Just joined? Please introduce yourself.
Page 1 of 3 123 LastLast
Results 1 to 10 of 28

Thread: Hydraboost or 13 inch disc to upgrade braking

  1. #1
    Registered Member Bihili's Avatar
    Join Date
    Sep 2012

    Member #:896
    Location
    outside K. C.
    Posts
    267

    Hydraboost or 13 inch disc to upgrade braking

    I am not satisfied with the current 10 1/2 front disc and rear drums on 12 bolt rear end.
    Because of the small supercharger I have an electric vacuum pump and additional tank which produces 18 inches of vacuum.
    This is barely enough for the vacuum booster.
    It feels like the brakes will not lock up, maybe because of the large tires, 245 & 295's

    Which upgrade do I need?
    Larger front disc or hydroboost?
    Last edited by Bihili; 11-13-2017 at 07:56 AM.
    Bill 1957-427-177-6-410

  2. #2
    Banned
    Join Date
    Nov 2015

    Member #:2775
    Posts
    1,426
    The hydro will add more pressure with less effort, but it won't improve your brake stopping ability unfortunately. You should be able to lock them up if you push hard enough unless the pedal is to the floor. If so you need more brake grip. Cylinder sizes are another thing to look at.
    Last edited by 55 Rescue Dog; 11-12-2017 at 03:05 PM.

  3. #3
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    In your situation I'd do both. Install the hydroboost first and see if you're happy with the braking....I believe it will improve and you can get rid of the vacuum pump and booster. But beyond that I'd go with bigger front brakes if you can fit them inside your wheels.
    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

  4. #4
    Registered Member
    Join Date
    Apr 2012

    Member #:571
    Posts
    4,671
    How big is your booster and is it single or double diaphragm? What bore size on the master cylinder? Do you have a gauge on the vacuum reservoir? If so what is the typical vacuum reading?

  5. #5
    Registered Member Bihili's Avatar
    Join Date
    Sep 2012

    Member #:896
    Location
    outside K. C.
    Posts
    267
    Duel 8 inch diaphragm with one inch bore master cylinder.
    The vacuum pump kicks off at 18 inches of vacuum.

    17 inch wheels on front would allow a 13 inch rotor.
    Last edited by Bihili; 11-12-2017 at 06:50 PM.
    Bill 1957-427-177-6-410

  6. #6
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    I think I changed my mind on the order of the improvements. With 17" wheels I think the 10.5" rotors probably not only LOOK a little wimpy, but they probably are small for your setup. For both looks and performance I think I'd do a rotor and caliper upgrade to at least 12" rotors first....11" isn't much of an upgrade, imo. That should help assuming everything else is working correctly. I don't know what calipers you're using now but if you go to multiple or larger pistons that take more fluid volume, you may end up with more pedal travel than you like with the 1" master cylinder, so you may have to increase the master cylinder bore size .....then you need a better booster. It's all kind of a balancing act and you have to optimize the setup.
    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

  7. #7
    Registered Member
    Join Date
    Aug 2015

    Member #:2643
    Location
    Tampa, FL
    Posts
    428
    Change to the 13" front brakes. Like Laz said, you might have to change your master cylinder as a result.

  8. #8
    Registered Member
    Join Date
    Apr 2012

    Member #:571
    Posts
    4,671
    Many of the caliper upgrades are actually smaller bore size even with 4 or 6 pistons, so would require either no change or a smaller master cylinder. The Wilwood 6 piston is that way, as are C4-C6 Corvette calipers. You need to make sure the master cylinder matches the calipers. Remember that a smaller master cylinder will produce more pressure for a given push with the pedal - but the travel goes up too.

    I think what you have to determine here is whether you have inadequate boost or just not enough brakes. Lots of cars seem to do fine with the metric brakes, but obviously bigger rotors with a caliper upgrade will be better.
    Last edited by Rick_L; 11-13-2017 at 09:08 AM. Reason: changed "caliper" to "master cylinder" in last sentence of first paragraph

  9. #9
    Registered Member
    Join Date
    Aug 2015

    Member #:2643
    Location
    Tampa, FL
    Posts
    428
    Quote Originally Posted by Rick_L View Post
    Many of the caliper upgrades are actually smaller bore size even with 4 or 6 pistons, so would require either no change or a smaller master cylinder. The Wilwood 6 piston is that way, as are C4-C6 Corvette calipers. You need to make sure the master cylinder matches the calipers. Remember that a smaller caliper will produce more pressure for a given push with the pedal - but the travel goes up too.

    I think what you have to determine here is whether you have inadequate boost or just not enough brakes. Lots of cars seem to do fine with the metric brakes, but obviously bigger rotors with a caliper upgrade will be better.
    I think you meant a smaller master cylinder, right?

  10. #10
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    10,835
    Bill, do you have a brake pressure gauge you could install to see what kind of line pressure you're getting out of the MC? That might help answer some questions.
    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

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •