Hey all,

Came across an adjustable brake bias valve in my boxes o' stuff. It's the lever type adjusting valve, with something like 7 positions. Anyone have any experiences with it? How about installation? It looks like it might need some brake line fabrication needed. Is it even worth trying?

Thoughts? Suggestions?

-Josh2

Josh...
definitely worth it.
do you still have the stock bias valve?
can you put it in place of said valve?
usually the easiest placement.

Mine is in the cockpit, but really isn't necessary.
my old one was in the bias valve location.
I did try the "T" but ended up going back to an adjustable valve. (because I needed it!)
BIG difference !

tune it in on a dirt road
if you need adapter fittings, James Adams: JWest has sold me some in the past.

brant

Ask Chris Foley (aka CFR Welding, Tangerine Racing) about these. I think he uses them on his race car(s). -Mike

QUOTE (brant @ Dec 21 2005, 03:28 PM)

tune it in on a dirt road

I would suggest tuning it on concrete--the grippiest surface you can find! You want to set it up for a worst-case, which is having the most weight transferring to the front wheels. That means sticky tires and a grippy surface. Set it so the rears are just shy of lock-up when you lock the fronts. (Ugh, sounds like a good way to flat-spot a set of stickies!!)

--DD

I put one with the adjustable knob in the stock location. Had to fab a mount and a couple of brake lines, but it wasn't bad. Much better than the stock mushy valve.

I realize that if you are not reworking the entire brake system, then placing the adjustable valve in the same location as the stock one makes sense.

However, I am restoring a 914 from scratch and will be redoing all of the brake lines, how 'bout placing it under the dash, just to make it easier to get to and adjust?

Reasonable idea?

QUOTE (db9146 @ Dec 21 2005, 08:29 PM)

I realize that if you are not reworking the entire brake system, then placing the adjustable valve in the same location as the stock one makes sense. However, I am restoring a 914 from scratch and will be redoing all of the brake lines, how 'bout placing it under the dash, just to make it easier to get to and adjust? Reasonable idea?

center tunnel if it needs to be inside. tap into the hard brake line in the tunnel. easiest way me thinks....
and once its set....how often do ya need to adjust it????? so id vote for OE location (engine bay) or center tunnel....

AA

Where on the center tunnel if I'm running a full console? What did you have in mind?

QUOTE (db9146 @ Dec 21 2005, 08:36 PM)

Where on the center tunnel if I'm running a full console? What did you have in mind?

is this a racecar or a street car?

streetcar... engine bay.
racecar (if class allows a bias adjuster inside) then id tap into the tunnel line at the rear acces plate and put it at the very back. out of the way....

AA

I agree with the above comments.
under the dash doesn't really work, because the brake lines are not there.
Many classes won't allow adjustable and won't allow in cockpit.
only heavyily modified classes usually.

even as a race car I only adjusted during a race 1 time the entire last season.
and that was a 2 hour enduro where I had burned 45 minutes worth of gas and wanted to play with the adjustment.

I found myself tuning it to optimum, and after finishing the race I checked the final setting. It was withing a hairs width of my starting adjustment.

what I'm saying is that you will not be playing with this after its initially set.
I ran the knob in the engine bay on my old race car for 10 years
its a set and forget kind of item.
you adjust driving style to compensate for traction, weather, temperature, track conditions more than you do the brake bias.

if you really want it in the cockpit then... (as stated above) the rear of the center tunnel is the only convienient location:

Brant - why isnt that bracket drilled for lightness?

QUOTE (Aaron Cox @ Dec 21 2005, 11:24 PM)

Brant - why isnt that bracket drilled for lightness?

Aaron,

I bought one of the smallest size valves I could so as to save weight.
I hated using the adapters because they are brass and heavy (but couldn't get the right flaring tool to avoid it)

I used an aluminum bracket (actually crappy door stop corner molding stuff) that was extremely light weight guage.

I used an aluminum bolt and nut to hold the valve....


dang... I'll drill it this winter.
(I plan on some real interesting drilling that you'll see in a later thread, and hopefully will net me 5-7 lbs)

brant

QUOTE (brant @ Dec 21 2005, 11:28 PM)

QUOTE (Aaron Cox @ Dec 21 2005, 11:24 PM) Brant - why isnt that bracket drilled for lightness? Aaron, I bought one of the smallest size valves I could so as to save weight. I hated using the adapters because they are brass and heavy (but couldn't get the right flaring tool to avoid it) I used an aluminum bracket (actually crappy door stop corner molding stuff) that was extremely light weight guage. I used an aluminum bolt and nut to hold the valve.... dang... I'll drill it this winter. (I plan on some real interesting drilling that you'll see in a later thread, and hopefully will net me 5-7 lbs) brant

atta boy

QUOTE (Aaron Cox @ Dec 21 2005, 07:34 PM)

QUOTE (db9146 @ Dec 21 2005, 08:29 PM) I realize that if you are not reworking the entire brake system, then placing the adjustable valve in the same location as the stock one makes sense.   However, I am restoring a 914 from scratch and will be redoing all of the brake lines, how 'bout placing it under the dash, just to make it easier to get to and adjust?   Reasonable idea? center tunnel if it needs to be inside. tap into the hard brake line in the tunnel. easiest way me thinks.... and once its set....how often do ya need to adjust it????? so id vote for OE location (engine bay) or center tunnel.... AA

I to installed a lever action bias valve.

I re-did all the brake lines anyway during my resto so I figured WTH,put it where it can be right at my right hand.



Ron


A couple shots

Nudder 1.


Ron

Can you open the adjustable valves all the way for bleeding the rear brakes, then adjust bake for road use?

I installed mine at the rear panel of the tunnel, similar to what Brant did. There is a union fitting there in the brake line, so you don't have to install new fittings. I attached flex line to the existing fittings and mounted the bias valve on top of the tunnel instead of in it. Since my car is a track car I didn't care about looks, but I don't see much reason to have an adjustable valve on a street car.

Okay, so to refine my question...

With the lever type valve:

Do you find that it can hold its position well? Or does it rattle loose with a stiffly suspended car? If I wanted to just replace the stock prop valve with this unit, do I need to fabricate any special fittings or lines?

Thanks,

-Josh2

I've seen lever valves used in stock locations.
I think ginter's car has one there.

I know I've seen other PCA cars with lever valves there.

It should hold, but if for some reason is loose it shouldn't be that hard to rig a way of locking it either.

special fittings depends upon the flare type that your valve accepts.
you may need an adapter fitting on inlet/outlet to go from the valves US style to the german bubble style.

the picture of mine shows these simple fittings, and James of rennshifter fame sells them (resource section will have a link to his site. Good service, good guy)

QUOTE (Dave_Darling @ Dec 21 2005, 06:21 PM)

QUOTE (brant @ Dec 21 2005, 03:28 PM) tune it in on a dirt road I would suggest tuning it on concrete--the grippiest surface you can find! You want to set it up for a worst-case, which is having the most weight transferring to the front wheels. That means sticky tires and a grippy surface. Set it so the rears are just shy of lock-up when you lock the fronts. (Ugh, sounds like a good way to flat-spot a set of stickies!!) --DD

That's EXACTLY what I was going to say. If you tune the bias on a loose surface then you'll be locking the rears first when you get to a high-traction surface.
-Ben M.

QUOTE (airsix @ Dec 22 2005, 11:29 AM)

QUOTE (Dave_Darling @ Dec 21 2005, 06:21 PM) QUOTE (brant @ Dec 21 2005, 03:28 PM) tune it in on a dirt road I would suggest tuning it on concrete--the grippiest surface you can find! You want to set it up for a worst-case, which is having the most weight transferring to the front wheels. That means sticky tires and a grippy surface. Set it so the rears are just shy of lock-up when you lock the fronts. (Ugh, sounds like a good way to flat-spot a set of stickies!!) --DD That's EXACTLY what I was going to say. If you tune the bias on a loose surface then you'll be locking the rears first when you get to a high-traction surface. -Ben M.

All right...
let me clarify my statement.
When FIRST starting out and trying to get a rough estimate I still recommend tuning on a dirt road.

I did it by having a 2nd party stand outside the car and making slow passes in a straight line at only 15 to 20mph
I did it by making sure that I was not getting rear lock up first.

Then after getting my rough settings, I moved to the race track and did fine tuning.

I understand the concern about weight transfer.
but I really didn't want to test my rough settings at 80miles per hour.

Once on the old race car I had things set a little too close and actually had just changed race pads which upset the balance. I was on the back straight at 2nd creek in 4th gear at over 100mph when the rears locked up first. I went off the track and down into a good sized drop off at 80mph BACKWARDS!

(luckily I only tore off the brake ducts, and didn't damage anything else except my pride) Really created a lack of trust on my part in the braking zone of that straightaway for the entire rest of the weekend.

This is why I advised tuning on a dirt road at a SLOW speed. Yes there is overall less weight transfer, but there is overall less grip on all 4 wheels too. you won't be able to fine tune the set up, but you can get it roughly set at alot safer speed

brant

I jsut talked with a frined of mine who said that the lever type valve (Tilton) has a very narrow range of adjustment, and that at full open already yields a 50% pressure reduction, and full closed goes up to only 75 % reduction. Seems like a bogus design...

Anyone else with direct experience with these Tilton valves?

QUOTE (jhadler @ Dec 22 2005, 04:51 PM)

I jsut talked with a frined of mine who said that the lever type valve (Tilton) has a very narrow range of adjustment, and that at full open already yields a 50% pressure reduction, and full closed goes up to only 75 % reduction. Seems like a bogus design... Anyone else with direct experience with these Tilton valves?

Here is the Tilton chart: