Regarding the drilled drum brake idea

Discussion in 'Technical' started by Positively Ralf, Mar 7, 2010.

  1. Positively Ralf

    Positively Ralf Here and There

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    Guess this would be towards the people who run high powered engines. Have any of you ever considered drilling the drums in the back(if you still have em) after converting to front discs?

    I was just thinking about this while reading through some older topics and was curious to know if anyone has even considered this idea.
     
  2. baddad457

    baddad457 Member

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    No point in doing that unless you're heavy into the road race scene.
     
  3. maverick75

    maverick75 Gotta Love Mavs!

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  4. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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  5. Bluegrass

    Bluegrass Jr. mbr. not really,

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    MOJO, some comments on your brake experiment.
    What is your basis for improved brake performnce?
    Braking depends on friction between the shoe and the drum.
    Drilling holes reduces the available surface area and reduces that friction.
    Only thing holes would tend to do is provide extra ways for the gases developed under hard braking, to escape but not add to friction or improve fading.
    Under servere braking and repeated heating, expect the drums to warp and develope cracks around the drilled holes.
    Further, best braking is dependent on the front to rear weight, tire traction, brake friction material performance among other things.
    There is a balance to atain with all these parameters such that a change in any one can greatly change the overall results.
    Said another way, there is a lot of enginerring that goes into braking systems.
    For example; if you were to increase rear braking grip a good amount, would you not expect the rear traction to brake loose on heavey braking instead of the front and rear ataining a balance to get max braking from all 4 wheels at the same time? What would you do about it if that were the case?

    There is a large amount of science behind all this that needs to have full attention paid to the complete system balance.
    When the factory designs and tests their OEM systems, it has to not lock up either front or rear, not wear either set of friction material singley 'in excess', have reasonable fade resistance and is pegged to a tire size and weight of the car plus suspension weight transfer to the front under hard braking.
    From this you can see that tire size, suspension, brake friction area, brake friction material, brake bias control from the master cylinder, total weight etc are all critical players in total braking results.
    Sorry to sprinkle on your efforts but you should be awhere of these things.
    Even on a stock car new or old, when changing anything away from what the factory supplied, changes the overall result from the original design.
    Not saying improvement can't be done but it takes more than just one simple change.
    Best single improvement in any brake system is to install higher friction materials on all 4 wheels at the same time, of the same type material assuming no other changes have been done to change other dynamics.
    Hole drilling is an age old thing done on street and race car discs and usually has a down side a short time later in cracking and warping to the point of short life spans.
    Only time vented discs have any long life is when a company builds the disc with 'cast in' holes and extra design strength for servere duty but are still expected to be changed more ofen under performance use.
    In any event, good luck.
     
  6. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    Bluegrass:
    I appreciate all ur comments. As u say it's an experiment. I chamfered all the holes to hopefully reduce the possibility of cracking. As u say, I intend to reduce gases, reduce heat buildup, centrifically force any water frm the drums. It seems as u know a lot abt this subject. Im not using the car where it normally wud be subject to heavy braking. Anyway, I will keep a close watch on the drums and if I determine they are unsafe (cracking) I will replace them in a heartbeat - drums are abt the least expensive part of the system and the easiest to replace.
     

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