Are slotted/drilled/dimpled rotors worth the extra cost? - Defender Source
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  #1  
Old November 13th, 2013, 08:57 AM
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Are slotted/drilled/dimpled rotors worth the extra cost?

Anyone have any seat of the pants experience or particular affinity for the "augmented" brake rotors? Other than the looks, do they offer any real benefit over the regular ones?
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  #2  
Old November 13th, 2013, 09:11 AM
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I have the drilled/slotted solid front rotors from Lucky 8. I think terra firma, not sure, they were part of a package a few years ago. Anyway, with the solid flat rotors the brake pedal was useless after going through a water crossing. Now it is better, as there is somewhere for the water to go. Aside form that, not much difference. They still suck when they are covered in mud as I discovered this past weekend. Probably didn't help that the right rear hub seal is gone and soaking the rotor in grease and 90 weight. Guess it is time for that long avoided bearing/seal/rotor job.

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Originally Posted by o2batsea View Post
Anyone have any seat of the pants experience or particular affinity for the "augmented" brake rotors? Other than the looks, do they offer any real benefit over the regular ones?
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  #3  
Old November 13th, 2013, 09:15 AM
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In a street application? No. Especially not on a Defender.

The slots and dimples are really designed to give benefit in very high heat conditions, which likely won't be reached on a street-driven vehicle. They do shed water better and thus have better initial bite than a solid-faced rotor in wet conditions, but I haven't felt any performance differences short of that.
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  #4  
Old November 13th, 2013, 09:20 AM
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There is no benefit for our application. Purchase the cheapest blanks not made in China. Anything more is a waste of $$.
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  #5  
Old November 13th, 2013, 10:27 AM
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no, less surface area
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  #6  
Old November 13th, 2013, 04:55 PM
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Drilled rotors are a waste of money in every application including racing. The only exception is Porsche & Brembo both of whom hold a patent on a manufacturing process that alleviates a lot of the draw backs. It's an urban legend that they help reduce heat. They actually increase heat by taking the same amount of friction into less material. For off roading they are especially bad since the mud gets in there and then you hit the brakes on the street and boom.. you now have lumps of hardened clay in your rotors causing a balance issue.

Performance can be gained from slotted rotors which reduces glazing on the pad but this is really only applicable in racing situations where the pad temperature is exceeding 800 degrees. For solid rotors.. check out Frozen Rotors. They are a dramatic improvement over a normal setup. I got 3 times the life span of a non cryo treated rotor on my race car with little to no fatigue of the metal

This info is only pertinent to steel rotors.. ceramic is a whole different ball game..
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  #7  
Old November 13th, 2013, 05:13 PM
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Quote:
Originally Posted by sflash868 View Post
Drilled rotors are a waste of money in every application including racing. The only exception is Porsche & Brembo both of whom hold a patent on a manufacturing process that alleviates a lot of the draw backs. It's an urban legend that they help reduce heat. They actually increase heat by taking the same amount of friction into less material. For off roading they are especially bad since the mud gets in there and then you hit the brakes on the street and boom.. you now have lumps of hardened clay in your rotors causing a balance issue.

Performance can be gained from slotted rotors which reduces glazing on the pad but this is really only applicable in racing situations where the pad temperature is exceeding 800 degrees. For solid rotors.. check out Frozen Rotors. They are a dramatic improvement over a normal setup. I got 3 times the life span of a non cryo treated rotor on my race car with little to no fatigue of the metal

This info is only pertinent to steel rotors.. ceramic is a whole different ball game..
Agree that drilled rotors are a waste, but not so sure that Brembo has them figured out. I ran a set at Watkins Glen this spring because Amazon was selling for $140. Almost lost a large chuck out of one of them after 3 hours of test and tune and 14 hours on the weekend. The drilled holes provides additional surface area for cooling, but also creates stress risers with the differential expansion. Note where all those cracks originate from! WG is easy on the brakes, too (unlike full course CMP that eats them up). When pitting, fronts didn't exceed ~ 420F and 490F on the rears. PFC 06 and 08 compound pads. Most in crap can racing put the money elsewhere and run cheap $35 blanks a corner. Pads is the killer (and try PFCs if you haven't). About the same cost as tires over the season.
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  #8  
Old November 13th, 2013, 05:36 PM
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The cheap brembo rotors.. 100% terrible. I seem em pop up on tirerack. However their gold big brake kits do have some quality in them but I still would avoid drilled at all costs unless they were ceramic for the exact reason in your photos.

WG not hard on brakes? man you must have one light car.. I gotta haul 3100 pounds from 145 down to 60 for the bustop not to mention the laces.. the toe and turn 1. I boil super blue almost every time I go there. I haven't tried PFC but they are on my list next year. You want value.. run Pagids. I get an entire season out of Pagid blacks on the front and 2 seasons out of oranges on the rear. Very easy on the rotors too but they don't have a great initial bite. Which group do you typically run with?
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Old November 13th, 2013, 06:40 PM
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An ~ 2300lb E30 w/ a junkyard pull in Chumpcar and LeMons. 125 mph approaching the bus stop. A few run E36 hubs and $2000 big brake kits and take the penalty laps. Nothing more than bling on these cars. Have fun finding SuperBlue! It only took the Feds 15 yrs to pull it off the shelves. Thankfully we still have a few L left and alternate it with the gold ever other race.
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  #10  
Old November 13th, 2013, 08:06 PM
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So if the holes are drilled by Brembo or Porsche, its different than Terrafirma? Are they drilled by Asian dwarfs in estrogen baths? That would explain the premium price I guess.

Since I would venture to say none of us take our Defenders on Watkins Glenn, anyone with real world experience with drilled/slotted rotors on Defenders care to share. The only example from Ching above is neutral to positive compared to solid...

I have a full set of the TFs in the garage...getting scared.
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  #11  
Old November 13th, 2013, 08:15 PM
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Hahah. You see CNN's article about the "Asian Unicorn" today... anyway.. Porsche and Brembo don't drill them, that's the main difference. Most providers of drilled rotors buy cheap blanks from China and simply run em through a drill. That process leaves stress points leading to the pictures you see above. The alternative is to build a mold and actually cast the rotor with the holes in it but it's much more expensive and most manufacturers don't do it.

Love running in Lemons.. we race a white Ford Escort in class C. probably been in races with you. We won Class C this year at NJMP. Autozone brake pads in that thing.. cost 10 bucks with a warranty. amazing.
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Old November 13th, 2013, 08:23 PM
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Quote:
Originally Posted by down_shift View Post
Have fun finding SuperBlue! It only took the Feds 15 yrs to pull it off the shelves. Thankfully we still have a few L left and alternate it with the gold ever other race.
I would have liked a warning about that. I have a few bottles of Blue left. A buddy of mine was trying to get it from me and told me about it getting pulled from the market.
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  #13  
Old November 13th, 2013, 08:28 PM
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I didn't even know it was pulled from the market. Most of the suppliers i get it from still have it. Maybe it's a different super blue..
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  #14  
Old November 13th, 2013, 09:40 PM
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Quote:
Originally Posted by sflash868 View Post
I didn't even know it was pulled from the market. Most of the suppliers i get it from still have it. Maybe it's a different super blue..
It is one in the same. As of 08/15/13, it is against the law to sell the ATE SuperBlue. Continental stopped distributing it and recalled about 480,000 units. The Feds have a color requirement for brake fluid so it can be easily identified - colorless to amber.
We ran the LeMons race at NJMP this summer. Great track and venue. Put in a 4:10LSD just for Thunderbolt. Running 7th until the tranny let go on Sunday. Congrats on your class win!
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  #15  
Old November 13th, 2013, 09:46 PM
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Venting and cross drilling are not the same FYI. Cross drilling was invented to help with outgassing. I don't think any pads still "out gas". Its 100% looks. I prefer slotted rotors for posing though.
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Old November 16th, 2013, 08:03 AM
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brake rotors

I put EBC slotted and dimpled rotors on my '97 D90 with EBC GreenStuff pads. When cold, I had such a difficult time stopping the truck that I replaced the pads with a more "stock" approach and have been pleased since. I was using the truck in mostly hot and dry climate with no mud. Did the rotors make a performance difference? For my application it's really hard to tell. The rotors have held up well and still look good over 10K and 2+yrs.

I also put drilled and slotted rotors purchased off eBay and Ferodo pads on a '95 LR3 that sees mostly highway travel. I get a lot of brake dust but attribute that to the pads. They work well and have held up well over 30K and 3+yrs.

I wouldn't shy away from installing yours but, as several others have noted, you're probably not going to see a huge difference from the rotors unless you're on a track - which will be highly unlikely. From my experience, where you're going to find the biggest difference is in the pads.

Cheers
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  #17  
Old November 17th, 2013, 06:09 AM
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total waste of time and money. Don't even look good for long if you actually use them.
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