RedPhoenix

iTrader: (10)

Curious why no one does this. After upgrading to a 4piston front and keeping the stock 1 piston rears, why dont people change to the LS400 95+ proportioning valve?

masagsxr

I'm thinking no one has really tested this and just want to prevent the rear from locking up which is why they leave it the way it is. Anyone?

Questions come to mind.
How would you know how big to replace the valve with?
Will the brake booster be able to handle such pressure and will it need to be replaced?

Maybe its just too much time and research.

UpInTheLex

iTrader: (5)

Most people have ABS so it's not critical.
Most people would never be able to tell the difference.

Do you have info on how the bias is spread for either valve?

Is it a constant rate? Or is it a rising rate valve that sends more fluid to the rear the harder you press the pedal?

What do you want to achieve by using the LS prop. valve? Are you having a problem with your rear's locking up? You shouldn't... as you've already increased the front bias of the brakes.

That's not a concern what so ever. You're not increasing pressures, you're changing where it goes. Besides a brake booster is just a vacuum assist which aids your foot in pressing the pedal. The master cylinder is what dictates the fluid volume and pressures in the line.

RedPhoenix

iTrader: (10)

Actually it was the opposite, rears are barely being used. It was just a thought, seemed to make sense to use a proportion valve thats in a 4/1 piston car. I guess it doesnt matter. The only thing is that the ABS will be removed soon when the car is no longer the daily.

UpInTheLex

iTrader: (5)

You've gotta find out hard data on whether the LS prop valve allows more fluid to the rears. If it does you could replace it, but I doubt it will be worth the effort honestly.

The other thing to try is removing the prop valve and putting a T in it's place. You've got so much mechanical advantage on the front brakes that I just can't see a prop valve even being necessary. The fronts are going to outperform the rears easily.

See what I said earlier above. The only reason to use a prop valve is if your rears are locking up before your fronts. That causes the rear of the car to get unsettled during braking, oversteer conditions and spins.

There's no way to INCREASE the stopping power in a caliper by using a valve. It only allows you to dial braking power OUT of the caliper.

From the science standpoint you need to increase the surface area of the pistons in the rear caliper and/or use larger diameter rotors to match the change you've made in the front.

After that, if the rears are locking up before the fronts, get a adj prop valve and dial some of the rear brake out, until the fronts lock up just before the rears do.

UpInTheLex

iTrader: (5)

When you remove the abs, do the fab and plumb work and install a dual master cylinder setup with a balance bar.

Then you can dial your bias in however you want.



You can kinda see the balance bar in there. When it's straight across it's 50/50 F/R.

By changing the point where it piviots, it angles the bar and you can dial in 70/30 or whatever you'd want.

Hope I didn't bore you.. I'm a brake perv.

RedPhoenix

iTrader: (10)

Thanks for the info. I think I will focus on the dual master cylinder idea..

LiCelsior

iTrader: (32)

damnnn smart dude right there lol.