Aftermarket brake Proportioning Valve ?

[markup97]

Has anyone tried to install an aftermarket Brake Proportioning Valve into the ABS system on these cars? I want to dial in more rear brake bias for flatter braking and was thinking of this (as I do it with my Mustangs, which NONE are ABS).

Can it work with ABS or will I have to disable it and then fit the BPV into the system?

 

[steve]

i think you can change the proportioning in the current one

 

[chris2523]

and how would you do that exactly? i disagree, no stock adjustability.

front rear bias is mostly done with front and rear caliper piston sizes, and rotor sizes.
you can see this with the Cobra brakes. it moves the brake bias forward on the Mark viii.
the cobra has differently sized rear brake pistons to help move it rearward on that application.

on top of that, the Marks have a rear over-ride valve, that limits the amount of flow/pressure to the rear calipers, when you hit the break over point, the rears stop/slows increasing pressure. keeps the rear from locking or hopscotching around i suppose.
if you really want play around, i would start with removing that valve.

i don't know why it wouldn't work with the factory ABS system.

from the manual:

2014-01-16 15.21.02 by chris2523, on Flickr

 

[steve]

i think you can change it my changing the inside diameter of the fittings that screw in.

 

[markup97]

Interesting, the description and the pic. If this is so, I may have a valve failing then, as the car fiercely nose-dives when the brakes are applied. It appears as though the rear brakes barely apply (if even at all), with the complete lack of brake dust on my rear wheels as witness to this. I know the calipers at least extend mechanically as my parking brake works. Might get a complete new rear set of calipers and swap them on for troubleshooting purposes.

 

[steve]

i know when NJ use to test brakes for inspection i failed the proportion test, and this was on a 2 year old car. It was under the bumper to bumper, i took it to the dealer and they passed it, they just said the front brakes were doing most of the work.

I may be getting the adjust confused with the corvette i used to have, i just remember that by changing the inside diameter of the fittings changed the ratio, not that there was some sort of screw you can use to adjust them.