Proportioning valve
03-14-2017, 11:38 AM
#1
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Car: 1991 RS
Engine: 5.0
Transmission: 700r4
Proportioning valve
Getting ready to install a 4th gen 10 bolt and I'm converting to disc rear from drums. I have everything I need except the prop valve. Found these on ebay. Anybody use them? Any reason why I shouldn't? Price is nice compared to others, but I don't want to be too cheap on brake system parts.
http://www.ebay.com/itm/GM-Universal...3D322419344315
http://www.ebay.com/itm/GM-Universal...3D322419344315
03-14-2017, 02:59 PM
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03-14-2017, 07:14 PM
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Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Proportioning valve
Prop valves are vehicle specific to create the brake bias needed for your car. Don't just ***** nilly toss any prop valve in there without knowing how it will behave in your car.
03-15-2017, 05:28 PM
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Car: Base 91 'bird
Engine: 3.1 v6
Transmission: 4L60
Axle/Gears: 9-bolt 3.27 & PBR
Re: Proportioning valve
You may want to look at adjustable valves (Summit etc). I did with drum to disc conversion and it made a huge difference being able to dial up the rear braking beyond what a fixed valve would do.
03-15-2017, 09:33 PM
#6
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Re: Proportioning valve
You not have to change the prop at all..just try different spring in the stock prop.Your cheapest route for sure and reading the thread it seems extremely effective.I also choose this to increase rear brake pressure. I think the 19lbs spring in the stock prop might suit you..I opted for the 22lbs spring but im also converting to ls1 front brakes.
03-16-2017, 08:01 AM
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Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Proportioning valve
Just something to think about....
I have drag radials on the back of the car so rear traction is much greater than normal in dry weather, and much less than normal in rain. That causes a wild shift in brake bias depending on road conditions since my front tires are different. On dry roads I run the brakes almost to the max to create a decent bias so the car stops well. If I get caught in rain my rear traction goes to poo and that adjustable prop valve allows me to dial down the rear brakes so I can get home in one piece. It doesn't matter when braking easy, but it would matter if I had to do a hard stop in the rain.
I have drag radials on the back of the car so rear traction is much greater than normal in dry weather, and much less than normal in rain. That causes a wild shift in brake bias depending on road conditions since my front tires are different. On dry roads I run the brakes almost to the max to create a decent bias so the car stops well. If I get caught in rain my rear traction goes to poo and that adjustable prop valve allows me to dial down the rear brakes so I can get home in one piece. It doesn't matter when braking easy, but it would matter if I had to do a hard stop in the rain.
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03-18-2017, 11:54 AM
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Car: Base 91 'bird
Engine: 3.1 v6
Transmission: 4L60
Axle/Gears: 9-bolt 3.27 & PBR
Re: Proportioning valve
I did mine the easy quick way and mounted the valve right on the distribution block but if I did it again I'd go the extra mile and mount it somewhere on the tunnel. But my car is stripped out so doesn't have to work with the console or any trim.