confused; adjustable vs. stock prop valve

[trumps2000]

Yea, I gutted it, basically now its a T fitting with an idiot light.

[6speedIROC]

My 86 GM manual has a great description of how the GM prop valves and MC work. I'll scan it and post it up here..

[6speedIROC]

From 1986 GM Shop manual..good info on prop valve and master...

[GMan 3MT]

Interesting thread.

I just purchased a Wilwood adjust. prop valve, lever type to install in the cockpit on the hump by the shifter. It is mentioned here and some other threads that you use the stock one or the adjustable one, but not both. Why is that?

During my last race weekend, I was locking up the rears. The Wilwood valve has adjustments from 0-57%. Wouldn't installing this inline with the stock one simply reduce the pressure to the rears 'stock+whatever the adj is set to'?

[alacran]

I like this thread. working on a 91 TA and wondering about the 5/8" plug modification to the combi valve.

Also, on the 91-96 b-body the cars came with drum or disk brakes in the rear but the combi valve was the same for both. On the rear disk cars the popular brake modification is to remove guts of the proportional valve (front of the combi valve) and just plug it. The goal is to make the brake force 70/30 front to rear instead of 90/10. It was so bad that the rear brakes did not wear just corroded from lack of use.

Also, on top of that metering valve was also modified to remove the delay. It was just trimming the plug in the rear portion of the combi valve IIRC.

This is a huge difference between f and b body. I thought the same would apply on f-body when updating the rear brakes like its done on b-body but the combi valves are different from the start.

So what is the plug mod for the third gen f-body? We need better stopping power to go along with vacuum pump on this cammed beast.

[neagan]

This brand new month's Car Craft Magazine just posted an article on why using a proportioning valve is usually not the best idea. It is an interesting read. Nitro-Nicky