Brake proportioning valve help needed
#1
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Brake proportioning valve help needed
Car is in the shop for some of the final upgrades and maintenance. I needed new rotors and calipers probably needed rebuilt, so I decided to upgrade. After doing tons of research, thanks especially to Bill Verburg for tons of shared info, I still have a question on which, if any, p/v should I use.
I have an 89 C4 that is set very low and stiff with JIC's, running 7.5, 9 x 17" wheels with street tires(non R compound). I will be using 928S4 fronts with 304x32mm drilled rotors and drilled standard sized rears with a 993 30/34 caliper. I don't do any tracking as of yet, but may this year.
Any experience with this setup and what works or doesn't would be appreciated.
Thanks in advance!
I have an 89 C4 that is set very low and stiff with JIC's, running 7.5, 9 x 17" wheels with street tires(non R compound). I will be using 928S4 fronts with 304x32mm drilled rotors and drilled standard sized rears with a 993 30/34 caliper. I don't do any tracking as of yet, but may this year.
Any experience with this setup and what works or doesn't would be appreciated.
Thanks in advance!
#2
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I have 928 GTS (same as 993TT - not S4) set-up in the front on the 993 C2 caliper in the rear. The stock proportioning valve is great and I didn't touch it. Best part is that front and rear brake pads wear evenly, i.e. get always replaced at the same time. I use the car mostly on the track and it is an RSA.
For more details see here:
https://rennlist.com/forums/964-foru...e-upgrade.html
For more details see here:
https://rennlist.com/forums/964-foru...e-upgrade.html
#3
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Thanks for the reply, good info on the pads, but your car is naturally more front biased than mine will be with your big reds/blacks vs my mediums on smaller rotors. Maybe I will need less rear biasing?
#4
Drifting
Replace it with a Turbo valve, think it's 55 bar. Part.no 965.355.305.01
I did this at first, but later on I removed the valve all together and just connected the pipes without the valve as they did on the Cup cars. Works even better. Makes the car more stable under hard braking and the pad wear is more even front/rear.
Thomas
I did this at first, but later on I removed the valve all together and just connected the pipes without the valve as they did on the Cup cars. Works even better. Makes the car more stable under hard braking and the pad wear is more even front/rear.
Thomas
#5
Car is in the shop for some of the final upgrades and maintenance. I needed new rotors and calipers probably needed rebuilt, so I decided to upgrade. After doing tons of research, thanks especially to Bill Verburg for tons of shared info, I still have a question on which, if any, p/v should I use.
I have an 89 C4 that is set very low and stiff with JIC's, running 7.5, 9 x 17" wheels with street tires(non R compound). I will be using 928S4 fronts with 304x32mm drilled rotors and drilled standard sized rears with a 993 30/34 caliper. I don't do any tracking as of yet, but may this year.
Any experience with this setup and what works or doesn't would be appreciated.
Thanks in advance!
I have an 89 C4 that is set very low and stiff with JIC's, running 7.5, 9 x 17" wheels with street tires(non R compound). I will be using 928S4 fronts with 304x32mm drilled rotors and drilled standard sized rears with a 993 30/34 caliper. I don't do any tracking as of yet, but may this year.
Any experience with this setup and what works or doesn't would be appreciated.
Thanks in advance!
#6
Racer
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Thanks Bill, I didn't realize they used a different one for the 993's. I guess I'll start stock and go from there, then maybe to the 40.
If anyone else has comments that is using my setup, I'd still like to hear them.
If anyone else has comments that is using my setup, I'd still like to hear them.
#7
Replace it with a Turbo valve, think it's 55 bar. Part.no 965.355.305.01
I did this at first, but later on I removed the valve all together and just connected the pipes without the valve as they did on the Cup cars. Works even better. Makes the car more stable under hard braking and the pad wear is more even front/rear.
Thomas
I did this at first, but later on I removed the valve all together and just connected the pipes without the valve as they did on the Cup cars. Works even better. Makes the car more stable under hard braking and the pad wear is more even front/rear.
Thomas
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#10
You have to remember the your setup is not the same as the op's, you have much more front bias due to the 322mm rotors vs the op's 304mm rotors. Your's are essentially(at least closer too) 964RS/Cup. The Cups eliminated the p/v for track use.
#11
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Marc
#13
Burning Brakes
...but someone like the good Dr Alex will doubtless chime in with some proper tech-science stuff
#15
Burning Brakes
Where does that put the rest of us then!?
Isn't the idea that the proportioning valve stops too much pressure going to the rear and thus locking up the rears?
I'd imagine it's a 'safety' factor for the road, hence not required when on track where brake bias/balance is affected by many more variables, whcih you set the car up for on a per track basis anyhow?
Isn't the idea that the proportioning valve stops too much pressure going to the rear and thus locking up the rears?
I'd imagine it's a 'safety' factor for the road, hence not required when on track where brake bias/balance is affected by many more variables, whcih you set the car up for on a per track basis anyhow?