bias valve

[Bazda]

I would just change rear pads to different compounds for the desired grip that you need.
So much hastle to install a bias valve into a FWD, especially the way the M/C works as well.

[matt dunn]

I've been through about 5 sets of front pads and still on the same set of std toyota back pads in factory callipers, they are about 1/4 - 1/2 worn,

the rears are hardly touched.

My car has similar problems withn brakes.
With good pads in the rear the bias doesn't remove enough rear and I just run crap pads.
Only downside is that it really chews thru the rears,
at least one, possibly two sets fo rear pads in a weekend,
and not just worn a bit, down to the backing plate.

[fxgt race]

At this stage the factory valve has been scraped,Ive conected the front brakes with a joiner were the valve used to be, so now the fronts are separate to the backs. Ive used a tee to join the rears together,run a line from the masters second port to the bias valve inside the cabin and out to the tee to the back brakes.

will have to test at puke before heading down to taupo for our first round to see ive the valve reduces the pressure enough,if not i will put another after market reducer valve in line.

the pads in the wilwoods are about the size of a match box but the calipers being 2 pot sure do work well, it saved 9.2 kgs in weight fitting these and removing the hand brake.

[Bazda]

Just go for a drive down the road quickly and see if it locks the rears.
Must be some back roads you can do a few tests on.

[neo]

For reference, both cars Ive used a adjustable proportioning valve in have had split front / rear systems.

For both I removed the factory bias adjuster/valve and ran the fronts directly off the master cylinder and the rears via the prop. valve. Never had any issues apart from the 3 laps I did with no meat left on the front pads

[MAGN1T]

Most sensible fix is to put the factory brakes back on the rear. The rears hardly do anything anyway.
Pretty pointless upgrading the rears, finding out that they lock up (as expected) then having to mod it more to overcome the initial cockup.
BTW been there done that with an upgrade. My fix was a single circuit system, remote booster only boosting the front. It wouldn't be legal these days though. That was big drums on the back too.

Steve

[Guss]

Pretty pointless upgrading the rears,
Steve

don't think so

it saved 9.2 kgs in weight fitting these

[IH8TEC]

Pretty pointless upgrading the rears,
Steve

don't think so

it saved 9.2 kgs in weight fitting these

i'd rather have a car that doesn't lock up the rears around a race track and have have the extra 9.2kg.

[matt dunn]

As weird as it sounds, i am going to fit larger rear brakes to my car to prevent the rears locking,

as from the brake experts i'll talked too have said it will fix/help it.

Same way smaller puck clutches have more grip due to the same pressure on smaller surface area,

same pressure on a larger surface area gives less.

Going to test the theroy when I get a chance to suss out some discs and stuff that will be close enough to make fit.

[fxgt race]

Pointless i don't think so,9.2 kgs is alot.Its a race car,weight is everything,when you have a race car you will understand.the valve is in and will see how it goes.Neo i think u understand,cheers. Power to weight is the key, as our class weight is 720kg with driver, my car still weights 770, Im looking for everything.

[MAGN1T]

You could always throw a sack of cement in the boot to give it some ballast to stop it from locking up .
Totally pointless if you can't slow down without getting it sideways and having to lift off the brake pedal.
There's other ways too though. Bigger tyres on the back or taller tyres on the back.
Anyway, brakes, when you make them better you actually increase the weight transfer from rear to fromt so the rears do less and less.
Hey you could remove them altogether?

Steve

[Dunny]

What pad compounds are you running?

[allencr]

It might help if you stopped trying to call it a proportion or bias valve because it isn't & does nothing of the sort even though they are popular names for it, it's only a valve that limits pressure to the rears.

[TRD Man]

Difficult to know where you're coming from here allencr. The std item on the bulkhead is very much a proportioning valve. It takes fluid in at a certain pressure and proportions that at differing pressures front & rear.

You are correct in respect of the adjustable item but as Wilwood themselves market the product as a proportioning valve it makes good sense, and is only natural, to refer to it as such.

Either way I think we all understand what is being spoken about and from his postings fxgt race is on the right track with what he is doing.