Brake bias
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Joined: Sep 2002
Posts: 5,855
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From: Gilbert, AZ
DG -
I don't think you can transfer the brake pressure from the front to the rears. I had the same question months back and if my memory serves me right - It's non adjustable.
Edited Comment: You Learn something new everyday but, is this bias regulator swap good for all years/models?.
I don't think you can transfer the brake pressure from the front to the rears. I had the same question months back and if my memory serves me right - It's non adjustable.
Edited Comment: You Learn something new everyday but, is this bias regulator swap good for all years/models?.
Burning Brakes
Joined: Jun 2001
Posts: 778
Likes: 1
From: Herndon, VA
Your S4 comes with an 18 Bar 5.0 regulator. You can easily remove it and replace it with a 33 Bar 5.0 unit that was standard on earlier model 928s. There are also 45 Bar and 55 Bar 5.0 regulators that was used in some European Turbos.
Whatever you decide to use, make sure that the second number (5.0) is the same as the one you remove. YMMV.
BTW, I have the 55 Bar unit on my GT.
Whatever you decide to use, make sure that the second number (5.0) is the same as the one you remove. YMMV.
BTW, I have the 55 Bar unit on my GT.
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From: Southern New England
Drew-
<a href="http://www.nichols.nu/tip481.htm" target="_blank">http://www.nichols.nu/tip481.htm</a>
Ed-
Would you recommend the 55 for spirited street driving in an S4, or does it increase tail-happy behavior too much for wet-braking/cornering conditions? Thanks.
<a href="http://www.nichols.nu/tip481.htm" target="_blank">http://www.nichols.nu/tip481.htm</a>
Ed-
Would you recommend the 55 for spirited street driving in an S4, or does it increase tail-happy behavior too much for wet-braking/cornering conditions? Thanks.
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Joined: Apr 2002
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From: SF Bay Area
I went with the 33 bar bias valve. This still
gives me better overall braking, but less chance
of locking up the rears. It's a simple change,
just be careful not to cross thread the bias
valve when you install it.
gives me better overall braking, but less chance
of locking up the rears. It's a simple change,
just be careful not to cross thread the bias
valve when you install it.
Burning Brakes
Joined: Jun 2001
Posts: 778
Likes: 1
From: Herndon, VA
With the advent of ABS, it's highly unlikely that you'll lock-up the rears (or the fronts for that matter) unless the ABS is not working, or has been disabled (by pulling the fuse).
I've driven my GT with the 55 Bar regulator on the track and during autocrosses, in both wet and dry conditions. If my car oversteers, it's because I've induced it to do so, or I've messed-up. :^( The latter has been known to occur if I lift abruptly in a turn, or worse - brake in the turn when the tires are already at their limits of adhesion. In either case, I don't recommend you do that. ;^)
My front brake pads used to wear out three times more often than the rear pads. Since using the 55 Bar regulator, they only wear out twice as often. YMMV.
BTW, 1 Bar = One atmosphere of pressure at sea level (about 14.71 psi).
I've driven my GT with the 55 Bar regulator on the track and during autocrosses, in both wet and dry conditions. If my car oversteers, it's because I've induced it to do so, or I've messed-up. :^( The latter has been known to occur if I lift abruptly in a turn, or worse - brake in the turn when the tires are already at their limits of adhesion. In either case, I don't recommend you do that. ;^)
My front brake pads used to wear out three times more often than the rear pads. Since using the 55 Bar regulator, they only wear out twice as often. YMMV.
BTW, 1 Bar = One atmosphere of pressure at sea level (about 14.71 psi).
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From: New Jersey
Old&New,
Try the 33 first and then switch to the 55 if feel the need for more rear bias. I run a 55 on my GT. Really no issues on the street, but you have to be a bit more careful when trail braking on the track.
As Ed says...YMMV
Try the 33 first and then switch to the 55 if feel the need for more rear bias. I run a 55 on my GT. Really no issues on the street, but you have to be a bit more careful when trail braking on the track.
As Ed says...YMMV