dual m/c and balance bar

[GM Muscle]

ok so i have a stock 69 camaro braking system, 4 wheel power drum brakes.
i have a set of 4 wheel disc off of a 2002 trans am and the adapter plates for the fronts to bolt them up to my stock drum hub. of course i know i have to turn the drum down to fit the rotor.
My motor is not going to have enough vaccuum to run the power booster right and i dont really like the looks fo all the lines and stuff on the hydro boost setup, so im opting for a manual daul master cylinder and balance bar setup. im guessing 7/8front and 1"rear? what should i go with using the discs? im trying to keep this car budget oriented so any input would help. ive seen a few cnc setups for like 300 or so but if i can just go to smilies and pick up some wilwood m/c's im only 1 mile away. thanks in advance.

[turbo67camaro]

How big the MC's are, depends on the piston area of the calipers.

To calculate piston area, use the following equation: πr2 (3.14159 x radius squared.)

If using calipers with more than one piston, calculate the area for each piston, and then add the areas together. If the caliper has pistons on both sides of the rotor, disregard one side.

Caliper Piston Area (in2) - Master Cylinder Bore Diameter (in)
Up to 3.6 - 5/8
3.6 to 4.2 - 7/10
4.2 to 4.5 - 3/4
4.5 to 4.7 - 13/16
4.7 to 5.5 - 7/8
5.5 to 5.9 - 15/16
5.9 to 6.3 - 1
6.3 to 7.6 - max 1⅛

Often, the piston diameter is known and specified in millimeters.

Example: 45mm rear single piston calipers. So:

45mm diameter = 22.5mm radius
22.5 millimeters radius = 0.885826772 inches radius
Piston Area = 3.14159 * 0.885826772 inches * 0.885826772 inches = 2.465 in2

Thus, a 5/8" bore MC is called for in this example.

[GM Muscle]

wow. thanks man

[Apogee]

In addition to turbo67camaro's information, you'll want to consider the brake balance that you want to build into your system. Normally you would size the MC bore for the front caliper (twin 43mm in this case), then the rear and then adjust the rear bore (typically increase in order to reduce pressure) to set the baseline balance of the system. This should take your ride height, weight distribution, tires, etc into consideration as well as the range of adjustability of the balance beam setup for optimal performance, but a 65/35 or 70/30 split is fairly typical.

A balance bar system generates a linear relationship between front and rear brake pressure based on the bore sizes of the MC's. There is no "proportioning" involved unless you install a proportioing valve, adjustable or otherwise, into the rear system. The only adjustment is on the beam to shift your balance front to back or vice versa.

It's actually a bit more involved than that, so I would strongly suggest contacting Tilton and discussing your application with them as they seem to have the most helpful technical support IMHO, nothing against Wilwood or CNC Brake.

Tobin
KORE3

[GM Muscle]

Ok guys im ready to do this. Does any one recommend a specific brand of m/c and or pedal? anyone use any combination on theirs that worked out good?

[Payton King]

I am running a twin set up on my car. I use tilton masters and if you are willing to cut up your stock set up now I can give you pics of mine. the easier way is to use a tilton pedal set up as well, but you may have to alter to pedals. if you want more info let me know.

[syborg tt]

Great thread guys

[Payton King]

If you call Wilwood they will tell you to get a 7/8's for a manual system. That is correct if you are using a tandem master. It will not work with duals and a ballance bar. Been there and tried that.

You are pushing 2 masters so you will need to split the leg pressure by 2. I have run a number of calculators on this and trial and error testing...how I arrived where I am now.

I have 1 inch, 7/8, 3/4 and 5/8 masters now in my possesion. LOL

With a 6:1 to 6.2:1 ratio, you are looking at 5/8 or 3/4 on front. Size the rear one step bigger( all of this depending on your calipers. If you are using SL6's and SL4's in the rear I am right on). That will get you close on the bias and use the ballance bar to tune from there.

My piston size is 1.62, 1.12, 1.12 on the front and 1.75, 1.75 on the rear with 13 inch rotors.

[GM Muscle]

thanks man. great pics. im just using the pbr calipers in the front and the factory late gm rears. ill pull down my factory pedal and stuff when i get the chance and see if i cant get it all mocked up. once again thanks for the pics and info

how far down would you say you had to move it? just guessing?

and do you have anyway that i could contact jim p?

[Payton King]

Caliper.

The distance he moved the clutch down had to do with getting a straight shot at the masters so the master push rod was not moving at an angle and loosing mechanical advatage. On mine it is about 1 to 1.5, I did not measure but it is close.

You never said if you were running a stock type clutch, hydrolic or if you car was an automatic. Anyway I am sure Jim would be happy to get you set up but I still think if I had it to do over I would get the Tilton pedals to work

Take a look here: http://www.tiltonracing.com/content....list2&id=4&m=b

I think it would be far easier to do this than the route I took. Take a look at the drawings as it has measurements. You will need to cut holes in your firewall, but you will need to do that anyway. If you do this you will need to remove the stock brace/pedal locator and fab up something else.

If you like mine I will get you Jim's number