more rear brake bias
 

On my autocross car I would like to add more rear braking ability... Now I know that you must have the majority of your braking on the front, but sometimes I need more to the rear. Sometimes it seems that I am locking up the front too much while the rear NEVER locks.

Has anyone added a rear brake bias adjuster?? Is there anything you can do with the stock proportioning valve to add more rear bias???

Please advise if you have done something like this!

Without knowing your whole situation and setup, I would suggest playing with pad compounds. This is relatively cheap and won't screw anything else up. If you go with Hawk pads, for example, you can get a higher mu pad for the rear and see if that does it. If you don't like it, you can easily switch back.

As for prop valves, they're generally plumbed in line with the OEM prop valve to reduce pressure to the rear -- which is the opposite of what you want.

Hmmm... I will check into the rear pads. I am running Hawk pads front and back, but not sure which ones. Guess i would look for some that have a little more initial bite...

Hawk HP+ is where it is at. Tons of bite, makes my drum car feel like a disc car.

No way to adjust the bias that I know of unless you replace the proportioning valve with an adjustable one which might bump you into another class. Anyway, make sure your back brakes are adjusted every time you go out.

Other than that the reason the fronts start locking up more than the rears is that the rear drum brakes (I'm assuming stock drums) will heat up faster than the fronts and start fading faster. As stated you can try playing with various shoe compounds to see what you can get. Of course if its an 84 and you have discs in back then I'm out of ideas for now.

i think the prop valve chart is in the FSM, might be worth looking at. it does bleed off pressure to the rear, but maybe you can slow it down.

ive seen the stock valve made adjustable before...

Yes it is a GSL with factory LSD and disc brakes...

This is what I was hoping I could do....any ideas folks???

i'm not sure whats in there, a ball and spring or something? you just put a bolt in there to make the spring adjustable.

The PPV has a needle and a spring. Not sure what you could change other than a stiffer/softer spring. You might try going with a softer/grippier tire compound in the front, maybe lowering the air pressure.

I will be swapping soon to Hoosier A6 autocross tires... These tires will be "grippier", but I will have them both on the front and rear...

Probably the same problem, but with grippy tires...

Most of us who AutoX FB's run a more aggressive pad inthe front because of too much rear bias. You might have a sticky real caliper... Try rebuilding your calipers. It's dirty and nasty, but worth the work. I run Hawk HP+ front and regular hawks in the rear. Usually under steer from a FB menas you're going in too fast, and then not applying the throttle soon enough. I tend to go in too fast and throttle too early, so I tend to drift through a lot of turns. It's fun, but its so fugging slow....

I definitely have my hands full with understeer...I will try to change my driving habits a little by not going in so fast and quickly accelerating out of the turns. A lot of my current understeer problem is from rolling around on 6 to 7 year old Yokohama A008's (205/60/13)