ABS to comp cutting brakes

Okay, I want to do something weird. Maybe it will work, maybe not. I've got a 97 XJ setup for rallycross competition. This is a trailered race car, no street use. I want to install dual handle cutting brakes plumbed so that one handle activates both right-side brakes, the other lefts. I'll probably use the CNC 452S. I need to choose the 5/8 or 3/4 cylinders. I'm thinking the 3/4 because I'm feeding two brakes. No need to lock the wheels, just drag the insides into the corner to help rotation. Will need some sort of residual valves to keep the volume requirements within reason. Light drag is no issue on a comp car.

But the main question is what to do for a master cylinder? I figure the ABS MC is too complex to try to mess with. I could retrofit to conventional power brakes. But I'm thinking maybe a single aftermarket MC also from CNC. It will have to supply all four corners so I'd probably plumb it with -4 hard line (clutch) to the cutter. Then -3 to the corners. Can't use powerful brakes on dirt anyway, so maybe I should use a larger bore, like 7/8. Again, residual valves will be critical -- especially with rear drums. I don't have any experience with those.

I'd like to hear from those of you who have done oddball master cylinder or cutting brake projects. Don't want to totally reinvent the wheel.

i wouldnt do both front and rear brakes for a turning brake. i have them on the rear of my sand car and that thing will whip around fine with just the rear tire locked. lock the front and i would think your steering control would be gone. have you done any research on locking both front and rear?

You're right, except I don't intend to lock the inside tires. Just brake them more than the outside tires to induce rotation on extreme corners such as hairpins. If I just cut the inside rear tire, the 4wd will require the outside rear to speed up (spin) or nothing will happen. If three tires stay planted, the fourth has to also.

Is your sand car 2wd or 4wd?

Research? Doing it now :compwork:

-- Picture request --

I bought the CNC vertical twin handle, 3/4" cutting brake. Plumbing seems easy enough. Looks like it came with fittings to adapt to standard 3/16" steel brake lines.

Am only going to hook it up in the conventional fashion for now -- rear wheels only. But need to decide on a location. I'd normally mount the handles next to the steering wheel, but that location is busy with the TC lever down there etc.

So I could mount it behind and on the passenger side of the shifter. I have the interior gutted and the console is off. I'll probably leave it off. But I would like to reinstall the passenger seat for fun runs and such when not in competition.

Where have you guys put your CB's in XJs?