If I want the most bias towards the back I can remove the valve entirely... correct?

My car's at the mechanic's and after bleeding the brakes correctly, the fronts lock up
with the "weight of a tennis shoe." (because of the big reds)

I have an adjustable bias valve I was going to throw in at a later date, but isnt it
just useful for controlling how much goes to the rear relative to the front?

 

Turbite,

Search my old posts on this matter. I put in Big Reds--too much front bias. I removed the bias valve (simply unscrew it and screw in the tube directly into the master cylinder), but this caused a reduction of overall braking ability at higher speeds with the back end locking up and want to swap ends (subtly, not uncontrollably). I then had an adjustable brake proportioning valve put in and love it. Wouldn't have it any other way.

 

Here's a pic

 

Exactly what I needed to know!

I guess next time I bleed the brakes; that thing is going in...

 

Why not just change the factory 18 bar bias to another factory unit? You can choose from 33,40,55,and 66 bar. I would think the 40 would be the one for your car, I have used it for that set up in the past.

 

I am waiting for my $50 Tilton Adjustable Valve to arrive..

 

I already have an adjustable...

Besides my impression is still that the bias valve only reduces the amount of power applied to the back. So at a certain low pressure it goes equally to both the back and front, but at a moderate level more goes to the front than back. At a high level, the back completely closes and it all goes to the front. (Again, I may be completely wrong about this, this is just my impression)
So using no valve at all is the best way to get more power to the back. So I'm still a little unsure how an adjustable bias valve help even if I set it to 100% open, isnt that just like no valve at all?

 

33,40,55,66 etc = % to the back when pressure applied > 5bar.

Therefore, "the back DOES NOT completely closes".

Go for the "33" or get the adjustable valves from wilwood or Tilton.

 

turbite, there's no way in hell you're ever going to want no valve at all, you'll lock the rears up and spin off the track every time you brake hard.

Sam

 

Songzzz:
Aahhhh... now it makes sense...
So no valve is a 100 valve

I've got the SSBC adjustable valve, looks just like David's.
They are probably all similar anyway.

Sam Lin,

Not with the stock back calipers, No way.
Those calipers are a joke compared to big reds.
Maybe If i had the stock front calipers on the back, but I don't.

I currently have no valve (I just removed it) and I still cant get the backs to lock.
(this is on the street with shatty street tires, but I don't see how it would be different with real tires)

 

Please. You will lock the rears with no bias valve. Take advice from people who've been there and know. You don't need big reds in back to lock up. You don't need the front calipers in back to lock up. The rears are plenty capable on their own.

If you don't believe it, feel free to stomp on the brakes at 100mph and let us know how it all turns out.

 

I used to have the stock front in the rear before.. no good, too much braking to rear even with the stock valve. Dont do it.

 

Interesting,..

My mechanic recommended for me to put the old front calipers in the back.
I wouldnt do this anyway, because I don't have them, but its nice to know i've got an optimal setup.

I could be getting more than normal front bias because the front tires are smaller and the front pads are better.

I just tried it. It turned out fine. (not at 100mph of course)

Do a search, You will find several people using no valve on the track
(Alan C and a few others). Contrary to your belief, the advice of the people who have been there and know is mixed.

I posted in order to get people's advice, When someone states something, with no personal experience, just hear-say, and I have evidency of the contrary, it deserves to be stated.

Furthermore, drop the punk kid condescending attitude.

 

Turbite, I'm sorry, I misread your initial details, I thought you already moved the front calipers to the rear.

Sam

 

part of your problem is the master cylinder bore is too small for the big red upgrade...you have too much hydraulic advantage on the front brake....


you should add the later 89 abs car /s4 brake master....its a simple job and radically improves pedal feel...i wont drive a car on the track without the upgrade...way to hard to modulate brakes on a non abs car.

frustrating