the rear would the DRP automatically adjust the brake pressure to take advantage?

TedDBere

My understanding of the system is that it controls the pressure, not the grip. So different pads will grip differently at the same pressure. This is why many competitive vette drivers play with the "bias" through pad selection.

If your fronts are ABS'ing first then there is more stopping power available in the rear, at those brake pressures, so you can add a more aggressive pad to the rear, or a less aggressive one to the front, to get that additional stopping power to the ground before the front ABS kicks in. Same applys in reverse if the rears are ABS'ing first.

Steve49841

That must be why I read about some guys running different Carbotech pads on the front VS the rear. I run Hawk HP Plus and I don't think I have ever felt the rears go to ABS while the fronts have on several occasions. Which is what led to this thread to begin with.

Bill Dearborn

I can tell you this much. I had my EBCM go out on my 03Z while at Watkins Glen earlier this year and I had to be careful I didn't lock up the rear wheels while braking going into T1. I run 315s all the way around.

Bill