roger zimmerman

Looking for further improvements for my DE RSA. Currently have S4 calipers with bigger rotors. Looking for changes in brake proportioning valve from stock. It used to be recommended to remove valve entirely??? Would CupCar line #964-355-315-70 replace valve? Or would different value valve help? Suspension consists of H&R springs on Bilsteins,standard size wheels/tires.Thanks!

Bill Gregory

Roger,

Did you do the complete upgrade, installing the 993/Carrera RS (same caliper) calipers in back?

The Cup line you referenced is NLA from Porsche Motorsport, btw. At a minimum, you may want to upgrade to the Turbo 60 bar bias valve. May not seem like a big change from your existing RS America 55 bar valve, however, it does shift some additional braking to the rear.

David K.

Try Pagid RS14 (Black) BRAKE PADS

Tom W

Roger, it's not quite clear what problem you are trying to solve and what constraints you have to work with. Like Bill's interpretation, it seems to me you want more braking from the rear. You've got three good options - make sure you have a caliper that's balanced for the front caliper (upgrade the rear too, if you havn't already done so), a minor tweek to the bias or use a more agressive pad in the back (assuming you are using OEM or Pagid orange now).

It's still not clear why you feel you need more rear braking.

roger zimmerman

Thanks for replies. Only ran 1 DE with this setup and it feels like all of the braking is happening in front. Pads are KFP Magmum Golds supplied by Paragon and seem to work very well now and in past stock condition.Calipers /rotors in back are stock RSA with above pads.I am a little disappointed with the upgrade because when it was stock with these pads it would outbrake nearly anything else.(on the street these pads will out screech/out dust anything made!)The main reason for the upgrade was to gain some more brake mass and not have to replace front rotors as often. (Twice a season with stock rotors being below min.)The turbo brake valve or different pads are a consideration but still would like more feedback! This car is driven not trailered to all events so it also must not turn into a monster in commutes to track.Car is not a commutor and is used strictly for DE/autocross.Thanks

Christer

sorry to hijack thread slightly, but does anyone have the part no. for the PV valve fitted on the Euro RS? I have RS brakes but after an emergency braking from 135 to 55 recently think itmight be an idea to make sure I have the same one...no major drama but it might be just as well to have the correct one installed...

tonytaylor

Has anyone fitte a variable bias valve to a 964?

David K.

Here's the VCI setup I run:
http://www.vehiclecraft.com/Brakes/vciweb7.htm

Front: 993Twin Turbo "Red" upgrade kit 13"x1.25" x32mm VCI rotors w/2024 Aluminum floating Hats

Rear: C-2 Turbo (not TT) rear calipers narrowed to fit the stock width rotors - this is what the factory did on the Carrera RS and the Carrera Cup cars. These calipers on the C2 Turbo are made to fit a 28mm wide rotor vs 24mm on the stock C2/4. And Cross-drilled 968 sport rotors (87-88 only) (299x24).

And completely removed the bias valve from the ABS unit.

For pads I us to run the KFP Purple 42F (which is even more aggressive then the KFP Yellow 42A "Gold"),
and switched to Pagid RS14 Black. The Pagid Black's have great modulation, better then the Pagid Orange's and more bite. After the switch to the Pagid I realized how bad the KFPs faded and had no grip. I us to have to bleed my brakes before every event with the KFPs, this was because they would overheat. The Pagid Blacks will not fad until they wear thin. I wear out a set of rotors every season with the Black's (25 days ~ 2700-3000 mile all on track).

David
http://www.rsamerica.net/gallery/davidk_of_nj.htm

David K.

Read this:
http://www.vehiclecraft.com/Brakes/vciweb7.htm

Bill Gregory

Here's all the numbers:

Model, bar, part number:

964 C2 to 1991, 45 964.355.305.00
964 C2 1992+, 55, 964.355.305.10
964 C4, 55, 964.355.305.10
964 Carrera RS, 55, 964.355.305.10
964 Turbo, Turbo 3.6, 60, 965.355.305.01

Christer

tonytaylor

The Tilton is the one I've seen used.

Thanks

Bill Verburg

As Bill said higher # on the p/v or remove it entirely.

W/ 993/S4 front calipers on 322mm front rotors used w/ stock rear rotor you want the 993 rear caliper and no p/v If a 304 front is used then the 60 bar p/v would be used.

There is no need to narrow a 965 rear caliper as that is exactly what a 993 rear caliper starts as.

Save the 965 rear for 28mm wide rotors. They are rare and special.

Here is a pic showing a 965 rear caliper(*same as 964 4 piston rear or 993 rear) and a 993RS rear caliper(*same as 993tt)


*except for piston and throat sizes

Burl

I just upgraded my RSA from stock bias to turbo bias. I use pagid orange and the car has a RUF cup suspension. It seems to be calmer under severe braking, especially trail braking. I do run 285's in the back and 235s in the front which I think allows the car to handle more rear brake bias. Anyway, simple change over, does seem to work.

My shop did not complete removal of the valve - what does that do.?



Burl
La Jolla
1993 RSA
2000 BWM Z8

Dunasso

It was my understanding that the 964 received the larger RS or 993 style rear calipers starting in 1993. The perportioning valve was also changed from the pre-93 setting of around 45% ratio ti 55% rear ratio. It seems that the valve or oriface size should be changed accordingly with the erar caliper upgrade to prevent the obvious. If in a racing application some experimentation should be explored for best ratio to co-ordinate with driving techniques/style. But I could be off here. Anyone know the exact specs? Duncan