Brake Booster & Master Cylinder Recommendations

[magoo426]

Hi guys.

I have purchased 11" front and rear disc brake kit from Wilwood, with 4 piston calipers.

I was wondering what type of master cylinder and brake booster do you guys recommend for this application.  It's going onto a 72 challenger. Looking to use 17" rims.

Thanks!!!

[Denison636]

I would recommend calling Willwood, no one knows better then a manufacturer when it comes to there own set up.

[Chryco Psycho]

I fyou have Power steering & are running much of a cam I would suggest hydro boost as it will work better than vacuum assist

[magoo426]

So i called Willwood yesterday asking what brake booster and master cylinder they recommend with the front and rear disc 4-piston caliper and disc brake setup that i have. They asked what vacuum will i be pulling. I have no idea what i will be pulling. The cam im running is a comp cam, xtreme energy, 274H.
Specs are as follows:
Duration 230/236 @0.050 inches
274/286 measured @ .006 tapper rise
Lift int .488/exh .491.
The engine is a 1968 440 with 10:1 compression. Is there anyon out there who knows what the vacuum would be on a setup like this?

I like the hydroboost idea, but holy cow is it expensive!!!!!!
Thanks!!!!

[sassygreen]

check out my post [ rv budget build ] I used an extreme energy cam. I will check vacuum and get back later.

[Chryco Psycho]

I will estimate around 12" of vacuum @ idle in gear so vacuum boost will be poor , hydroboost can be done much cheaper if you are creative , go get a boost unit from the wrecker , you will need to make hoses & mount & pushrod

[crash340]

another option is an electric vac pump off a modern car, as an example http://www.ebay.com/itm/Power-Brake-Booster-Vacuum-Pump-ACDelco-GM-Original-Equipment-22819443-/400963975020

Hydroboost is fantastic for sure but if your limited the above could be an option

[magoo426]

Thanks sassygreen for measuring that for me! How do you like your cam?

CP, im little concerned about building my own hydro booster brake system. I think id better leave that to people more experienced. But im still thinking about one though.

Crash340, have you used that electric vac pump before? Im wondering how well that works to.

[sassygreen]

This is by far the best cam I ever bought. 14 inches of vacuum at idle shakes my shaker hood just right, will do rolling burnouts. Let it roll out about 3 or 4 mile an hour mash the gas burns tires in first, shifts to second and continues to fry the tires till it hits drive. With a 727 and a 8 3/4 rear end with 2.73 gears. Cruises 65 70 miles an hour right at 2,000 rpms. No stall on the converter, stock. I love it

[magoo426]

Thanks again for measuring the vacuum for me sassygreen!!! I appreciate it!!  What type of brake setup are you running (all disc), what type of brake booster do you use?  Do you have any problems with your brakes not working well?  Any info I can get from you will really help me out.  I'm just not sure what I should do about my brake booster.  I will try to call Willwood Thursday and tell them I will be running about 14" of vacuum.

What engine compression are you running?  Do you know how much HP and Torque your engine is putting out?

Thanks again for your help and time to measure your vacuum for me!!!!!!!

[sassygreen]

Now as far as the brakes go it is a factory 1974 barracuda set up. Power brakes, front disc rear drum, Power steering. At the moment my brakes work but the pedal travel is more than I like. I am going to go with one of the newer plastic reservoir brake master cylinders, they have a larger bore, and the aluminum adapter block. As far as the power brake part of it, I think it works ok. I start the car with a firm foot on the brake and when the car fires the brake pedal travels about an inch. As far as the horsepower and torque, I don't know. There is no dyno near me, but I sure would like to strap it down to one. I can tell you that anything around 1/4 pedal from a dead stop it is laying rubber. Crazy torque right off idle. I love to bark the tires when I take off because it is so easy. My idle is around 850, 14 inches of vacuum. I can get 15 inches of vacuum at 1000 rpm. But with the idle that high you might get run on when it is hot outside.

[magoo426]

Called Willwood and told them my vacuum would be around 14".  They said that to run the front and rear 4 piston caliper disc brakes would need 18" vacuum.  They recommended either doing manual brakes or going with a Hydroboost.  Has anyone on here used anything else to help increase vacuum for brakes?  I'm having a hard time swallowing paying for the hydroboost options.

Thanks!

[Cudakiller70]

check out my post [ rv budget build ] I used an extreme energy cam. I will check vacuum and get back later.

Is this it sassy green?   RV 440 low budget
http://www.cuda-challenger.com/cc/index.php?topic=101489.0

[sassygreen]

yes, that is the thread. I never got around to updating it at the end. Got tired of everyone telling me I needed to do this and do that. How affordable the stroker motors are bla bla bla. My brakes work. Try it out for yourself first before you go buy some high dollar hydroboost.

[Cudakiller70]

yes, that is the thread. I never got around to updating it at the end. Got tired of everyone telling me I needed to do this and do that. How affordable the stroker motors are bla bla bla. My brakes work. Try it out for yourself first before you go buy some high dollar hydroboost.

I think you should update It, sounds like it turned out real well! I went  to your thread because after reading how well you said it was performing, I was interested. I would like to know how you finished it and what where your final $?  Jim