Posted 28 August 2011 - 08:56 PM
TsTKl, on 28 August 2011 - 01:49 AM, said:
I was under the impression that the more simple proportioning valves just "turned down" your rear braking force by restricting flow to the rear. If your problem is too much front braking force you wouldn't be able to adjust it rearword at all. It depends on your set up though. I guess technically you could put one on both the front and the rear and then reduce pressure to the front. Either way though, your adjusting your brake bias at the cost of increasing pedal effort. I like the idea of a bias bar better because your mechanically changing the force going into each individual master cylinder. With a stock style master cylinder your line pressure will be the same in both lines unless you restrict flow in one.
The proportioning valve basically allows equal pressure front to rear up to a certain pressure before pressure to the rear is reduced at a linear rate. Under low braking where little weight transfer occurs, this is better than a bias bar where the braking force is linear and only set to provide the correct brake bias at full braking. For example, just to throw numbers around, a proportioning valve could distribute 60/40% braking at 20% power while a bias bar may be 70/30. Meanwhile at full braking, the proportioning valve could be set to meet 70/30 braking and be equal with the bias bar.
What this boils down to is that at moderate braking, a bias bar is actually giving too much front bias. You'd likely never see a problem on the race track, but on the street it can help reduce wear and tear on the front brakes and maybe make a difference in low traction situations.
JamesR, on 28 August 2011 - 01:34 PM, said:
I think wilwoods are available in different widths depending on part numbers. It's been awhile since I've looked at the catalog. I could be wrong though.
They are, but I've got these 1.25" bore calipers sitting around and making spacers is much cheaper than buying another pair of calipers.
Edited by Maxzillian, 28 August 2011 - 08:57 PM.
What's the fun in making something simple?
'87 TSI - StarOrion braided brake lines, StarOrion radiator, StarOrion alternator, StarOrion 2.5" stainless exhaust w/Magnaflow muffler, 1G MAS, Competition Clutch 15 lb flywheel, Competition Clutch Stage 4 clutch, Mookeh polyurethane bushings, ABS elimination, 8:1 Wiseco Pistons, TD05 14G turbocharger, Axiss ceramic rear brake pages, Hawk HP+ front pads, heat wrapped and ported exhaust manifold/turbine housing, Accusump oil accumulator, remote oil filter, NJV head, EVO intercooler, remote battery, D2 coil over struts, flatty front struts and control arms, 8" non-SHP wheels all four corners, 12.75"x1.25" front rotors with 4 pot Wilwood calipers, manual brakes using dual master cylinders and balance bar, gutted (deleted) brake proportioning valve and modified steering pump speed sensitive valve.