Drilled and slotted rotors, all show and no performance?

[tekung89]

been looking into a brake upgrade for the dc2 but a 5studd conversion isnt within my budget. so i decided to look into the slotted and drilled rotors only to find they do very little. oem brakes are fine right now because the cars completely stock but like all car enthusiast, the car will undergo some changes through time and i would like to upgrade the brakes.

from wat i read they are purely cosmetic, its said that drilled and slotted rotors allow gases that build up during braking to escape quicker and reduces brake dust that ur rims collect during tracking or ever day driving.

and obviously there are those who debate and say they do provide better braking. and others reckon the only real brake upgrade is larger rotors because the increase of the larger surface area along with some good brake pads.

is anyone on this forum running slotted or drilled , or both? can someone give their 2cents :wave:

[Sp00ny]

I upgraded from a completely stock setup in my DC2 (Non-R) to...

DBA 4000 Series Slotted Rotors
EBC Green Stuff Pads

Front and Rear and immediently noticed a differance. Iv'e never really put them too the test on a track or done any really hard driving, however on the street the stopping distance and fade was noticably reduced.

If you really want to see how much differance a new disk/pad combo can make, check this out...

http://www.youtube.com/watch?v=f79EesoDj3U

and Don't laugh at the smoke, brakes really do do that quite easily lol. Good brake fluid helps this with a higher dry "boiling point" to transfer heat better and reduce fade.

With pads/disks you will notice better longetivety in braking force and less prone to fade...not so much straight out performance...

Contributors to Braking Force:
- Total Surface Area (Size of Disk/pad contact area)
- Pad Friction Co-efficient ("Bite of the pad")
- Braking Force (Caliper, pressure of braking system)

Contributors to Premature Fade:
- Incorrect temperature range pads, for application
- Poor Quality Brake Fluid
- Air/fault in brake system

Soon i will be upgrading to Endless SSS Pads & Motul Brake Fluid....will let you know how it goes...

Also remember the only way your going to get big braking performance gains....is by upgrading Caliper/Disks/Pads/Lines. Remember there is no point in having Endless 6-Pot Front Brakes if your tyres arent up to the task...once you build up one thing in your car, another will limit your upgrade....cars are such a money pit xD

Regards,
Andrew

[chargeR]

I have seen respectable brand name cross drilled rotors crack directly through one of the holes at the track. I have not personally seen this with solely slotted rotors, although I am not the most observant sort :).

If you wish to improve your braking performance, and keep in mind that nothing will improve your stopping distance if your tyres are not up to the task, I would carefully select a quality pad with a compound suited to your use and flush your brake system with a good fluid. By braking performance I mean consistency and feel, I am already assuming your braking system has sufficient power to lock up your tyres and hence enough power to stop the car in the minimum distance the tyres will allow.

I am using DBA slotted rotors at the moment, and I noticed no difference when fitting them that could not have been accounted for by fresh fluid and pads. I got them because I am a ricer. At the track though they create a nice pattern of spots of brake dust on the inner barrel of my white wheels exactly where the slots pass out of the brake pad area so the claim of slots aiding in evacuating brake dust and gasses has some merit.

[aaronng]

Most brands that do drilled might have a statement saying that they are for street use only. If you want to push your car hard, go for slotted or just plain blanks. The pads make more of a difference than the rotors. But the slotted rotor can help delay brake fade by skimming off the surface of the pad (but increases pad wear slightly)

[VTECMACHINE]

I don't know if I noticed a difference because of the slots... but I did change rotor compound. It's important that the type of material of the pad and rotor to match up. (ie Carbon ceramic pad, or carbon ceramic disk). The 2 materials bite harder together.

Since my new set up, I have noticed less brake fade. But that's most likely because of the NEO racing fluid I use, and braided brake lines.

Some people say that slotted rotors aren't as good, as you are loosing surface area on the rotor - which makes sense. But I doubt it's THAT noticable, unless you are a race car driver or something.

I wouldn't use drilled rotors, as I have seen a few snap, crack and even shatter. I still am yet to see that happen to a slotted rotor.

But as the oh so noble ChargeR states... Tyres are definately more important.
But... IMHO...If you want to play around with your brakes... try out a good brake fluid flush first. The try a good set of Pads first. Then Braided lines. Then Rotors... then calipers. Then Master Brake Cylinder.

[dsp26]

oh and braided brake lines combined with a master brake cylinder stopper :thumbsup:

[EKVTIR-T]

It's a well known problem..
Stick with slotted,nice higher temp pad and fluid etc..
http://farm1.static.flickr.com/241/521440634_60a2fdb88c.jpg?v=0
http://www.modbargains.com/images/Products/Power%20Slot/cracked_rotor.jpg
http://www.wam.umd.edu/~greghess/rotor2.jpg
http://www.stillensucks.com/FYI_stuff/cracked_rotor.jpg

[mooshie]

The latest seems to be dimpled rotors, well, it has been around for a long time but seems to be more and more companies rolling this out. personally I can only see this doing the same thing as the slots, But I am keen on a set of 300mm Wilwoods for my car that have this, only because they do not seem to offer the rotors in just plain slotted. Must do some more investigating, but it would stop the issue of cracking from being drilled right through.

[bennjamin]

hmm. ill add something.

do bikes and scooter brake discs simply not absorb and dissipate as much heat as cars ?
they are all crossdrilled and never crack.
Weight is also a factor !

[GreekWarrior]

the mass and velocity of the object your trying to slow down ultimately determines how much kinetic energy is transferred to the brakes.

[tekung89]

yeh i've heard many stories about drilled rotors being the ones that tend to crack, but maybe this happens because the rotor is worn out? or quality issue?

[aaronng]

http://www.mazda6tech.com/images/brake/crackedrotor.jpg

[jdm_kid]

http://www.mazda6tech.com/images/brake/crackedrotor.jpg

fail. lol

[A-man]

i dont think it is a issue of quality because brembo is bad for it it may be just to many close holes...


its very common for fords with the brembo brake upgrades to have cracks in the rotors

but look at the car its HUGE and there brembo rotors aswell... however those brakes to work better then the car with out the upgrade...

[Fuzz21]

my mate has slotted and dimpled in stead of cross drilled. made by rda with ebc red stuff
and he loves them. he was also told that the dimpled wont crack bcoz its not drilled the hole way thru. will post some pics soon

[A-man]

thats a good thereoy but i dnt think it would remove brake dust and water/ sand etc. as well as drilled

[aaronng]

thats a good thereoy but i dnt think it would remove brake dust and water/ sand etc. as well as drilled

Huh??? All you need is slotted. Water is not an issue.
You only need cross drilled for:
1) Looks
2) If you are using old-school asbestos pads which outgas.

Even DBA has a disclaimer for their 4000 series (1-piece motorsport level discs) that the cross drilled discs are for street use only.

[VTECMACHINE]

How about some photos of ANY rotor that has snapped, cracked or shattered. Would like to see one..........

Well, some have been supplied. But I can take pics of my slotted Project Mu rotors that have hair line cracks in them. If you brake hard enough..., and heat up the disks enough... when they cool down... they WILL crack!

[NSPYRE]

i dont think it is a issue of quality because brembo is bad for it it may be just to many close holes...


its very common for fords with the brembo brake upgrades to have cracks in the rotors

but look at the car its HUGE and there brembo rotors aswell... however those brakes to work better then the car with out the upgrade...

are u referring to eBay brembo's? sure, they are packaged in real brembo packaging and are real brembo rotors.... once. the sellers buy blank brembo rotors and have them drilled/slotted by a third party thus reducing the structural rigidity and they're being used the way they weren't intended to be

[bennjamin]

are u referring to eBay brembo's? sure, they are packaged in real brembo packaging and are real brembo rotors.... once. the sellers buy blank brembo rotors and have them drilled/slotted by a third party thus reducing the structural rigidity and they're being used the way they weren't intended to be

true that...kind of like drilling a hole or marking a cut on a cars suspension spring. will still work but wont last as long.

[A-man]

no im talking bout the BS expensive ones that ford sell.. that ive seen crack


i was looking at those brembo ones on ebay and was considering gettin them for my car.......


not so much water more so oil and whatever... i sorta just generalised..

[NSPYRE]

not taking biases here, but brembo aren't a cheap taiwan made brake rotor. they're used on some of the most high performace euro's cars money can buy. brembo is careful about the pattern it uses to drill the holes. they're not too close to each other, or to the internal vanes, so as not to sacrifice structural rigidity. the holes are also chamfered to relieve stress that sharp edges would cause

[Sp00ny]

not taking biases here, but brembo aren't a cheap taiwan made brake rotor. they're used on some of the most high performace euro's cars money can buy. brembo is careful about the pattern it uses to drill the holes. they're not too close to each other, or to the internal vanes, so as not to sacrifice structural rigidity. the holes are also chamfered to relieve stress that sharp edges would cause

I would probebly look at Brembo / Endless as amung the best mainstream brake system developers to this date....I agree they wouldnt just crack...They would be engineered to be sufficiently strong even if they are cross drilled.

Also Brembo are pretty much on every half decent performance car available.

Just A few:
- WRX STi
- EVO IV and above
- JDM DC5R
- Porsche's
- FPV
- BMW
blah blah blah with a list like this with companies that use their products as OE, i would trust their cross-drilled rotors without thinking twice ;)

[VTECMACHINE]

Guys... if you brake hard enough... and get the rotor hot enough, enough times... I can gaurentee the rotor will crack... EVENTUALLY! Not so easy with our light Hondas, but still they will crack eventually.

If rotors are for the street... DBA and RDA brakes rotors are more than enough. If it for the track, then yeah Endless, project Mu, Brembo etc should be looked at.. IMHO that is.

[JasonGilholme]

slotted are just fine for street. no cracking problems at all.

if you're after more stopping power consider your fluid and pad choice first before changing disc. If you want to upgrade further then slotted, i'd go to slotted/dimpled. more then enough for a slow ass, lightweight street honda.

[BusterSonic12]

Planning to get the DBA 4000 slotted rotors for my dc5R with the clubitr groupbuy. My car is mainly for daily street and just track it occasionally like 4 times a year. It doesn't look too expensive so i think i will give them a go.

I'm using Endless Type R pads for the front and stock for the rear. Will it be fine if i just upgraded the rotors on the front n leave the rear stock with stock pads?

[Zdster]

I would probebly look at Brembo / Endless as amung the best mainstream brake system developers to this date....I agree they wouldnt just crack...They would be engineered to be sufficiently strong even if they are cross drilled.


Most of the drilled rotors however are not drilled by Brembo. They are sold by Brembo as blanks (ie not slotted or drilled) and a third party purchases them and machines them. They are then sold on as slotted/drilled Brembo discs.

As stated by many others already, slotted are fine enough. There is no need to go to drilled unless you are purely in it for cosmetics and even then look to eventually replace them when they crack.

[NSPYRE]

Most of the drilled rotors however are not drilled by Brembo. They are sold by Brembo as blanks (ie not slotted or drilled) and a third party purchases them and machines them. They are then sold on as slotted/drilled Brembo discs.


are u referring to eBay brembo's? sure, they are packaged in real brembo packaging and are real brembo rotors.... once. the sellers buy blank brembo rotors and have them drilled/slotted by a third party thus reducing the structural rigidity and they're being used the way they weren't intended to be

repost ftw :P

[VTECMACHINE]

I'm using Endless Type R pads for the front and stock for the rear. Will it be fine if i just upgraded the rotors on the front n leave the rear stock with stock pads?


Yes that's prefectly fine. You'll see that alot of Honda circuit cars (Or majority of Front engine cars) in Japan especially leave the rear brakes standard, as all the weight is on the front.

[fatboyz39]

Drilled and slotted are to help with cooling. If its a street car dont waste your money on slotted disc, just save for good pads.

[Sp00ny]

It's a well known problem..
Stick with slotted,nice higher temp pad and fluid etc..
http://farm1.static.flickr.com/241/521440634_60a2fdb88c.jpg?v=0
http://www.modbargains.com/images/Products/Power%20Slot/cracked_rotor.jpg
http://www.wam.umd.edu/~greghess/rotor2.jpg
http://www.stillensucks.com/FYI_stuff/cracked_rotor.jpg

I can't be 100% sure just by a picture but by the look of the grove in that disk...it looks like the disk was well past the minimum thickness (wear point) and that would cause a weaker disk and make it prone to cracking...

Just My $0.02 xD

[aaronng]

I can't be 100% sure just by a picture but by the look of the grove in that disk...it looks like the disk was well past the minimum thickness (wear point) and that would cause a weaker disk and make it prone to cracking...

Just My $0.02 xD

My solid discs look like that with the grooves, been to 5 trackdays and gets punished to slow down the 1400kg car, yet it hasn't cracked. Probably past minimum thickness too. :p

[Zdster]

From what I understand it is harder to machine a drilled disc as well. Can anyone confirm this?

[A-man]

it shouldnt matter it doesnt matter its ony cutting the surface... its harder on the pads because of what its made of but the machining bits r high tensile and it doesnt matter....



an update on my mates gtp i was sayin in a previous post... he changed his to slotted and dimpled and apparently were cheaper to i think...

[dsp26]

Yes that's prefectly fine. You'll see that alot of Honda circuit cars (Or majority of Front engine cars) in Japan especially leave the rear brakes standard, as all the weight is on the front.

i know this is off-topic but um... is that homers face on a vagina in ur avatar?? haha

[dsp26]

From what I understand it is harder to machine a drilled disc as well. Can anyone confirm this?

it is but for slotted.. it's coz its not a flat surface and the diamond tips or whatever that is used to do it gets damaged easier when falling into slots

[Sp00ny]

My solid discs look like that with the grooves, been to 5 trackdays and gets punished to slow down the 1400kg car, yet it hasn't cracked. Probably past minimum thickness too. :p

lol nice.

I was just saying as if your disks are past minimum thickness then this cracking issue is purely the owners fault. It does say minimum thickness for a reason xD lol.

[aaronng]

lol nice.

I was just saying as if your disks are past minimum thickness then this cracking issue is purely the owners fault. It does say minimum thickness for a reason xD lol.
If it is drilled or even slotted, then the disc has been weakened and is more prone to cracking. I'm just rebutting that the cracked disc in that pic was badly worn, and hence it cracked. I'm trying to prove that minimum thickness and grooving is not an indicator that those cracked discs were about to fail anyway.

When DBA says that their 4000 series is suitable for track only if you have the blanks or slotted, while the cross drilled are only for street, then you know something is up because the 4000 series are heat treated and are basically at the level of the sports rotors that you can get frmo Project Mu and similar.

I will measure my disc thickness later today and compare it to the service manual's minimum thickness spec at home tonight. :thumbsup:

[jugbugz]

I have slotted SPOON discs at the front... only thing I'm not happy with is the amount of brake dust i get after 1 day. :(

[pattyd89]

this is what a seller on ebay says:

Brembo OE "blank" rotors offer better performance than Cross-drilled rotors. Cross-drilled rotors might look "cool", but what are they really doing for performance? Brake rotors were first "drilled" in the 40's and 50's because early brake pad materials gave off gasses when heated to racing temperatures, which is called "gassing out". These gasses then formed a thin layer between the brake pad face and the rotor, effectively lowering the coefficient of friction. The "cross drilled" holes were implemented to give the gasses a place to escape. Today’s brake pad materials do not exhibit the same gassing out problems as these early (old) pads. Also, there are many companies that sell "cheap" cross-drilled and slotted rotors. They do this by purchasing Brembo blanks and having them cheaply altered by a third party. Doing this sacrifices the rotors structural integrity, and can be a huge safety risk. If you contact Brembo, they will not recognize these discs after they have been altered. These rotors are known to crack and warp very quickly. If you want the actual Brembo cross drilled and slotted rotors you will be paying much more. That's why these blanks are perfect; they perform better, do not tear through pads, are priced much lower, and are much safer.

[bennjamin]

another thought.

any drilled rotor has less effective surface area than a blank disc - so even if the material is far superior and will not crack , a blank rotor of the same surface area will always pull up better. someone expand on this for me my head hurts lol

its a big wank :)

[94dc2tegz]

to my understanding

blanks are always better than drilled/slotted because there is maximum surface area achieved and this is what you want with braking.

Although it could be argued that the massive amounts of heat generated and with no where to go this could be countered by the build up and eventual brake fade thus this is where drilled/slotted techniques can come save the day.

Although unless your seriously using your brakes and experiencing diminished braking power throughout say the track session then blanks are the way to go.

I guess it's similar to slicks - they have no tread - lets not mention they're a completely different compound all together - but they achieve the maximum static friction coefficient attainable limited to the width of the area in contact to the road.

This is way upgrading rotor's is better than just added bigger brakes/pads because there is a limit to how big or harsh the brake/pad combo you add as the rotor is only so big and the heat dissipation doesn't increase so your just hurting yourself even more in the long run.


Thats just what I think...

[A-man]

ur bang on the money there plus hydraulics works by excerting equal force upon the same surface so more area more braking

[VTECMACHINE]

I have slotted SPOON discs at the front... only thing I'm not happy with is the amount of brake dust i get after 1 day. :(

Sorry.. you have slotted OEM disks? Because that's what Spoon disks are. Slotted OEM rotors. Brake dust is generally associated with the type of Brake pad, not the rotor.

[l3vnd1]

Not necessarily the case;

If the pads are too harsh for the disc, they could eat away at the disc.

This causes grey brake dust which is a result of the disc being worn away.

This may be the case as what you say, (Spoon is just OEM), your brake pad might be too harsh for your disc.

I was under the impression that Spoon manufactures like OEM, however with a higher specification/tolerance.

An example is the Spoon engine mounts - same style, just stiffer rubber.

[dsp26]

ok this is good info so i'll give a scenario...

if a first timer went track day with the decent oem pads or slightly better.. assuming good fluids and braided brake lines.. would you get blank or slotteds?

not sure how great the honda range of pads are but even really good pads over gtir/nxr rotors sucked and only worked great with slotted due to brake fade....

[bennjamin]

BLANK

blankblankblankblankblank

[jugbugz]

Sorry.. you have slotted OEM disks? Because that's what Spoon disks are. Slotted OEM rotors. Brake dust is generally associated with the type of Brake pad, not the rotor.

Yeh what I was replying to was that slotted rotors chew off more brake pad which in turn makes more dust. :D

I didn't know they are same as Type R rotors. They look different up close though, unless its just a coat.

[EG30]

http://www.ozhonda.com/forum/showthread.php?t=90508&page=3

I posted my experience at a track tuning day with my brakes which are 262mm dc2 calipers with RDA slotted rotors.

The slots kept the rotors surface clean in my case, as you could see the friction residue got embedded in the slots themselves instead of depositing in patches on the rotors causing vibration and uneven friction issues.

I got them well over 500C and and you could see them glowing even in broad daylight! No signs of cracking on my rotors, but on grey cast rotors such as these once you get past 630C they'll start to crack even if non cross drilled. If you happen to get them up that temp range, cooling ducts are essential.

[Hullabaloo]

what about discs like this:
http://www.evo.co.uk/images/front_picture_library_UK/dir_34/car_photo_17039_25.jpg

(I would insert the picture, but photobucket it blocked at my workplace.)

[VTECMACHINE]

what about discs like this:
http://www.evo.co.uk/images/front_picture_library_UK/dir_34/car_photo_17039_25.jpg

(I would insert the picture, but photobucket it blocked at my workplace.)

They are fine. Similar to Slotted technology. These are called Dimpled rotors I think.

[Hullabaloo]

i thought these were called dimpled:
http://www.turboimport.com/catalog/rotors/rotor_ad.jpg

as for the rotors on that evo, they look like some cross between drilled and slotted since they go all the way through (unlike dimple drilled). Would they be as prone to cracking as standard drilled? depending on the number of "crescents" i imagine that that disc would have more surface area than a standard drilled yet still have some of the benefits of slotted and drilled?

[aaronng]

what about discs like this:
http://www.evo.co.uk/images/front_picture_library_UK/dir_34/car_photo_17039_25.jpg

(I would insert the picture, but photobucket it blocked at my workplace.)
If they are made properly and not your entry level crappy brand type, then they should be fine because JGTC cars use them too.

http://images.sportcompactcarweb.com/features/sccp_0809_09_z+honda_thank_you_day+honda_takata_do me_nsx.jpg

[VTECACCORD]

Yeh what I was replying to was that slotted rotors chew off more brake pad which in turn makes more dust. :D

I didn't know they are same as Type R rotors. They look different up close though, unless its just a coat.


Actually spoon discs weigh a lot less than OEM discs, so there no the same.



Cross drilling of conventional mass-produced brake rotors often leads to heat cracks and rotor failure. To solve this problem, Spoon undertook extensive research and design, eventually developing a flap-type, cast-metal rotor. A uniform distribution of carbon content in the metal maximizes heat resistance and manufacturing consistency between rotors. Holes are cast during the rotor casting process, rather than cross-drilled, providing superior strength and cooling performance. In comparison to stock rotors, these will resist and dissipate heat better, resist warpage and cracking better, last longer, and are lighter.



Features
- Manufactured from unique material featuring enhanced rust protection and strength
- The S2000 rotors features drilled rotors for enhanced cooling
- The S2000 front rotors weight reduced to 5.3kg from standard 6.47kg
- The S2000 rear rotors weight reduced to 4kg from standard 4.3kg
- The Integra DC2/DB8 calipers measure 300mm by 26mm thick