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Old 10-22-2010, 07:35 PM
fairlane_68
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Default Stupid question re: Wilwood pedal assy

I've been getting alot of emails from race parts sites that have proportioning valves in them. So many that I'm beginning to wonder if it's a sign from Jesus or something. If I'm using the Wilwood pedal setup with the balance bar, do I need a prop valve at all? I thought using the balance bar eliminated the need for it. Wilwood's tech support is closed, so I can't call them till monday.
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Old 10-22-2010, 09:27 PM
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wre46 wre46 is offline
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Quote:
Originally Posted by fairlane_68 View Post
I've been getting alot of emails from race parts sites that have proportioning valves in them. So many that I'm beginning to wonder if it's a sign from Jesus or something. If I'm using the Wilwood pedal setup with the balance bar, do I need a prop valve at all? I thought using the balance bar eliminated the need for it. Wilwood's tech support is closed, so I can't call them till monday.
You should put in a prop valve in the "Rear" brake line that you can reach to fine tune. If you had the same size master cylinders, you wouldn't need the balance bar. It is a fine art to adjust the balance bar. Wilwood explains how to do it on there website.
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Old 10-22-2010, 09:35 PM
fastandyracing fastandyracing is offline
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Default Ditch the prop valve

Robert,

I asked the same question at PRI last year, and was told to ditch the prop valve when you go to the dual master set up with a balance bar.

I installed the dual master setup on my fox mustang about 5 or 6 races ago and love it.

I have even gotten to the point that I made a small adjustment to the bias (3 or 4 clicks) towards the end of a 30 minute race last weekend. The fuel burning off had made the car just a little squirrley under hard braking with a downshift, a couple of clicks out of the rear and it felt better.

I put a set of brake pressure gages on my dash and have found them to be very useful in getting a baseline setup. I had recently made a major rear suspension change (from torque arm to 3 link, wow what a difference), and found that I could put tons more rear brake in the car, to the point where I had maxed out the bias bar adjustment. I changed one master cylinder size by 1/8 of an inch, and used the pressure gages to reset my baseline pressures back where they had been, now I am in the middle of the range and have good adjustment on either side.

I have also made the observation that some tracks like a decidedly different front/rear bias, so the pressure gages allow you to base line a set up from track to track.

Andy
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Old 10-22-2010, 09:45 PM
fastandyracing fastandyracing is offline
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Just responding to my response, and Jeff's comments.

Jeff, I don't know if you have done this mod to your car yet, but the prop valve is pretty much a street car bandaid we all had to use when we were running street car type mastercylinders. Once you put in the bias bar and dual master cylinders, the prop valve is pretty much useless.

In any case, there are many things that could cause you to adjust your brake bias off of a true 50/50. I have the same size master cylinders, but different caliper piston sizes front and back. I have way more front weight than rear, I even have different brake pad compounds front and back, all of these things will cause you to adjust your bias bar away from a true 50/50. I even found out that fuel burn off during a 30 minute race made the car a little wierd under braking, and I took a few clicks out of the rear bias and it settled down.


And the most dramatic thing I recently did, changing from a torque arm (with way to much anti squat it turns out) to a 3 link with much less anti squat, made a HUGE difference in how much rear brake I could run and have the rear be stable under braking. I have made my third link adjustable, and if I add antisquat to improve traction (or in Nascar speak "drive off of the corners"), I find that I have to reduce rear brake pressure to compensate for the "lifting" affect antisquat has under braking.

Andy
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Old 10-25-2010, 01:12 PM
fairlane_68
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Gentlemen, thank you for your replies. I did go with the Wilwood recommended 7/8" front and 1" rear master cylinders, and so far, I like the way it feels. But that's without any baseline setup or even track time, and still on stock brakes.
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Old 10-25-2010, 02:36 PM
fastandyracing fastandyracing is offline
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FYI, I started out with the same master cylinder set up. I do have much smaller rear pistons, 4 piston 1 3/4 front, 4 piston 1 1/16 rear.

I recently switched to 1" front and rear when I did the torque arm to 3 link change, it allowed me to get back into the middle of the range on the bias bar.

If you have larger rear pistons, the 1"/7/8" combo may work just fine.

Andy
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Old 10-26-2010, 04:41 AM
fairlane_68
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I may end up changing to a 1" front after I switch to the race brakes. I'm probably going to use the Wilwood rears that use the factory E-brake. Off the top of my head I don't know what size piston those use. Once I get the tranny back in and get the hydraulic clutch parts in, I'll tinker with the brakes and see what I like.

No...I haven't got that Tremec in yet...
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Old 10-26-2010, 03:52 PM
Walther
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Quote:
Originally Posted by fairlane_68 View Post
I'm probably going to use the Wilwood rears that use the factory E-brake. Off the top of my head I don't know what size piston those use.
That is a HEAVY set-up; like 5-7 pounds more per side than their "race" set-up. You can call Wilwood and they will put together a kit for you using the new Dyna-Pro calipers. That set-up is actually cheaper than the street version with the e-brake. Food for thought.
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Old 10-26-2010, 04:18 PM
Ted Johnson Ted Johnson is offline
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Default wilwood stuff

Just fyi, for anyone needing any Wilwood product, let me know. Lots of good advice here and I can offer a few different combinations. With manual brakes you can really tailor your brake system to your own liking.

Let me know.

trj20@cox.net

P.S. Wilwood has some new material rotors that have been tested this year. They showed much improved wear characteristics to what they have offered in the past. If you are looking to purchase rotors wait until these hit the market. I will have more info soon on these.
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Old 10-26-2010, 04:28 PM
jimwheeler jimwheeler is offline
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Ted brought one of the top Willwood guys to the Runoffs. They had brakes on T1 cars, STO cars and a lot of ASedans, including my car. We tested rotors, and other cars were testing calipers, etc. They are really interested in the SCCA racing market. I see good things coming in the future.
Ted is the guy to go to. He can get you hooked up with whatever you need.
I have also told him that he is free to share any and all of my information, as to piston sizes, pad material, etc.
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