power vs manual

[70staged]

What is the stopping distance, and other difference between 4 wheel manual disc brakes and 4 wheel power disc brakes. I am thinking about going with Right Stuff Detailing for the 4 wheel disc brakes for my 70 Skylark. I am wanting to keep my 15 inch taxi cab steel rims is the reason I am not going with bigger brakes.

[Classic Nova & Performance]

Pedal effort is the main difference. The only difference in the system is the power booster/master cylinder. Brake components are identical.

[Apogee]

Assuming you can achieve lockup with either manual or power brakes, and thus threshold braking, your stopping distances should be the same since that's a function of your tires. As Walt pointed out, the difference between power and manual brakes is the amount of pedal effort required for a given brake torque.

Tobin
KORE3

[70staged]

ok because I have 4 wheel manual drum brakes now

[71RS/SS396]

Sizing of the master cylinder is really critical with manual brakes.

[Apogee]

ok because I have 4 wheel manual drum brakes now

While 4-wheel manual drum brakes can be made to perform adequately under light use, they'll never be great. When they're not serviced properly, worn out or have otherwise been neglected for extended periods of time, they only get worse. That said, the rear drums make excellent parking brakes, so if you're sticking with 15" wheels and on a budget, I would upgrade the fronts to disc and leave the rears as drums myself. You have some options with respect to front disc kits, however the OE type D52 caliper kits will be the most cost effective. If you want to spend more, you have some Wilwood Dynalite and Dynapro kits available that could fit.

Tobin
KORE3

[MCMLXIX]

Not to hijack this too much, but I have a 69 Camaro all drum car that I plan on a LS1 Camaro front disc swap and keep the rear drums. I want to keep it manual but upgrade to a Wilwood tandem MC. I can't find the distro block, so I need a recomendation on the MC bore size (7/8” , 15/16", 1.00” and 1.125”), distro block and if I need a residual 2# / 10# valve somewhere?

[Apogee]

Not to hijack this too much, but I have a 69 Camaro all drum car that I plan on a LS1 Camaro front disc swap and keep the rear drums. I want to keep it manual but upgrade to a Wilwood tandem MC. I can't find the distro block, so I need a recomendation on the MC bore size (7/8” , 15/16", 1.00” and 1.125”), distro block and if I need a residual 2# / 10# valve somewhere?

We would generally run a 7/8" to 15/16" bore master cylinder with a manual LS1 brake setup, noting that the larger bore master cylinder will produce a pedal that is about 12% higher than the 7/8" unit but require 12% more pedal effort to achieve the same output pressures. Wilwood makes a nice all-in-one distribution block with built-in adjustable proportioning valve (#260-13190 (http://www.wilwood.com/MasterCylinders/MasterCylinderProd.aspx?itemno=260-13190)) that will bolt right up to their tandem master cylinder, or you can buy the master cylinders now complete with the same valve and bracket assembly under one part number as well.

As for residual pressure valves (RPVs), you shouldn't need any. The 10 psi RPVs are intended to be used with drum brakes in order to maintain pressure on the cup seals in the wheel cylinders and keep them inflated when the shoe retraction spring collapses everything when you release the brakes, whereas the 2 psi RPVs are intended for disc brake circuits where the master cylinder is mounted level or below the calipers so as to prevent flowback from the calipers to the MC.

Tobin
KORE3

[MCMLXIX]

Not to hijack this too much, but I have a 69 Camaro all drum car that I plan on a LS1 Camaro front disc swap and keep the rear drums. I want to keep it manual but upgrade to a Wilwood tandem MC. I can't find the distro block, so I need a recomendation on the MC bore size (7/8” , 15/16", 1.00” and 1.125”), distro block and if I need a residual 2# / 10# valve somewhere?



As for residual pressure valves (RPVs), you shouldn't need any. The 10 psi RPVs are intended to be used with drum brakes in order to maintain pressure on the cup seals in the wheel cylinders and keep them inflated when the shoe retraction spring collapses everything when you release the brakes, whereas the 2 psi RPVs are intended for disc brake circuits where the master cylinder is mounted level or below the calipers so as to prevent flowback from the calipers to the MC.

Tobin
KORE3

But I was going to keep the factory rear drum brakes for now, so I would need a 10# RPV after the adjustable proportioning valve...... (PS: I used the same part #260-13190 on the 72 Blazer)

[Apogee]

But I was going to keep the factory rear drum brakes for now, so I would need a 10# RPV after the adjustable proportioning valve...... (PS: I used the same part #260-13190 on the 72 Blazer)

Yes, to be technically correct, you'll want the 10 psi RPV then in the rear circuit...and it doesn't matter where you put it relative to the APV. In fact, you can put as many 10 psi RPV's as you like into the circuit and they will still only maintain 10 psi residual pressure in the circuit as they're not cumulative.

Tobin
KORE3