Brake bias valve
14 April 2004, 08:08 PM
#1
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Brake bias valve
Did anyone try this out : just remove the brake bias valve and let the ABS sorts things out...
I did it and brake performance is even greater, no locking up from the rears and flat and stable car when braking hard instead of diving into the ground...
(MY00, 4pots..., single pot rear)
Creepy
I did it and brake performance is even greater, no locking up from the rears and flat and stable car when braking hard instead of diving into the ground...
(MY00, 4pots..., single pot rear)
Creepy
15 April 2004, 10:20 AM
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How did you do it, what do you class as the brake bias valve?
Can the abs alter brake bias?
David
Can the abs alter brake bias?
David
15 April 2004, 11:43 AM
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And how safe and stable is the car if the ABS system shuts down for any reason? Suddenly the car behaves as if someone is pulling the handbrake on everytime you apply the brakes with some vigour. Not a fundamentally good idea, IMHO.
15 April 2004, 01:31 PM
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No, not exactlt, I will try to explain...
first of all, the bias valve is located on the suspension top on the left side when you stand before your car (that is on a LHD car..)
If you remove the valve, the rear brakes will get the full brake power, as by fully loaded car.
Because I have an upgrade (AP330 4pots), it is safe to upgrade the rears to maintain the brake-balance of the car.
I considered many options and this was the cheapest...
After several weeks of testing I can confirm that this is one of the best mods I ever did to my car (also the AP330's of course)
Within those few weeks, not one time locked the rears before the fronts, even in wet and greasy conditions...
And in the end, I can always put the bias valve back on... only 10 min. of work...
Creepy
first of all, the bias valve is located on the suspension top on the left side when you stand before your car (that is on a LHD car..)
If you remove the valve, the rear brakes will get the full brake power, as by fully loaded car.
Because I have an upgrade (AP330 4pots), it is safe to upgrade the rears to maintain the brake-balance of the car.
I considered many options and this was the cheapest...
After several weeks of testing I can confirm that this is one of the best mods I ever did to my car (also the AP330's of course)
Within those few weeks, not one time locked the rears before the fronts, even in wet and greasy conditions...
And in the end, I can always put the bias valve back on... only 10 min. of work...
Creepy
15 April 2004, 01:57 PM
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right then..
Moray Im with you on that.. but I am removing the abs on mine.. just not like that.
David
Moray Im with you on that.. but I am removing the abs on mine.. just not like that.
David
15 April 2004, 07:12 PM
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Moray, it's not that bad as like a handbrake pull. If I pull the handbrake, you defenitely notice that , 
.
I agree that this mod is not advised on cars wothout ABS.
When things go wrong, like the rears locking up or the backend of the car steps out in a corner when braking late, there is always the ABS safety net to sort things out.
And if my ABS fails, there is always the red warning dashboard light.
I'm considering now the installing of an adjustable valve (like in race cars), but still inside the engine compartiment, so relatively easy to fit...
Creepy
.I agree that this mod is not advised on cars wothout ABS.
When things go wrong, like the rears locking up or the backend of the car steps out in a corner when braking late, there is always the ABS safety net to sort things out.
And if my ABS fails, there is always the red warning dashboard light.
I'm considering now the installing of an adjustable valve (like in race cars), but still inside the engine compartiment, so relatively easy to fit...
Creepy
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16 April 2004, 11:10 AM
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My main point is about what happens when the ABS fails and you have to make an abrupt stop.
Sure, your ABS warning light will probably flag a failure, but do you really believe that:
A) the ABS would only ever fail at a non critical time?
B) In case of such an ABS failure, you will pull over and stop the car, getting the ABS fixed at the roadside or having the car transported to a repair agent suchthat you will not risk driving the car whilst the ABS is inactive?
C) Anyone else who drives the vehicle will be aware of the potential eventualities.
ABS equiped braking systems are designed from the ground up to be failsafe. You are proposing removing an extremely important part of these failsafe mechanisms and relying on the electromechanics and electronics of the ABS to not fail. That is a risk that I would not recommend or suggest taking on a public bulletin board.
Using an adjusted brake bias valve is a better idea all around, even though it could still carry an element of risk based on how well setup it is. In fact, if you have a properly setup bias valve, you should gain a lot of the benefits you mentioned with reference to readdressing the mismatch of brake capability caused by your uprated front stoppers. Maybe it would make sense to uprate the rear brakes too, thus reducing the imbalance and thus the level of mismatch that you need to adjust the bias valve for? Definitely better to have a setup that will remain predictible and stable in the event of ABS failure.
Sure, your ABS warning light will probably flag a failure, but do you really believe that:
A) the ABS would only ever fail at a non critical time?
B) In case of such an ABS failure, you will pull over and stop the car, getting the ABS fixed at the roadside or having the car transported to a repair agent suchthat you will not risk driving the car whilst the ABS is inactive?
C) Anyone else who drives the vehicle will be aware of the potential eventualities.
ABS equiped braking systems are designed from the ground up to be failsafe. You are proposing removing an extremely important part of these failsafe mechanisms and relying on the electromechanics and electronics of the ABS to not fail. That is a risk that I would not recommend or suggest taking on a public bulletin board.
Using an adjusted brake bias valve is a better idea all around, even though it could still carry an element of risk based on how well setup it is. In fact, if you have a properly setup bias valve, you should gain a lot of the benefits you mentioned with reference to readdressing the mismatch of brake capability caused by your uprated front stoppers. Maybe it would make sense to uprate the rear brakes too, thus reducing the imbalance and thus the level of mismatch that you need to adjust the bias valve for? Definitely better to have a setup that will remain predictible and stable in the event of ABS failure.
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