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Old 09-13-2013, 11:01 PM
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Drilled drum brakes??

Hey everyone,

Been doing some reading up on brakes, friction material ect. I came across some articles and people drilling drum brakes. From what I see the main advantage is outgassing (probably not a real advantage with modern shoes) And they aid in cleaning, keeping the shoe de-glazed.

I read a GM article where drilled rotors did in fact increase the drag coefficient. I would suspect drums would be the same. Lets hear your thoughts and if you have ever used drilled drum brakes.

Thanks

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Old 09-14-2013, 06:07 AM
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Never used them but have thought about it, they have been venting the rear drums for over 25 yrs i know actually alot longer, they started doing it on the old race cars back in the day, and if it does in fact help with stopping power and cooling with the drum brakes then venting the drums would be a good thing for the rear as is for the drilled rotors. JMO


Cole
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Old 09-14-2013, 08:11 AM
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NHRA Rulebook, General Regulations 3.1, Brakes:

Lightening of backing plates, brake drums, and/or brake shoes by cutting or trimming metal
prohibited. Cooling or lightening holes may not be drilled in cast iron disc brake rotors.

Author's Note: Aftermarket disc brake rotors are not cast iron. OEM rotors are cast iron.
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Old 09-14-2013, 08:30 AM
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I think the "cooling fins"on your drums do a good enough job.
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Old 09-14-2013, 09:27 AM
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air ductiong.

a lot of old race cars had cold air ducting to the brakes.
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Old 09-14-2013, 11:14 AM
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there are some aluminum brake drums available,no idea why you wouldn't just upgrade to disc?
Drum brakes work quite well they just dont cool as fast as disc brakes ,so,,,for road racing disc brakes are better.If you drive an occasional 1/4 mile pass and the car is slow,you have plenty of time to slow down before the last exit
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Old 09-14-2013, 12:19 PM
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Are we talking about drilling the braking surface of the drum or the side of the drum to assist cooling?
A drilled disk brake rotor is on the braking surface, I figure drilling a drum wouldnt be.
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Old 09-14-2013, 12:38 PM
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Sounds like a pretty good deal to me.

Drilled Drums
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Old 09-14-2013, 01:54 PM
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And guys alot of old race cars didn't have dics brakes at all and no cooling fins on the drums.Hell NASCAR has cooling ducts on their current cars,but then again when do you ever expect to head towards a curve at 200 mph for 500 miles??.
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Old 09-14-2013, 02:33 PM
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i think you'd be better of cutting grooves across the face of the drum
it would cool the shoes better, they wouldn't last but a pass or 2 but your cooling would be exceptional
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Old 09-14-2013, 06:32 PM
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Quote:
Originally Posted by poncho62 View Post
Are we talking about drilling the braking surface of the drum or the side of the drum to assist cooling?
A drilled disk brake rotor is on the braking surface, I figure drilling a drum wouldnt be.
Yes Poncho, they do it both ways for cooling and i,m sure it started out for that and other reasons. and we are talking about on a street car i am anyway not a track car of any kind.


Cole
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Old 09-14-2013, 06:46 PM
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also,you can use riveted shoes instead of bonded shoes.order(custom) brake material for the shoes. Use wheels that promote fresh air circulation.,,,,
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Old 09-14-2013, 06:47 PM
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I'm talking about drilling the drum braking surface.
WPS:AMC:1963 Rambler American

People who have actually done it say it helps with brake fade and increases brake bite.
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Old 09-14-2013, 08:12 PM
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I would be concerned about causing stress risers at the drill holes. The holes would need to be chamfered on both sides to hopefully prevent this. Even then there's the concern (for me) of warpage caused by the holes. The holes would need to be drilled so as to have them equidistant from each other, then the drum should be rebalanced for best results. I would be concerned about dirt/sand entering the brakes through the holes in the event the vehicle was driven through puddles, etc.

All in all, I think your time and energy would be better spent elsewhere.
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Old 09-15-2013, 04:03 PM
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Quote:
Originally Posted by cobalt327 View Post
All in all, I think your time and energy would be better spent elsewhere.
There's the bottom line.
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