Wilwood Complete Adjustable Brake Proportioning Kit
12-05-2008, 09:58 PM
#41
Junior Member
Join Date: Apr 2008
Posts: 349
Total Cats: -2
Keith is right. What I add below is less important than any of the points he made.
In both lateral and longitudinal weight transfer, there is actually a slight increase with greater dive or roll angle, due to the CG of the vehicle shifting relative to the pitch or roll center. But it's typically a small fraction of a percent and can safely be ignored in any internet arguments about setup.
Before dive has occurred, the car can't transfer weight through the springs, because they are position-sensitive devices. Low-speed compression (and bump) valving can affect the rate at which weight is transferred, because they are speed-sensitive devices and can move the force on the contact patches before the car has been able to reach the steady-state compression of the springs for the decel level it will ultimately achieve. I have seen instances of excess rebound damping on the rear causing the car to get really loose on braking. Dialing out the rebound made everything peachy.
BTW, Keith, any chance you could reproduce the data on your site regarding Miata prop valves for a range of settings on the Wilwood valve? I've been looking for that for years, and even friends at Wilwood have failed to provide it. Assuming the spring is linear, all you'd really need to completely characterize the valve is the knee point at the minimum and maximum settings, and the post-knee point slope. Multiple readings around the knee point to be sure hysteresis is accounted for would be a nice bonus.
In both lateral and longitudinal weight transfer, there is actually a slight increase with greater dive or roll angle, due to the CG of the vehicle shifting relative to the pitch or roll center. But it's typically a small fraction of a percent and can safely be ignored in any internet arguments about setup.
Before dive has occurred, the car can't transfer weight through the springs, because they are position-sensitive devices. Low-speed compression (and bump) valving can affect the rate at which weight is transferred, because they are speed-sensitive devices and can move the force on the contact patches before the car has been able to reach the steady-state compression of the springs for the decel level it will ultimately achieve. I have seen instances of excess rebound damping on the rear causing the car to get really loose on braking. Dialing out the rebound made everything peachy.
BTW, Keith, any chance you could reproduce the data on your site regarding Miata prop valves for a range of settings on the Wilwood valve? I've been looking for that for years, and even friends at Wilwood have failed to provide it. Assuming the spring is linear, all you'd really need to completely characterize the valve is the knee point at the minimum and maximum settings, and the post-knee point slope. Multiple readings around the knee point to be sure hysteresis is accounted for would be a nice bonus.
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12-06-2008, 01:04 AM
#42
The data on the stock valves was not obtained by testing, but by research. They're printed in the factory manuals 
I don't have a test setup at hand that will give me the knee points of a valve.
However, Wilwood claims that their valve adjusts from 57% to 100%. When you adjust it, you're basically just moving the knee point. So from this we should be able to deduce that at wide open (100%), there is no knee point. At full close, the knee point is essentially at the origin so you have the post-knee slope of 57%.
I don't have a test setup at hand that will give me the knee points of a valve.However, Wilwood claims that their valve adjusts from 57% to 100%. When you adjust it, you're basically just moving the knee point. So from this we should be able to deduce that at wide open (100%), there is no knee point. At full close, the knee point is essentially at the origin so you have the post-knee slope of 57%.
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12-06-2008, 03:43 PM
#43
Cpt. Slow
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Join Date: Oct 2005
Location: Oregon City, OR
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Hustler if you don't want wait for FM to put a kit together (unless they already have?) I'll let you borrow my flaring tool. just pay postage from 97045, its probably about 3-4lbs.
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12-06-2008, 06:06 PM
#44
Actually, flaring tools are the sort of thing you can rent/borrow from local auto parts stores, usually for free. However, I've found that you usually get your moneys worth. It's important to prep the line well (a nice square cut, preferably with a pipe cutter and knock the edges down), but at least two of those cheap tools have broken in half on me. I only own three Snap-On tools, but my flaring tool was the first one I bought. In case you're wondering, the other two are some flare nut wrenches (cheap ones will expand and slip under pressure) and a ratcheting crimping tool...
When I think about it, the "kit" would simply be two metric unions and the two metric-NPT adapters. So basically our Wilwood kit plus one extra union. You can buy the piece of metric brake line you'd need from your local auto parts store in a length that suits you. So we've had the "kit" available for months and months
When I think about it, the "kit" would simply be two metric unions and the two metric-NPT adapters. So basically our Wilwood kit plus one extra union. You can buy the piece of metric brake line you'd need from your local auto parts store in a length that suits you. So we've had the "kit" available for months and months
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12-07-2008, 08:10 PM
#45
Cpt. Slow
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Join Date: Oct 2005
Location: Oregon City, OR
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I'm waiting on my speed bleeders to see how my standard/metric mix of lines even seals. I didn't have a pipe cutter either, so hopefully I can cut as straight as my eyes say I can.
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12-18-2008, 11:20 AM
#55
Senior Member
iTrader: (4)
Join Date: Jan 2008
Location: Falls Church, VA
Posts: 1,361
Total Cats: 17
Here's the list as I see it:
cjernigan
Rafa
Oscar
DragonsMaw (retracted?)
UrbanSoot
ray_sir_6
ScottFW
levnubhin
Hustler
leatherface24
That's 10 if DragonsMaw is in, but it looked like he was on the fence.
Come on y'all.
cjernigan
Rafa
Oscar
DragonsMaw (retracted?)
UrbanSoot
ray_sir_6
ScottFW
levnubhin
Hustler
leatherface24
That's 10 if DragonsMaw is in, but it looked like he was on the fence.
Come on y'all.
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12-26-2008, 11:58 PM
#57
Tour de Franzia
iTrader: (6)
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,085
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so do I need to call them again or are we still waiting? I have a track day in 2-weeks. I'd like to get my **** together so I can rape and spit on rich people.
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