[blast1st]

Hi everyone i'm new to this forum and I have a question hoping you guys can help. im considering replacing my rotors and I want to do a cross drilled rotors. I want to combine it with OEM pads. is this a good combo? any info would be appreciated. thanks

 

[PrismKing]

No on the drilled rotors. They are far less reliable than solid rotors and are prone to cracking. The only advantage they offer is a bit more initial bite when wet as the water can recede into the holes. But they do not stay cooler than non-drilled rotors. The idea is that air flows thru them and provides an air cooled design, but there's no way to quantity it. Without air flow running thru them, they would actually cause the rotor to get hotter. The heat dissipation of the material used is higher than that of air.

If you want a performance rotor, get a slotted rotor. The slots provide an escape for the gas created during braking. They don't bite into the pad more, but they help to maintain a more solid grab between pads and rotor.

Direction on slots does not matter. What matters is the direction of the internal vanes of the rotor. If they are straight vaned, then you can put them on whichever side you want.

 

[blast1st]

No on the drilled rotors. They are far less reliable than solid rotors and are prone to cracking. The only advantage they offer is a bit more initial bite when wet as the water can recede into the holes. But they do not stay cooler than non-drilled rotors. The idea is that air flows thru them and provides an air cooled design, but there's no way to quantity it. Without air flow running thru them, they would actually cause the rotor to get hotter. The heat dissipation of the material used is higher than that of air.

If you want a performance rotor, get a slotted rotor. The slots provide an escape for the gas created during braking. They don't bite into the pad more, but they help to maintain a more solid grab between pads and rotor.

Direction on slots does not matter. What matters is the direction of the internal vanes of the rotor. If they are straight vaned, then you can put them on whichever side you want.

thanks for the info. what about the slotted cross drilled rotor combo? is that better or that will perform as cross drilled rotors as well? Thanks

 

[mrgold35]

I ended up going with HeelToe Stage II Brake upgrade (Racing Brake slotted rotors, braided brake lines, Carbotech 1521 pads) and Conti DWS 06 20" tires. The front rotors are slotted; but, also have vent holes within the slots. I've had this combo for +60,000 miles with no issues with warping, noise, or fade during extreme conditions (max load, +85mph hwy speeds, mountain switchbacks, etc...). The rotors are suppose to be good for 4-5 pad changes without the need to turn them. The rear Carbotech pads only lasted 30k and I switched them out with OEM pads. I'm still on the same Carbotech front pads and had 7mm all around when I did my last oil change at the dealership.

You might also think about upgrading your tires along with your brakes. The small contact patch on all four corners is the only thing that makes contact with the ground. A good set of tire along with brakes will help shorten the stopping distance and respond more quickly in panic situations.

Fronts:


Rears:

 

[blast1st]

^^^looks good mrgold35. I think im going that route as well. thanks

 

[75Blazer]

Here's a good read about rotor tech.

Rotors: Blank vs Cross Drilled vs Slotted and Warping | Automotive Thinker - Discussing the finer points of automobiles

 

[PrismKing]

thanks for the info. what about the slotted cross drilled rotor combo? is that better or that will perform as cross drilled rotors as well? Thanks

Well, drilled rotors don't perform any better then non-drilled rotors. The only mild advantage they have is if the rotors get wet, and that's only on the first time you use them. After you apply the brakes once or twice, they're dry.

The only reason that the combo rotors might be better than the rotors that are only drilled is that they probably have less holes drilled in them, so they aren't as weak. If you want to truly improve your braking performance, the solution is to install a larger brake kit. Larger diameter rotors increase your stopping power by giving the pads additional distance per rotation of the wheel. I don't know if anyone makes an aftermarket big brake kit for the MDX. You can always upgrade the rotors to a better material as well as get high performance brake pads. The pads will wear more quickly, but they will give you marginal improvement. I had EBC green stuff pads on my 850 R, paired with a 302mm brake kit and it was a good setup.

I do like the idea of using slotted rotors. They don't give you any additional bite, but they do minimize brake fade, especially under heavy and/or constant braking. Plus, you can always paint or coat the slots for a little bit of added contrast. You would be wise to use high temperature paint designed for use on headers and exhaust manifolds.

But yeah, don't waste your time with drilled rotors. You will be replacing them way sooner then you would have to replace a solid rotor. They look cool until you realize they are drilled solely for aesthetic purposes, but also give you worse performance.

 

[keith7120]

I have slotted/drilled rotors mainly for looks. My OEM rotors were warped. It seems like there is a lot more grip when braking from various speeds. Even after having them for about 4k miles. I have the Nakamodo brand.

 

[PrismKing]

I have slotted/drilled rotors mainly for looks. My OEM rotors were warped. It seems like there is a lot more grip when braking from various speeds. Even after having them for about 4k miles. I have the Nakamodo brand.

Well if you're comparing to warped rotors, then anything will give better grip. Warped rotors are a nightmare, not just by themselves, but the vibrations cause excessive wear to control arms, bushings, chassis components, and so on. Warped rotors are really a pain in the arse and they're enough to drive people like me completely mad.

If you're referring to grip as in braking power, the slots would account for some of that. The cross-drilling isn't giving you any measureable improvement versus a solid rotor, but the slots will definitely help, especially once the brakes get hot. Initial bite from cold brakes is always pretty solid, but once they heat up and stay at an elevated temperature, they lose bite because of the gas layer forming on the surface. Slots provide an escape for the gas, so you get better pad/rotor contact any time you apply the brakes.

The problem with drilled rotors isn't the fact that they don't improve performance, and the initial performance may be just as good, but they heat up more quickly, so the need for slots is even greater. This is, of course, assuming we're comparing rotors that are identical in material, vane geometry, size, vehicle, etc. You definitely want to torque your wheel bolts properly and check them every month or two. I've done a lot of research on warped rotors and while unevenly torque wheel bolts are the main cause, they don't usually warp to where there is measureable runout. The warpage is in the material itself and how it changes when it heats up. Hot spots and cold spots so to speak, which changes how it engages the brake pads. This is usually caused by a combination of heating and cooling paired with uneven pressure from the wheel bolts, and since they heat up more quickly, they're more prone to warpage as well as stress cracks (which will cause changes in shape and dimensions). Just my two cents on how to maintain them as well as possible.

 

[thumper]

any noise complaints from slotted rotors? i've been cautioned in the past about the edge of the pads clipping the slots as it turns which can result in noise...?

 

[mrgold35]

No issues with noise, fade, brake dust, or warping with my set-up after +65,000 miles.

 

[thumper]

No issues with noise, fade, brake dust, or warping with my set-up after +65,000 miles.

do you remember where you bought your stuff? i am looking to buy. i googled and this was all that came up... not sure if this is the only source:

https://www.heeltoeauto.com/uncategorized/stoptech-street-kit-slt-f-r-hon-934.40015-sto.934.40015.html

just looking for pads and rotors no lines

 

[mrgold35]

I did Heeltoe also for my MDX brake upgrade (HT-Spec Brake Package: Stage 2 Sport Package, 07-13 MDX): https://www.heeltoeauto.com/ht-spec-brake-package-stage-2-sport-package-2007-13-acura-mdx-yd2.html

Honda Genuine Brake Fluid, 2 Pints
Carbotech 1521 Front Pad Set (same front pads after +65,000 miles)
Carbotech 1521 Rear Pad Set (rears wore and replaced with OEM pads after 30K. Haven't felt a real difference with OEM pads in rear)
RB Performance UP Front Open-Slot Rotor Set
Replacement Rear slotted Rotor Set
Fastline Performance Steel Braided Brake Lines


I added the optional rear slotted rotors for $984 final price.

 

[PrismKing]

any noise complaints from slotted rotors? i've been cautioned in the past about the edge of the pads clipping the slots as it turns which can result in noise...?

Never heard of that in my life. The slots don't grab the pads any more than a plain rotor. The edge of the pad doesn't dip into the slot, nor are the edges of the slots raised. They just allow the gas to escape so the pad can maintain a more consistent contact with the rotor.

 

[thumper]

Never heard of that in my life. The slots don't grab the pads any more than a plain rotor. The edge of the pad doesn't dip into the slot, nor are the edges of the slots raised. They just allow the gas to escape so the pad can maintain a more consistent contact with the rotor.

from google:

https://www.google.ca/search?q=slotted+rotors+clicking+noise&oq=slotted+rotors+no&aqs=chrome.4.0j69i57j0l4.8855j0j7&sourceid=chrome&ie=UTF-8

 

[keith7120]

Again, I changed mine to slotted/drilled for looks. I'm not racing my MDX so the wear and tear should be about the same as a solid disc.

 

[thumper]

Again, I changed mine to slotted/drilled for looks. I'm not racing my MDX so the wear and tear should be about the same as a solid disc.

looks are not a big thing for me, except for rust. just tired at throwing money away getting these stupid oem rotors machined over and over again.

 

[PrismKing]

from google:

https://www.google.ca/search?q=slotted+rotors+clicking+noise&oq=slotted+rotors+no&aqs=chrome.4.0j69i57j0l4.8855j0j7&sourceid=chrome&ie=UTF-8

I've had slotted and drilled/slotted and neither ever produced any audible clicking sound. If the rotors are properly turned after the slots are milled, there should be no raised edges. Who knows, maybe the gas escaping makes a noise but it never happened with my setups. If there was a bit of a lip, a light chamfer on the edges of the slots would cure the issue immediately. If/when I replace the ruptures on mine, I might run high end slotted rotors on the front, but I certainly won't use drilled rotors. I'd rather get a big brake kit and use solid rotors though.

 

[PrismKing]

*rotors not ruptures lol