Adjusting proportioning valve? - Lateral-g Forums

**WSSix** · #1 06-22-2013, 01:06 PM

Is there a proper method for adjusting the proportioning valve or is it really just a matter of feel and or preference? So far with what little I have driven the car and done brake checks, I like the way it stops. I really have nothing to compare it to though. My factory 79 brakes were crap and a C5/6 is much lighter than my car. Really, I'm just slamming on the brakes and going whoa that felt good, lol.

The car has C5/6 front brakes and C5 rears. The front system is from Tobin at Kore3. I'm using my factory 4th gen master cylinder and factory 79 booster.

I have only really laid into it a couple times but have not locked up the tires at all. I have Sumitomo HTRZ tires. I have no idea if I should be able to lock up the tires. I would think so though. I'm simply using that as a metric for braking power even though locking up is not a good thing.

I do have access to a infrared thermometer if that would help. Any advice is appreciated.

Thanks

**andrewb70** · #2 06-22-2013, 08:38 PM

The front brakes should lock up before the rear brakes. If the brakes aren't locking up at all, I suspect that you're not generating enough pressure at the calipers.

Andrew

**WSSix** · #3 06-22-2013, 08:40 PM

I'll try again to lock them up tomorrow maybe. I wasn't really trying earlier. I was just laying into them.

Is there really anything more to it than making sure the rears don't lock up first?

Thanks, Andrew.

Vegas69 · #4 06-22-2013, 09:14 PM

Go out and get the brakes good an hot and make some stops from freeway speeds. (I'd make a couple practice stops first) This should be done at threshold braking. Meaning, you are on the brink of lock up but modulating. When the ass end is starting to come around, you have to much back brake. Depending on pad compound, you may not have enough rear brake for it to be an issue. Meaning, you can have all the rear brake in the car.

Track Junky · #5 06-22-2013, 09:18 PM

I made my adjustments at the track. My initial setting had the rears skidding a bit as I was aproaching a corner hard on the brakes. I backed it off a little at a time so that I could get maximum rear braking without a skid potentially helping the fronts from taking most the load.

**WSSix** · #6 06-23-2013, 05:21 AM

Ok, makes sense. I'll get out there and play some more soon. Thanks