brake proportioning valve | Page 2 | The Z Club of Great Britain
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brake proportioning valve

Discussion in 'Rally & race' started by tel240z, Oct 4, 2015.

  1. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    Under the MC - unless you are rallying/racing. :thumbs:
  2. Turn & Burn

    Turn & Burn
    Z Club Member

    Apologies for dragging up an old post, but I’m keen to know how all this panned out.
    I’m doing an R32 front brake upgrade and am in the planning stage for the rear brakes.
    Most rear disc conversions seem to suffer from being underpowered, and will get more so with big discs up front, but Tel’s seem to be the reverse. This is a good situation in that its relatively easy to reduce rear power and as far as I know not possible to reduce front.

    I’d like to install rear discs but am concerned that the usual conversions (200sx caliper) will be retrograde, so will prob need a bigger piston/disc to increase power at the rear.

    What are people using and has anyone done any brake balance testing?
    Last edited: Jun 8, 2019
  3. franky

    franky Well-Known Forum User

    You'd be better fitting an inline adjuster wouldn't you? There was an fancy unused AP on ebay for not much cash, you can get a remote adjuster for it.
    Turn & Burn likes this.
  4. johnymd

    Z Club Member

    On my blue car I use the az willwood disks and callipers front and Dave Jarmen rear disc conversion. Master cylinder is the slightly bigger late 200zx kit. I have no adjustment for rear reduction. The fronts allways come on first and will lock before the rears. I have never had the rears lock before the front. I have locked the car up on many occasions on various race tracks I both wet and dry conditions. When I was using the car a lot I would get through a couple of sets of front pads a year and destroy 1 set of the upgraded willwood disks. I have only ever replaced 1 set of rear pads and I’m still on the original disks that came with the kit. This shows the front are doing most of the work but I like knowing that in an emergency the car is not going to swap ends due to too much rear braking. After 20mins on the track the front are generally smoking and the rears close behind and a very burnt and scored blue colour so are certainly being used but not as much as the fronts.

    My advice would be not to go for much on the backs and maybe use a willwood switched rate bias valve in the back line just in case you go too big on the backs. Use a similar but slightly bigger master cylinder that has near standard front to rear biasing.

    If you want an idea of how much bigger the fronts should be to the rears then look at some of the the saloon based race cars. Their rears are tiny single piston brakes as opposed to massive 8/10 piston on the front.
    Turn & Burn likes this.
  5. Turn & Burn

    Turn & Burn
    Z Club Member

    Thats really useful info, I was concerned about having too little brake at the rear but it sounds like I may be over thinking it and it’ll be fine as as. On ur DJ conversion what calipers and discs are being used?

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