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Thread: brakes

  1. #11
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    .Stock pedal ratio is 6:1.

    If the master cylinder is at stock height, the pushrod will be level and the clevis will line up with the original hole in the brake pedal arm and you'll have the 6:1 ratio.

    If you re-drilled a new clevis hole 1" down from the original, you'll have a 4:1 ratio. It's usually used with angled vacuum booster mount. 6:1 ratio means you have 50% more pedal travel but 50% more line pressure than 4:1. You need a pretty hefty booster to make up for that. Or conversely, if the booster is dead or limited vacuum, you have to push real hard!

    You didn't mention what booster or master cylinder you have. Usually the Wilwood calipers need a smaller master cylinder than the typical GM calipers used in conversions, so you may need a smaller master cylinder if it was sized for GM calipers.

    If you feel you really need boost or a shorter pedal travel, as already suggested a hydroboost is the answer, especially if you already have power steering.
    Last edited by Rick_L; 01-19-2017 at 06:02 PM.

  2. #12
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    do you know what is a factory ratio for a 55 chevy

  3. #13
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    Quote Originally Posted by mikes55 View Post
    do you know what is a factory ratio for a 55 chevy
    Read Ricks last post he told you.

  4. #14
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    looks like you are pretty familer with this. yes I did have the CPP conversion and I called and it is a 1/18 bore master cylinder I have now. I called wildwood and they suggest a 15/16 bore if I go manual with the 6:1 ratio would be what I need. do you believe that combination would be just as good as power. in Bowling Green the last 2 years most of the cars had nanual brakes. I am also running a 7'' booster because of valve cover clearance.

  5. #15
    Registered Member chevynut's Avatar
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    I personally don't think you'll ever get manual brakes to perform as good as power brakes. If you could, car manufacturers would be doing it. I also think most of the guys using manual brakes are doing it for looks, not performance. A big vacuum booster is ugly, takes up lots of room, and often interferes with the engine. A hydroboost is better in that respect, but it's still "ugly" in a way. They work great though, if you have power steering. IMO the best looking boosters are the ones ABS Power Brakes sells...they're electric and look like a regular master cylinder. They're expensive but you see them on high end builds and you might actually be seeing that on those "manual brake" cars.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
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    2003 Chevy Silverado 2500 HD Duramax
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  6. #16
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    Quote Originally Posted by chevynut View Post
    I personally don't think you'll ever get manual brakes to perform as good as power brakes. If you could, car manufacturers would be doing it. I also think most of the guys using manual brakes are doing it for looks, not performance. A big vacuum booster is ugly, takes up lots of room, and often interferes with the engine. A hydroboost is better in that respect, but it's still "ugly" in a way. They work great though, if you have power steering. IMO the best looking boosters are the ones ABS Power Brakes sells...they're electric and look like a regular master cylinder. They're expensive but you see them on high end builds and you might actually be seeing that on those "manual brake" cars.
    I agree with most of this and would add that the bigger the cam the trickier it is to get good performance with a vac. booster. It is possible to get good stopping without power assist, my 56 is an example of this, while my 55 has issues that I am addressing.

  7. #17
    Registered Member BamaNomad's Avatar
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    The only thing a booster does is reduce the driver's pedal effort; it does not affect the actual brakes, or the car's 'braking ability' at all. If the driver has enough leg strength and control to depress the brake pedal to achieve the braking required, then he doesn't need a 'power booster'.

  8. #18
    Registered Member chevynut's Avatar
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    Quote Originally Posted by BamaNomad View Post
    The only thing a booster does is reduce the driver's pedal effort; it does not affect the actual brakes, or the car's 'braking ability' at all. If the driver has enough leg strength and control to depress the brake pedal to achieve the braking required, then he doesn't need a 'power booster'.
    Well you could say that about power steering too...if your arms are strong enough manual steering is fine. So are crank windows.

    If you can generate enough line pressure with your leg you're going to get the same braking as the same line pressure with a booster. The difference is the amount of force on the brake pedal....it's a lot less with power assist. It's not just about having enough strength, it's about comfort and effort to brake the car. I can't think of one new car that doesn't have power steering or power brakes.

    Sure manual brakes can work if you want to work 2-4 times as hard pushing the pedal. Also, as you move to a smaller master cylinder the pedal travel increases. There is a pretty cool device I saw from ECI (I think) that helps take up the pedal travel and reduce the brake pedal travel. It has a stepped piston arrangement.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  9. #19
    Registered Member BamaNomad's Avatar
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    Quote Originally Posted by chevynut View Post
    Well you could say that about power steering too...if your arms are strong enough manual steering is fine. So are crank windows.
    .... portions deleted....
    Absolutely... all that is true.. My first new car was a special order 1970 Roadrunner, 4-speed, Hemi suspension, F60-15 Polyglas GT tires, drum brakes all the way around, and NO Power Steering or Brakes... It was me and the car, and I loved it.. ... I did have to use a little 'go pedal for 'rear steer' when needing to make sharp turns at no/low speeds...

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