Crossdrilled or Not?

[speedminded]

Crossdrilling rotors has its advantages and disadvantages...they run cooler but are prone to cracking with extreme temperature differances ie. hitting a puddle during hard braking use. I don't foresee that happening because i doubt i'll be on the track in the rain and won't be driving hard on a wet street either (competition tires on a daily driver) Anyone have good or bad experience with any?

[Big Baller]

Crossdrilling rotors has its advantages and disadvantages...they run cooler but are prone to cracking with extreme temperature differances ie. hitting a puddle during hard braking use. I don't foresee that happening because i doubt i'll be on the track in the rain and won't be driving hard on a wet street either (competition tires on a daily driver) Anyone have good or bad experience with any?

Crossdrilled rotors do not in fact run cooler. They are prone to cracking. Slotted rotors eat pads. I can post up links to back up all this info if you like.

You are better off running regular rotors. If you go to Napa they generally carry two or three diffrent grade rotors for each car, just buy the best ones they have. Thats what I was open tracking my mustang on.

Matt

[speedminded]

Crossdrilled rotors do not in fact run cooler. They are prone to cracking. Slotted rotors eat pads. I can post up links to back up all this info if you like.

You are better off running regular rotors. If you go to Napa they generally carry two or three diffrent grade rotors for each car, just buy the best ones they have. Thats what I was open tracking my mustang on.

Matt

The original purpose of crossdrilling rotors was to help release the gases emitted from the asbestos brake pads during braking. Any object with more surface area is going to cool faster, those holes are no differant than the principal behind a heat sink. Besides they look better too As for grooved rotors...the caliper is an OEM rear from Porsche so the pads are dirt cheap.

http://forums.importatlanta.com/showthread.php?t=26848

I've been putting together a custom brake setup, the rotors will be ordered through AP Racing...it's not the typical one piece steel rotor, it's basically an outer ring bolted to an aluminum rotor hat/bell. It's actually the same rear rotor from a Modified circle track car...

[Big Baller]

The original purpose of crossdrilling rotors was to help release the gases emitted from the asbestos brake pads during braking. Any object with more surface area is going to cool faster, those holes are no differant than the principal behind a heat sink. Besides they look better too As for grooved rotors...the caliper is an OEM rear from Porsche so the pads are dirt cheap.

http://

I've been putting together a custom brake setup, the rotors will be ordered through AP Racing...it's not the typical one piece steel rotor, it's basically an outer ring bolted to an aluminum rotor hat/bell. It's actually the same rear rotor from a Modified circle track car...

1 Find me proof that cross drilled rotors cool better. When you drill a rotor you lose mass, that mass is what absorbs and dissipates heat from the brake system. Taking mass out of the rotors isn't going to make them work better.

2 If you are going to the track you shouldn't be worried about how they look.

3. Have you done any track days? Regardless of how cheap the pads are you don't want to have to change them at the track if you can avoid it. Keep in mind that you wont be using stock pads at the track you will probably be on something similar to a Hawk hp + or Hp 1 and those aren't cheap.

4. Check out Coleman Racing they generally have better prices on blank rotors. They will also custom machine hats for you if need be. I have a very similar setup on my 240 track car. I ended up with slotted rotors because at the time that's all they had. Ill post up some of the links I have and you can decide for your self if you really want drilled rotors.




2. How do you know that you want your rotors to cool better.( what you actually want is for your rotors to stay in a certain temperature range so that they work effectively.

[speedminded]

1 Find me proof that cross drilled rotors cool better. When you drill a rotor you lose mass, that mass is what absorbs and dissipates heat from the brake system. Taking mass out of the rotors isn't going to make them work better.

2 If you are going to the track you shouldn't be worried about how they look.

3. Have you done any track days? Regardless of how cheap the pads are you don't want to have to change them at the track if you can avoid it. Keep in mind that you wont be using stock pads at the track you will probably be on something similar to a Hawk hp + or Hp 1 and those aren't cheap.

4. Check out Coleman Racing they generally have better prices on blank rotors. They will also custom machine hats for you if need be. I have a very similar setup on my 240 track car. I ended up with slotted rotors because at the time that's all they had. Ill post up some of the links I have and you can decide for your self if you really want drilled rotors.

2. How do you know that you want your rotors to cool better.( what you actually want is for your rotors to stay in a certain temperature range so that they work effectively.

Both our Honda Challenge cars, all 3 of our Formula Mazda's, and Pro Formula mazda use plain face/blank rotors. i'm not arguing whether cross drilled is better or not...I just see them used in race applications and on nearly every motorcycle produced. Why i ask? I can understand for looks on a bike but what about $750,000-1,000,000 race cars? Are their crew members and engineers just as confused as i am? I would hope not.

Mass only dissipates heat because it has more exposed surface area. Why wouldn't a heat sink just be made as a simple square block if that wasn't true? BUT to go with your theory, it obviously takes less time to heat up less mass (a smaller pot of water will boil faster)...so by drilling holes or cutting slots then the rotor in theory it will heat up faster because there is less mass...BUT that resorts back to my theory on more exposed surface area means more heat dissipation...So would it all equal out at the end?

I can't access h-t from work so someone may have already done this on there but all the math and science in the world means nothing to most without putting it to test. I'll personally put a crossdrilled rotor on one side and a plain face on the other and test it myself. I'll use heat paint and a pyrometer to get the results and we'll see if in fact there is any and what differances. That's the only way.

In a 12 or 13 hour endurance race we'll go through 2 sets of hawk/carbotech race pads with the exact same brake setup using plain faced rotors on a 2,100 lb car (dry weight/del sol). Changing the pads on them couldn't be easier but my car isn't going to see competive racing for quite a while, if ever...I'll just stick with track days and mountain runs :-)

Really the only reason i would go with the crossdrilled is to show it off...i want to produce and market this kit and if it helps sell just 1 setup because it looks good then it's done it's job

[SNapper]

cross drilled are for show. go ask the companies that sell rotors. they will tell you NOT to use cross drilled rotors for track use.

[speedminded]

cross drilled are for show. go ask the companies that sell rotors. they will tell you NOT to use cross drilled rotors for track use.

i'm referring to JGTC for what they use...why, who knows....just seems like they should know what they are doing Some use cross drilled and some use slotted...the Takata NSX for example uses slotted only.

I'd like to start producing this kit, I have two other vehicles in mind and trying to obtain a control arm and hub from each to make a prototype.

[Big Baller]

Here is a fairly good link on Honda-Tech not one of the sites I frequent but pretty good info anyways.

http://www.honda-tech.com/zerothread?id=1437513

[obd1kenobi]

Matt I'll beat you with some used cross-drilled rotors, then buy your mark ass a drink!

[Vteckidd]

Plain Rotors, Carbotech pads, stainless lines, 91 EX master cylinder, thats all you need

[speedminded]

Plain Rotors, Carbotech pads, stainless lines, 91 EX master cylinder, thats all you need

but but..! I like to be differant, you know i've been talking about the calipers for nearly a year now, hell...bought them like 8 months ago and still haven't got them on.

I'm running the 2000-2001 ABS system too but the ridges on my passenger side axle are just about non-existant...not sure how that's gonna effect it.

[IntegraXTR]

91 EX master cylinder, explain?

[Vteckidd]

91 EX master cylinder, explain?

biggest master cylinder honda made besides the ITR , only came on the 1991 4 door EF EX model, rare to find

[Big Baller]

Heres a link

http://corner-carvers.com/altimathread.php.html

Its a long thread, feel free to discuss

More links less forums

http://www.teamscr.com/grmbrakes.htm
http://www.teamscr.com/rotors.htm
http://www.stoptech.com/tech_info/te...e_papers.shtml
http://www.howstuffworks.com/tire.htm
http://www.howstuffworks.com/fpte.htm

[KevinT707]

I'm willing to risk the cracks that are possible on drilled rotors & the slots that eat up brake pads. I just don't want it to happen to often, cause I just like they way they look. On average with normal driving how long would it take for me to go through some normal brake pads w/ drilled & slotted rotors, Big Baller? Cause it seems like its taking forever on my stock brake setup right now, I haven't replaced the pads in 2 years.

[speedminded]

I'm willing to risk the cracks that are possible on drilled rotors & the slots that eat up brake pads. I just don't want it to happen to often, cause I just like they way they look. On average with normal driving how long would it take for me to go through some normal brake pads w/ drilled & slotted rotors, Big Baller? Cause it seems like its taking forever on my stock brake setup right now, I haven't replaced the pads in 2 years.

I got a little over 40k miles out of my last set of brake pads and i've been working downtown for 2+ years too, plus all the mtn runs...wonders of a manual transmission and quality clutch

[mp5o]

IIRC The high end cars/race cars do not use cross DRILLED rotors. They are cast(or w.e.) that way. Take a somewhat thin piece of steel and try to bend it.... Wont bend right? Now drill holes in it.... Now it bends...

[Big Baller]

IIRC The high end cars/race cars do not use cross DRILLED rotors. They are cast(or w.e.) that way. Take a somewhat thin piece of steel and try to bend it.... Wont bend right? Now drill holes in it.... Now it bends...

No they arent, the holes are not cast. I will pay for a picture of the casting process where rotors are cast with the holes.

[mp5o]

No they arent, the holes are not cast. I will pay for a picture of the casting process where rotors are cast with the holes.

Im not 100%... Hence the IIRC. Its based off hearsay. Thanks for the correction.

[SampaGuy]

if the car is for the street, just get the plain brembos

[Vteckidd]

bottom line, when it comes to the best PERFORMANCE, its brembo blanks, good pads (hawk, carbotech panthers), stainless lines, an the best master cylinder for your vehicle.

go to honda-tech, post a topic in the autox an road race forum, i GUARANTEE 99.9% of the guys do NOT use crossdrilled or slotted rotors.

the questions you need to ask are:
how much braking am i doing?
how much HARD braking am i doing?
will my brakes see a benefit from cross drilled/slotted rotors?
what temp are my rotors getting to?
what is "too hot"?

most guys i know that seriously race, would rather spend the moeny on a custom brake duct or ram air induction to cool their brakes over crossdrilled or slotted rotors.

its like guys taht want to buy the $2000 fully adjustable dampening Tein suspension. i ususally ask them, "how often are you really going to adjust your suspension." the answer is usually they install it an never touch it again, so why spend the money on the adjustable setup then?

[speedminded]

Ok, i have read 1,000's of threads, posts, reviews, and tech articles...Even though i have found ZERO brake dyno or any other physical testing information as a whole it appears cross drilled brakes are purely cosmetic and only used as a hoax for the increased sales of higher end sports cars and more expensive "upgraded" brake systems.

Nearly every single company mentioned above that claimed that cross drilling offers no advantages does in fact claim somewhere that they operate cooler...from Power Slot to Brembo to AP Racing. Is it a scam? What's the deal? who knows?

[BLk92DA]

i have crossed drilled slotted rotors on all four. the braking is superb with ceramic pads...but im begining to see little cracks in the hole of the rotors(due to me washing car while hot)
i wouldnt suggest gettin these if you were to autox ect. just get whats best for your application

[Big Baller]

i have crossed drilled slotted rotors on all four. the braking is superb with ceramic pads...but im begining to see little cracks in the hole of the rotors(due to me washing car while hot)
i wouldnt suggest gettin these if you were to autox ect. just get whats best for your application

If you are seeing little cracks you need to throw them away now. They are trash, they could come apart at any minute.

[BLk92DA]

If you are seeing little cracks you need to throw them away now. They are trash, they could come apart at any minute.

squint your eyes little?

[mp5o]

Darrick Dong; Director of Motorsports at Performance Friction: "Anyone that tells you that drilling makes the disc run cooler is smoking crack."

Power Slot: "At one time the conventional wisdom in racing circles was to cross-drill brake rotors to aid cooling and eliminate the gas emitted by brake pads. However, today?s elite teams in open wheel, Indy and Trans Am racing are moving away from crack prone, cross-drilled brake rotors in favor of rotors modified with a fatigue resistant slotting process."

Stop Tech: "StopTech provides rotors slotted, drilled or plain. For most performance applications slotted is the preferred choice. Slotting helps wipe away debris from between the pad and rotor as well as increasing the "bite" characteristics of the pad. A drilled rotor provides the same type of benefit, but is more susceptible to cracking under severe usage. Many customers prefer the look of a drilled rotor and for street and occasional light duty track use they will work fine. For more severe applications, we recommend slotted rotors." (Note that even though Stop Tech sells both drilled and slotted rotors they do not recommend drilled rotors for severe applications.)

Wilwood: "Q: Why are some rotors drilled or slotted?
A: Rotors are drilled to reduce rotating weight, an issue near and dear to racers searching for ways to minimize unsprung weight. Drilling diminishes a rotor's durability and cooling capacity."

From Waren Gilliand: (Warren Gilliland is a well-known brake engineer in the racing industry and has more than 32 years experience in custom designing brake systems ...he became the main source for improving the brake systems on a variety of different race vehicles from midgets to Nascar Winston Cup cars.) "If you cross drill one of these vented rotors, you are creating a stress riser that will encourage the rotor to crack right through the hole. Many of the rotors available in the aftermarket are nothing more than inexpensive offshore manufactured stock replacement rotors, cross drilled to appeal to the performance market. They are not performance rotors and will have a corresponding high failure rate"

From Baer: "What are the benefits to Crossdrilling, Slotting, and Zinc-Washing my rotors?
In years past, crossdrilling and/or Slotting the rotor for racing purposes was beneficial by providing a way to expel the gasses created when the bonding agents employed to manufacture the pads...However, with today?s race pad technology, ?outgassing? is no longer much of a concern...Slotted surfaces are what Baer recommends for track only use. Slotted only rotors are offered as an option for any of Baer?s offerings."

Grassroots Motorsports: "Crossdrilling your rotors might look neat, but what is it really doing for you? Well, unless your car is using brake pads from the '40s and 50s, not a whole lot. Rotors were first drilled because early brake pad materials gave off gasses when heated to racing temperatures, a process known as "gassing out." ...It was an effective solution, but today's friction materials do not exhibit the some gassing out phenomenon as the early pads. Contrary to popular belief, they don't lower temperatures. (In fact, by removing weight from the rotor, they can actually cause temperatures to increase a little.) These holes create stress risers that allow the rotor to crack sooner, and make a mess of brake pads--sort of like a cheese grater rubbing against them at every stop. Want more evidence? Look at NASCAR or F1. You would think that if drilling holes in the rotor was the hot ticket, these teams would be doing it...Slotting rotors, on the other hand, might be a consideration if your sanctioning body allows for it. Cutting thin slots across the face of the rotor can actually help to clean the face of the brake pads over time, helping to reduce the glazing often found during high-speed use which can lower the coefficient of friction. While there may still be a small concern over creating stress risers in the face of the rotor, if the slots are shallow and cut properly, the trade-off appears to be worth the risk. (Have you looked at a NASCAR rotor lately?)

AP Racing: "Grooves improve 'cleaning' of the pad surfaces and result in a more consistent brake performance. Grooved discs have a longer life than cross-drilled discs."

...

[Big Baller]

no

[BLk92DA]

so no, as in they're ok correct?

[speedminded]

oh well, can't get the larger size rotor i wanted so stuck with 11.75".

[Jaimecbr900]

I have been a part in huge debates about this subject and the advantages/disadvantages of BBK's.

I have slotted front and slotted/drilled rears. When my rears need to be replaced, I'll do it with front matching slotted. I've never had issues with cracking in any of my rotors in any of my cars. I've ran them at tracks and especially in the mountains.

I've noticed that pads and size of the BBK's makes far more difference than if it's cross-drilled or not.

[Outphase]

Brembo blanks or Blanks of your choice...OEM size, and some nice pads like Hawk Pad HP+... and you're good to go.

[speedminded]

Brembo blanks or Blanks of your choice...OEM size, and some nice pads like Hawk Pad HP+... and you're good to go.

Maybe, but why not go all out if you have the sources to build a kit The Porsche calipers have 20% larger pads and going from a solid rotor to one that is 15% larger and vented. Steel braided lines, extended stud's, and spacing the wheels a several MM's (however much it takes to get the wheels to fit). Cheapest Brembo kit for my car is $2,400...I have a little more than 10% into it

[Outphase]

Definetly sounds good. Let me see your car. Haha.

[Outphase]

...wait a sec, I think I might have seen your car at mall of georgia once.

[speedminded]

...wait a sec, I think I might have seen your car at mall of georgia once.

doubt it...it rarely gets left out there...very rarely but it is possible.

Click the link in my sig...may have a mtn run this sunday too.

[Outphase]

doubt it...it rarely gets left out there...very rarely but it is possible.

Click the link in my sig...may have a mtn run this sunday too.

I'm not doing anything this sunday, where you headed to? I'd like to go.

[speedminded]

I'm not doing anything this sunday, where you headed to? I'd like to go.

Planned a mtn. run for next weekend but have a decent group wanting to go this weekend... http://forums.importatlanta.com/show...9#post34609039

[DrivenMind]

I had crossdrilled rotors on my Maxima, and didn't have an issue with cracking. But when I got the Corolla I went ahead and chose to go with Brembo blanks and Hawk Pads which work quite well on a 2200lbs car, shod with a sticky tyre.

[BLk92DA]

doubt it...it rarely gets left out there...very rarely but it is possible.

Click the link in my sig...may have a mtn run this sunday too.

lolz i seen you parked at D's driveway the other night haha...P.I.M.P

[speedminded]

lolz i seen you parked at D's driveway the other night haha...P.I.M.P

Shhhhh