Brake Proportioning Valve

tasroadster · Postby **tasroadster** » Tue Apr 04, 2006 6:45 pm

Has anyone tried to eliminate this valve? (divert it)

It should give a better bias to the rear brakes.......right?

Any help would be greatful.

Thanks

sabretooth · Postby **sabretooth** » Tue Apr 04, 2006 6:59 pm

Is that a legal mod?

Why would you want to do it anyway?

CT · Postby CT » Tue Apr 04, 2006 10:19 pm

Trust me - you can't remove it without stuffing up your front to rear bias - badly. Matty has written of using a later model valve on earlier cars. If you are really stressed, start playing with rear pad compounds or open your wallet and get an adjustable one fitted in it's place.

tasroadster · Postby **tasroadster** » Wed Apr 05, 2006 9:00 am

Is an adjustable bias valve legal?

Thanks

Matty · Postby **Matty** » Wed Apr 05, 2006 9:38 am

tasroadster wrote:Is an adjustable bias valve legal?

Thanks

I believe it should be, if it's not mounted in the cabin. (ie replace the OEM one under the bonnet). You'll need a few adaptor fittings to make it all work.

Removal of the valve entirely would probably be unsafe, though I have heard of it done with good results for autocross use (the fronts were still locking up first). Do so at your own peril and with no approval from me. Search the big forum...

As said, I have an NB prop valve on my car which made a noticeable improvement in braking. part number is NC10-43-900A but you'll have to order it in. It will probably cost more than an adjustable valve...

sabretooth · Postby **sabretooth** » Wed Apr 05, 2006 11:50 am

Matty wrote:I believe it should be, if it's not mounted in the cabin.

This agrees with what I have been told.

maxwolfie · Postby **maxwolfie** » Wed Apr 05, 2006 11:58 am

Not trying to start anything, but why would you want to do this anyways (Just out of interest)

Bevan · Postby **Bevan** » Wed Apr 05, 2006 12:02 pm

maxwolfie wrote:Not trying to start anything, but why would you want to do this anyways (Just out of interest)

Matty wrote:I have an NB prop valve on my car which made a noticeable improvement in braking.

CT · Postby CT » Wed Apr 05, 2006 12:06 pm

You can increase yor braking performance by adding more rear bias in general than factory. It has transformed my race car's braking to the point that I can adjust it mid corner so if I am locking a brake I can stop it immediately. In the wet, it even more important as you need to run much more rear bias.

If you really need to do it on a road car, I'd say it's more likely that something isn't working properly. Easier totry a retrofit as Matty suggests or different pads front to rear. I don't know that you'd need adjustability unless you have wildly altered the weight distribution or caliper piston sizes of the standard car.

Matty · Postby **Matty** » Wed Apr 05, 2006 1:13 pm

CT wrote:I don't know that you'd need adjustability unless you have wildly altered the weight distribution or caliper piston sizes of the standard car.

two reasons to choose an adjustable valve:
1) it's cheaper
2) it means you don't have to try a dozen non-adjustable valves to find the best one.

Once it's dialled in you should pretty much be able to forget about it - with the possible exception of a radical change in pad compound.

(NB: higher-mu pads front and rear will give you more rear bias, by lowering the required hydraulic pressure)

Astroboysoup · Postby **Astroboysoup** » Wed Apr 05, 2006 1:17 pm

I just ahd a quick read through the 44 page adr on brakes and it says nothing about changing brake bias.

but if you change them they have to still meet the other 6 part specifications. i would list them but each part has about 20 dot points

CT · Postby CT » Wed Apr 05, 2006 2:44 pm

Matty wrote:
CT wrote:I don't know that you'd need adjustability unless you have wildly altered the weight distribution or caliper piston sizes of the standard car.

two reasons to choose an adjustable valve:
1) it's cheaper
2) it means you don't have to try a dozen non-adjustable valves to find the best one.

Once it's dialled in you should pretty much be able to forget about it - with the possible exception of a radical change in pad compound.

(NB: higher-mu pads front and rear will give you more rear bias, by lowering the required hydraulic pressure)

Fair call - except for those reasons!!

rain902 · Postby **rain902** » Wed Apr 05, 2006 7:42 pm

for reference, wilwood adjustable valve is about $120, plus installation

tasroadster · Postby **tasroadster** » Wed Apr 05, 2006 10:22 pm

Who / Where from exactly???

Thanks.

rain902 · Postby **rain902** » Wed Apr 05, 2006 10:32 pm

tasroadster wrote:Who / Where from exactly???

Thanks.

my mechanic, maranello motors http://www.maranellomotors.com.au

got it for me and installed it - he does a lot of race prep on a lot of different cars - also services my work van - a good man.