Drilled/slotted rotors on a street car good idea or bad?

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Offline brads70

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Drilled/slotted rotors on a street car good idea or bad?
« on: November 08, 2010 - 08:05:17 PM »
I've heard/ read different schools of thought on drilled/slotted brake rotors on a street car.
Some say it helps with dissipating gases/dust and cools better both due to more surface area and more air moving?
Some say it takes away surface area so less braking ?
I don't know what to think.... :clueless:  They both sound logical?
Is it one of those things from racing that's better suited for race cars and just used as a marketing tool?
Brad
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Offline moparmaniac59

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #1 on: November 08, 2010 - 08:19:16 PM »
I think the loss of surface area would be very minimal, especially since it's a moving surface. I have not researched it much, but believe in the statement that it will cool much faster and help disperse dust/dirt. I think they are very common now on motorcycles. Why not on more cars?? I think it's a good move, but I've not really looked into the cost. I know I rode in a break-neck nine second street car (and it was a Plymouth Duster) and he was using a 4-wheel disc brake system with drilled slotted rotors and the stopping force (negative G's) almost caused my brain to slip out my eye sockets!!  :22yikes: So to put it simply....it stopped on a dime!!  :2thumbs:

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Offline Topcat

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #2 on: November 08, 2010 - 09:11:16 PM »
For street, I would just go slotted.  :2cents:

If you plan to drive a restored E body like a maniac on the streets all the time, I can understand upgrading the brakes all the way around.

I certainly don't plan to since if you get caught out here, you could get your car confiscated. Or get in a bad wreck.
Mike, Fremont, CA.


Offline 71cudajoe

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #3 on: November 08, 2010 - 09:13:46 PM »
Below is a quote I pulled from another website regarding this topic. It speaks to all the advantages and disadvantages I learned about when I was researching it myself a couple years ago.

"What advantages do drilled and slotted rotors have? The most notable is they have an increased surface area to allow better cooling. Other advantages include lower rotational mass, better off-gassing properties, and increased wet performance. Do they run cooler? Yes! Based on the average of several controlled data samples these rotors run on average 82º cooler in the front and 27º cooler in the rear. The downside to drilled and slotted rotors, other than cost, is they are more prone to warp if not torqued correctly. They can also make a slight whirling noise during hard breaking."

I installed drilled and slotted rotors on all 4 wheels, but I have to admit, though, that I did not go with them for performance. I figure with the way that I will drive my car, I wouldn't experience any sort of difference between regular rotors and the drilled/slotted ones. I simply went with the drilled and slotted rotors for the looks.

« Last Edit: November 08, 2010 - 11:02:41 PM by 71cudajoe »
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Offline brads70

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #4 on: November 08, 2010 - 09:59:46 PM »
Lots of great imput!  :2thumbs:
I ask as I'm rounding up parts for my C-body spindle project , and am wondering about getting the drilled and slotted Rotors. Lots of vendors on E-bay.  They really are not that much more as compared to buying stock rotors from my local jobber.( Taxes suck here, I get parts shipped to my inlaws in PA to save the taxes)
I have the R-Body, big rotor set up now with drilled and slotted, but the pads REALLY suck!   REALLY SUCK! Fade bad! I bought firm feel pads to try but I have a buddy I can get Viper calipers from at a good deal! So I might go that route too?
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
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Offline dodj

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #5 on: November 08, 2010 - 10:05:39 PM »
I've heard that cross drilling gives heat related stress cracks somewhere to start. Is it true? I dunno.
My 2008 Altima doesn't have slotted rotors and it stops great. Probably about 600 pounds lighter, but my 3500 diesel stops pretty good too, no slots, no drilling and it's about 3500 pounds heavier.
I'd go with the slots if you really like nailing the brakes heavy and often. You gonna auto-cross with that 440? :woo:
Scott
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Offline BIGSHCLUNK

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #6 on: November 08, 2010 - 11:17:07 PM »
I've heard that cross drilling gives heat related stress cracks somewhere to start.

Thats been my (very linited )(late model stock car) experience. Nonwithstanding I do have slotted on NIKKI. But I really have never consistently really worked my brakes really hard. But I do run 4 piston calipers... it dosent seam to take as much effert.  :dunno:
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Offline Super Blue 72

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #7 on: November 09, 2010 - 03:12:32 AM »
If it ever comes time that the cross drilled/slotted rotors need to be resurfaced, can they be resurfaced on a standard brake lathe?  :clueless:


Here'some interesting reading on the subject of cross drilled/slotted rotors.  Take it for what you will, but none the less informative.

http://www.8thcivic.com/forums/suspension-brakes/92039-cross-drilled-rotor-myths-dissolved.html
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Offline brads70

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #8 on: November 09, 2010 - 07:42:38 AM »
Thats been my (very linited )(late model stock car) experience. Nonwithstanding I do have slotted on NIKKI. But I really have never consistently really worked my brakes really hard. But I do run 4 piston calipers... it dosent seam to take as much effert.  :dunno:
Ya I have seen that at the speedway too. But that was after heating up the rotors till they glowed orange. I'll never get there.
What calipers are you using?

Dodj, no I don't plan on autocrossing it ( 440  :smilielol:) Never seen that sort of racing around here, mind you it might be fun to try, but with the 440 I doubt it would be very competative!
I just think that when you have to buy parts , ya might as well get the best parts available, esp with brakes!
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
Proud to own one of the best cars ever made!!!!!

My restoration thread 
http://www.cuda-challenger.com/cc/index.php?topic=59072.0
 My handling upgrade post
http://www.cuda-challenger.com/cc/index.php?topic=73985.0

Offline brads70

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #9 on: November 09, 2010 - 08:02:31 AM »
If it ever comes time that the cross drilled/slotted rotors need to be resurfaced, can they be resurfaced on a standard brake lathe?  :clueless:


Here'some interesting reading on the subject of cross drilled/slotted rotors.  Take it for what you will, but none the less informative.

http://www.8thcivic.com/forums/suspension-brakes/92039-cross-drilled-rotor-myths-dissolved.html


Good read, Ya that's the other side of the coin huh?  I still don't know what way to go? :grinno:
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
Proud to own one of the best cars ever made!!!!!

My restoration thread 
http://www.cuda-challenger.com/cc/index.php?topic=59072.0
 My handling upgrade post
http://www.cuda-challenger.com/cc/index.php?topic=73985.0

Offline tommyg29

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #10 on: November 09, 2010 - 08:25:41 AM »
do your research before buying because the cheap ones WILL crack and/or warp much more easily.
The way some of them are drilled makes them more prone to cracking at the holes.
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Offline Strawdawg

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #11 on: November 09, 2010 - 08:55:33 AM »
X2

Slots are good, drilled are usually not that well considered for a driver altho the dimpled versions are not prone to potential cracking....

I suspect the biggest concern with the ebay versions will be warped long before one has to worry about cracks and such....

Offline aris_unlimited

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #12 on: November 09, 2010 - 09:02:06 AM »
I've heard a couple of reasons that drilled slotted rotors aren't useful for anything other than track use. Mostly people saying that it weakens the rotors making them crack.

I don't think these people are 100% correct lol. Every modern day motorcycle I have seen has drilled and slotted rotors from the factory. Going with my way of thinking since cars weigh quite a bit more you need heavier duty rotors, but I think they should work fine. My theory is that most of the people that have the ones that are cracking are buying cheapies. With something like this I wouldn't skimp on price. Buy the quality pieces and they will probably last longer.

All that being said, I still have no idea which rotors I'm going to go with lol. But then again I haven't really figured out how I want to do my braking system in general.
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Offline HP2

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #13 on: November 09, 2010 - 10:33:39 AM »
My vote; on a classic street car, under normal street conditions, no difference.

If you were planning on heavy competiton, you would either be looking at the cheapest possible way to buy these as a consumable or dropping big coin for crygenically treated steel or carbon. Even then, your pads are a bigger factor than the rotor and its particular features, or lack there of.

Slotted rotors will help if your driving in wet conditions regularly, otherwise, I don't see a huge gain in street use. If they are only slightly more costly than solids, then it is a personal call for the sake of appearences.
« Last Edit: November 09, 2010 - 10:54:32 AM by HP2 »

Offline the_engineers

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Re: Drilled/slotted rotors on a street car good idea or bad?
« Reply #14 on: November 09, 2010 - 10:39:14 AM »
I'm running the same ones Brad has...but mostly 'cause they look cool.  If I remember right, they were only slightly more than parts store replacements...
Brooks

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