Prop Valves

[Track Junkie]

I have the old Brembo BBK which requires proportioning valves since it uses the same calipers at all 4 corners. Has anyone found any prop valves out there OTHER than Tilton's that work well for this setup and are well matched, left to right?

OR, is there a valve setup out there that COMBINES the two rear lines into one so the left to right pressure differential is not an issue?

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[ScienceofSpeed]

The rear lines are split on the NSX since each channel is independent. I do not think it would be easy to use one valve for each line due to this. Any well made proportioning valve should result in equal balance to the left and right rear corner.

We're currently having several units made, if you are interested.

Cheers,
-- Chris

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[email protected]
http://www.ScienceofSpeed.com

 

[Track Junkie]

Who makes them and what style are they? Lever, Screw type, other?

Thanks.

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[ScienceofSpeed]

They use Tilton metered lever-type valves. Contact me if you're interested. The manufacture wishes to be nameless

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[email protected]
http://www.ScienceofSpeed.com

 

[Andrie Hartanto]

I have to chime in on this one.

I had experience with 4 pairs of tilton lever type proportioning valve. And there is no way you can have a matched set left and right. Even Tilton finally agree to this. The only solution is to get the screw type, so you can fine adjust them. The preset adjustment is not consistent enough.

The only way you can combine the rear line into one is to yank the ABS out. NSX uses 4 channel ABS system.

Pricate me if you have any questions.

 

[Michigan NSX]

Originally posted by Andrie Hartanto:
...Pricate me if you have any questions.

I didn't think that kind of talk was tolerated on this forum!

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'91 Black/Black

 

[Yellow Rose]

Andrie is correct. I had a good telecon with Tilton about this many months ago. If you take two lever-adjusted prop valves side-by-side with the same setting position, the amount of bias is not exactly the same.

After fiddling with a set of prop valves and the pre-bent lines, I gave up. The two valves and four lines are in my tool box, collecting dust.

I achieve F-R brake bias with different pad compounds with excellent results.

 

[Track Junkie]

And those pads are??? Do you have the Brembos too?

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[Yellow Rose]

Brembo 13" drilled rotors with the Lotus caliper at all four corners. Front pads are Carbotech Panther Plus. Rear pads are Porterfield R4-S.

At the track, Carbotech dusts more than Porterfield. On the street, the Carbotech will squeal when the rotors are at some intermediate temperature. I have a laser pyrometer, but have never bothered to shoot the rotors. They only squeal during the last five or ten feet, when coming to a stop. The noise doesn't bother me at all, because when I depress the center pedal, my NSX stops like there is devine intervention. Sidebar - a couple of months ago, I was coming to a stop in traffic next to a Porsche (read - Brembo derivative brakes are standard issue with those cars.) He had his windows down, so he couldn't ignore the noise. He looked over at my front brakes with this "what-kind-of-crap-brakes-are-on-that-car?" expression on his face. When he saw what was lurking behind the Technos, he gave me a thumbs up.

 

[ScienceofSpeed]

Andrie --

Maybe you received a bad batch? On the Brembo GT setup I did, the Tilton proportioning valves we installed worked really well, although, I felt that the pedal feedback was not as good. Perhaps the only way to detect the minute differences is on the track under thresh-hold braking?

This why I prefer balanced brake kits out of the box, no need to mess with prop valves.

-- Chris

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[email protected]
http://www.ScienceofSpeed.com

 

[Andrie Hartanto]

Have you tested them on the track? Have you tested them with the pressure gauge?

I went through 3 pair and Dan's 1 pair, that's 8 total proportioning valve. Each pair bought at different time. None of the 3 pairs I had (6 total) matched. Dan's pair didn't matched either. Even Tilton say that it is impossible to get them matched. Now I'm playing with the screw type. So far so good, but I'll let you know when I get more info.