No proportion valve

[thezguy]

I destroyed my Proportioning valve when I was pulling out my motor awhile back. I need to drive the car to get an alignment on Saturday and there is no chance of getting a new one in time. What kind of a difference will I see if I bypass it? I don't knkw that I ever had it set correctly to begin with.

 

1" willwood MC

Mustang gt rear calipers and rotors

S12w front calipers

Edited October 30, 2014 by thezguy

[RPMS]

I shouldn't think you'd have problems. If it was a left-right balance issue I'd advise against it, but with a front-back setup like you're running, there should be no issue.

[thezguy]

I'd like to make note that this is a high hp street car, not a track car.

[johnc]

You're fine if you drive easy on the street to the alignment shop.  You should replace the prop valve ASAP after that and properly set it.  One rainy day and a panic stop could destroy your car and yourself.

[thezguy]

You're fine if you drive easy on the street to the alignment shop. You should replace the prop valve ASAP after that and properly set it. One rainy day and a panic stop could destroy your car and yourself.

 

I was able to borrow one from a friend. John what would you recommend the split percentage be with my particular combination of brake components.

Edited October 30, 2014 by thezguy

[TimZ]

I was able to borrow one from a friend. John what would you recommend the split percentage be with my particular combination of brake components.

The correct split is going to be the one that gives decent braking without locking the rears first.  Just start with next to nothing for brake pressure at the rear, then work your way up until you start seeing the rears lock up at the same time or before the fronts on hard braking.  Then back off a bit from there.  Then recheck on wet pavement.  You always want the fronts to lock first on a street car.

 

A few years back I had been checking something on my rear brakes and had turned the prop valve all the way up and forgot to set it back.  Just a few blocks from my house I came upon a red light and had to stop abruptly. I then had to sit through the rest of the light cycle with my car completely sideways in the lane. Not a little sideways - COMPLETELY 90 degrees sideways.  Really embarrassing but lucky that nothing worse than that happened.  Won't make that mistake again.  

[thezguy]

The correct split is going to be the one that gives decent braking without locking the rears first. Just start with next to nothing for brake pressure at the rear, then work your way up until you start seeing the rears lock up at the same time or before the fronts on hard braking. Then back off a bit from there. Then recheck on wet pavement. You always want the fronts to lock first on a street car.

 

A few years back I had been checking something on my rear brakes and had turned the prop valve all the way up and forgot to set it back. Just a few blocks from my house I came upon a red light and had to stop abruptly. I then had to sit through the rest of the light cycle with my car completely sideways in the lane. Not a little sideways - COMPLETELY 90 degrees sideways. Really embarrassing but lucky that nothing worse than that happened. Won't make that mistake again.

This made me laugh! I understand, thanks!

[Leon]

If you want to set it and forget it, set your bias at the highest grip condition. No need to check it in the wet unless you're dialing in different biases in the wet and dry. The reason for setting your bias at the highest grip condition is because with grip comes weight transfer. The more weight that is transferred to the front, the more front brake bias you need. Once you've set it, your fronts will 100% for sure lock up first in the rain because your bias is dialed in for maximum front weight transfer.

 

Proportioning doesn't affect light braking (the front and rear circuits receive the same amount of pressure up to a certain pressure) so a quiet trip to the alignment shop will do no harm, unless you need to make a panic stop of course...

[thezguy]

If you want to set it and forget it, set your bias at the highest grip condition. No need to check it in the wet unless you're dialing in different biases in the wet and dry. The reason for setting your bias at the highest grip condition is because with grip comes weight transfer. The more weight that is transferred to the front, the more front brake bias you need. Once you've set it, your fronts will 100% for sure lock up first in the rain because your bias is dialed in for maximum front weight transfer.

 

Proportioning doesn't affect light braking (the front and rear circuits receive the same amount of pressure up to a certain pressure) so a quiet trip to the alignment shop will do no harm, unless you need to make a panic stop of course...

Yeah makes sense. I was able to make some new lines and get the valve plumbed in. Thanks for the help.