Excelerate

iTrader: (1)

There has been a lot of discussion as to whether slotted rotors or slotted/drilled (combination) rotors perform better. I am quoting ROTORA's newest press release on their site to give evidence as to what brake specialists believe. If you go to www.rotora.com and go to the first press release about the Toyota Scion, you will open a PDF file which on the second page says this,

"SLOTTED DISC: For heavy track use, slotted is preferred. For SUV and truck applications, slotted is preferred.

SLOTTED AND DRILLED DISC: For aesthetic and light track use, combination disc is preferred."

Aesthetic use means that it has to do with looking good, i.e. beauty.

This is not to say that drilled rotors do not provide performance since even ROTORA makes a drilled and slotted BBK, but in the case of performance rotors the drilling gives no more performance above the slots. The rotors are already slotted so any drilling is merely for aesthetics.

Red-CL

I always thought it was the opposite.

berny

thanks for the tip excellerate. I'm getting on the group buy for the rotoras

fuzzy02CLS

iTrader: (2)

It's true for SUV's & trucks. Slotted rotors perform better. I just ordered a set of these for my Explorer:

http://member.newsguy.com/~nutech/frames.html

proaudio22

The slotting was designed for letting the gasses escape that built up. However, it's been my understanding from the large brake companies that the pads that we use on the street no longer expell these gasses, so the slotting is moot. The only thing I could find that it helps is to keep a smooth pad surface, as it basically shaves the outer surface of the pad off every time you stop.

Drilling is what I found to be most effective, as it is just another aid to help cool the rotor. Notice on all the Ferrari's, Porche's, etc - what kind of rotors do they have? Drilled. However, our cars don't have the same cooling ducts those cars do, do there isn't the same cross flow cooling happening. Drilling can make a rotor more prone to crack under extreme heat, so proper cooling is needed. As long as that cooling is there, the drilled holes will help.

I found lots of info supporting solid rotors (well vented still) on street cars that aren't setup for additional cooling. They are less brittle, and provide more surface area for the smaller pads to grab onto.

blader

I think when done right and made for the braking system, slotted\drilled can be of benefit. Because come on, you can't tell me Porsche and Ferrari don't know what they are doing .. and they have drilled\slotted brakes on some models.

Although you cant go wrong with the slots. My front\rear set of Rotoras from the group buy will be here tomorrow with a set of axxis ultimate pads. Then ordering a UR crank pulley and off to the dealer for install

I can see this already turning into a flame war.

JakeCL

ive read somewhere else that the slots make the pads bite more giving improved braking but reduced pad life

Louie11

blader, Did you ever own slotted rotors before. They do work better and you will enjoy the better braking, but be fore warned that they do make an annoying noise compared to just drilled rotors. It sounds like a rattle snake. It's when the slots pass the pad even when not braking, but all the time. After time the sound lessens, but at first my friend was able to here it from his porch as I went by.

blader

Louie, no I've never had them before. What brand rotors\pads did you have and on what car?

Can anyone else with the Rotoras\axxis pads confirm this "rattlesnake" noise? I know some of you guys have them already.

dj5

I have the Rotora slotted rotors on both front and back with Axxis pads. There is absolutly no more noise than stock. No "rattlesnake" noise.

blader

Thank you DJ, that is great to hear, and thats what I thought the answer would be

I will have the exact same setup. rotora slotted front\rear and axxis pads.

evilstorm

not getting slotted/drilled?

blader

/\ No. Drilled is too controversial for me .. lol Not to mention more money and from what I've heard on here from people who's opinions I trust, its nothing but cosmetic differences with the drills.

evilstorm

i think its $16 more per rotor...not too much and worth it as long it doesnt crack or somethin..

Bluto

Done right, I believe the holes are cast in the rotor mold, not drilled after casting. The rotors are also much larger to maintain any surface area lost to holes.

Their brake systems alone probably cost more than our cars.


I have the Rotora slotted and Acura pads. I didn't buy the Rotora because they were slotted, I bought them because they aren't Acura's warp-a-lot rotors.

blader

16$ more per rotor, times 4 = 64$ more

How can you say its worth it. Your not even positive it won't crack .. "as long as it doesnt crack"

I think I'll pass. Slots are the safe bet and from what I heard, the way to go

JakeCL

most of the ones that crack are drilled after they leave their manufacturer, drilled by a 3rd party, the rotoras in the group buy are drilled by rotora

JakeCL

why would they be called "cross drilled" if the holes were cast?

blader

Why doesnt someone find out how Porsche does them, cast or drilled, I'm sure with their racing experience they know what they are doing.

blader

OK, I did some research on my own. Porsche casts their holes into their brakes. One site I read said it had something to do with removing water from the rotor better in the rain? I dont know how true that is.

Apparently holes that are cast into the rotor make a much stronger rotor than holes that are drilled after the fact. Pretty much everywhere I read said that drilled rotors will crack almost guaranteed in time, and only show benfit on "carbon" braking systems. It also said that Porsche rotors are ceramic .. I dont know what difference this makes though. All said that the slots are beneficial. Also saw a few pics of porsche racecars with large rotors that were JUST slotted, not drilled.

One site read that porsche started drilling their brakes in the 60s for uphill climb races, because it was less weight, but it was never intended to be used permanently. It also said that they would throw the rotors out after every race because they would crack pretty much every time.

Also read on one site that the reason Ferrari drills their brakes is to look good and so that they can charge alot for replacements But I dont think that is true.

Louie11

I have EBC's slotted and dimpled rotors. When I was at the track when I first got them I approached two other drivers with slotted rotors one was driving a mustang and the other was a GTP. they both said they had the same sound. I don't know what brand they had. When I called EBC when I first heard it, they said it was normal. May be ROTORA has a better set up I just wanted to give you a heads up since I thought this was the norm for slotted rotors.

JakeCL

whatever the reason i like mine

Try to ignore the curb rash

Rod

I'm also going for the slotted rotors. The cross-drilled rotors look great but since all the people who tend to give the best advice on this forum say that they're not going to do anything for performance I'll save the extra cash. And I really don't want to increase the chances of cracking the rotors, I want my new rotors to last me until the 100K mile mark when I plan on getting rid of the car. Plus Dave Hill even states the cross-drilled rotors available on the C6 are for aesthetics only.

Rod

That's basically why I'm going with Rotoras too, since the Brembo blanks are really no better than stock and the Rotoras seem to be the next best value.
How do you like the setup you have and how long have you had it? I'm getting Rotoras but am still undecided on the pads?

berny

Bluto, I'm gonna have the exact same setup. Are you experiencing any problems? How long have you have you had that setup for?

Bluto

I bought the front and rear Rotora rotors, front and rear Acura pads. Weird thing, the rear pads are made in Japan, front USA.

I only have done the front rotors and pads, about 800 miles ago. 56k on my car. Basically sounds and feels like stock. They may bite a little sooner. There is a screw that holds on the front rotors. I had to use an impact screwdriver to get them off.

I have not done the rear yet. They are not as worn, and not showing any warpping. I'll do them this winter, too hot in my garage to mess with now.

I don't do any agressive driving, nor do I have a rough commute, or hit a lot of traffic (frequent 70 - 0 braking). I stayed with the Acura pads, less dust, good quality, take the heat OK. They came with packets of anti-squeal grease.

I also changed the brake fluid. I used Honda, but next time I'll use Castrol. The fluid looked bad at 56k. I may do it every 30-40k from now on.

NiteQwill

JakeCL: Did you ever know that your rotors are facing the wrong direction? Slots are supposed to sweep inward moving from the center of the rotor to the perimeter.

As for crossdrilled v. casted holes, it's all structural integrity and tolerance. Decreasing mass, IMHO, invites heat to linger and cracks to occur.

Porsche has a ceramic brake system (which you can get aftermarket for close to $10K...), it's basically the superman of brakes because they do not warp, keep temps low, and need no rotation or resurfacing. Can be had OEM on the current GT3.

Bluto

Mine face the same way as Jake's, the boxes were marked R and L.

So does Smitty's Rotora BBK (pic 46):

http://imageevent.com/smitty/2003acuracls


Did Rotora mark the boes wrong

proaudio22

Your slots are facing the correct way. The slots should face what looks to be the opposite direction of rotation. This is to keep material buildup out of the bottom of the slot if it were to face the other way, which can cause shaking b.c of the unbalance of the rotor.

The most important aspect is that the internal cooling vanes face the proper direction. A good set of rotors will then have the slots faced in the what looks like opposite direction.

Internal Vanes:


External Slots:

NiteQwill

The theory that was popular for a while was to have the inside edge of the slot hit first and sweep outward. This helps remove the spent pad material, from the rotor. It was thought/observed in some cases where the slot swept outside in that the pad material would build up near the hub and cause a pulsating pedal. So, in that case, follow the manufacturers directions.

If the rotor has curved vanes in the center, make sure they are set correctly. This is not usually an issue since most slotted rotors for our cars are just straight vaned rotors and can run either way.

NiteQwill

Do you want to dissipate dust toward your hub or into the atmosphere?

JakeCL

the boxes the rotors came in were labeled right and left, so unless rotora is trying to play a creuel joke im pretty sure they are on right

NiteQwill

More info: http://www.stoptech.com/faq/data/faq16.html

NiteQwill

Do the vanes of the rotor face forward or backward on the Rotora rotors? Vane direction is the key to knowing the proper direction. Vanes should sweep inward to outward to produce a vacuum effect.

NiteQwill

I stand corrected, yes, unless Rotora is using that design, the rotors are facing the right direction

CleanCL

iTrader: (4)

I have used slotted rotors and upgraded brake pads on 2 different cars, both just street driving, with occasional harsh driving (no track). Perform brilliantly, great stopping, no problems.