some say they break easily...others say its good to get...i am hoping someone out there can give me some experienced advise on wether or not i should purchase a set of cross drilled rotors for my 90 vert. do i need for both front and rears? is there a particular brand i should get? does anyone have any other suggestions? or places to buy them? should i only purchase for the rears? are they good for street use for my daily driving and occasional racing(not track racing).

Fred

 

Hi

That depends.
As for track racing, AP is the best !!
But very expensive.

Generally, USA made rotor rings are easy to crack.
We use wilwood or stoptech rotor rings for street.
It is reasonable.

You run mainly on the street, go for cross drilled one.
It is gooood looking.
I will post pics of my brake system.

Which manufacturer are you thinking of?

 

not really worth the cash. it is more for bling bling on a street car. there was a very heated debate in the 1st gen section on this if you want to run a search. unless you are going to upgrade to a big brake kit, i wouldn't worry about it. you aren't going to see any improvement in your application.

 

I also say get the cd rotors...They will work fine for the application you are gonna be driving, also you do not need rear cross drilled but you can get them....

 

Fine for the street. Not a good idea for the track IMHO.

PaulC

 

i say go with some powerstop cross drilled and slotted. i had some way back on my crx si and they worked well. not that expensive either

 

They will look cooler.
That is all.
Oh, and they will cost more and have a shorter life...

 

Im in the midst of finishing the 5 lug conv. and in a couple months I plan to switch to cross drilled fronts. Ive also heard about them cracking but I dont see any reason why they would if they're quality rotors. Not to mention the added cooling effects and a little more weight off then stock.

 

ahh good old cross drilled brakes...

history of them: they were made to release gases from gaseous pads.

why people buy them: hype and/or looks.

No matter the quality of the rotor, they will crack. Even rotors *cast* with holes will crack, even ones the expensive porsche ones.

Without going into a long long discussion, here's my experience and theory on brakes.

What rotors are best IMO: Non cross-drilled, non slotted (ie "blanks") for anything besides rally. For rally, slotted.

If you find a set of race pads from 1950, go cross drilled.

As for the light than stock comment, this is exactly what you do NOT want in a 1 piece rotor. Thermal mass is your FRIEND, not enemy. The more metal in the disc, the more heat it can hold. This is a *good* thing.

You will stop no shorter with these rotors, and after repeated stops they will cause fade due to the pads exceeding their max effective temps.

 

There are alot of debates on this subject. All I can say again, in regards to german cars, is that they do work. Here at work, I see all new Porsche have them.

One of the execs here just bought a new SL500. They come with clocked-drilled rotors also...if they are using them, why not!....

I'm actuall considering using the cross-drilled wave rotors. I have used them on my Gixx and I do like them. The only prob is just the inital brake pulsing.....

 

Oh...last thing. I believe that considering brake pad material is more important the clocked, drill, etc, rotors.

STOPPING IS WHAT COUNTS.

 

Have you ever looked at Porsche's *race cars* though? You'll notice that the street cars have x-drilled, but the race cars don't.

They market them solely as assiting to remove water from friction areas (pad/rotor surface).

 

Soo, i am hearing brembo fronts? does anyone have these cross drilled/slotted rotors actually on their cars? please give your input on price and i guess a place to buy them at a good price.

Fred

 

Brembo OEM Replacement Blanks front and rear-

x-drilling is NOT whats makes porches stop like crazy. The mono-block billet alluminum calipers and the 320mm+ rotors + bad *** pad compounds + badass ABS computers make porches stop fast + huge front meats make porches stop fast, not the bLiNg bLinG cross-casted holes (which are cast into the rotor on birth and chemically treated/cryo-treated to keep them from cracking so soon)

 

The more metal in the disc, the more heat it can hold but then the release of heat is slower then to a comparable cross drilled example. Cross drilled rotors may heat up more quickly then solid blank face rotors but they also shed that heat just as quickly.

 

"we dident notice any differece between X-drilled rotros Vs. normal rotors in normal conditons. But for some reason, they seemed to work better in the rain."
- Some Porsche racer guy i know.

I spoke with this guy about x-drilled rotors and he told me from his personal experence. He raced in a lot of porsche cups and so-on for many years. Last time i saw him he was campaigning a Porsche GT-3. Maybe they work better in the rain because of steam?

 

Sorry Nismo, but no.

90% of the cooling of the brakes is coming out of the venting surfaces between the two sides of the disc, far more surface area there than those tiny holes are going to provide.

Plus, you don't WANT them to cool down too fast anyway, sudden thermal changes is what WILL crack a rotor, regardless of x-drilled, slotted or flat. Plus most pads are designed to operate in a certain temperature range, go above that and they fade. Go below that and they wear the f*** out of the rotor..

But who cares.

99% of you aren't racing your cars.

You want crossdrilled rotors? Go for it. There's a chance they'll crack, but you're not using the brakes enough or getting them hot enough for thermal changes to really get the rotors to the point where cracking is a guaranteed thing.

BUT

Don't tell people they work better. They don't. These types of rotors were designed back when brake pad outgassing was a significant problem, and they drilled the rotors to keep the pads from floating on the layer of gas instead of against the rotor itself.

I think they look cool, but on my FC racer, bone stock Autozone rotors is what I use.

PaulC

 

Does anyone have a good source for the Brembo REAR stock replacements? The Tire Rack has the fronts, but they (Tire Rack representative) said Brembo doesn't have a rear disc, but of course, for just a little more money I could get Powerslot rotors.

 

brembo doesn't make front or rear rotors of FCs.

last time i checked they didn't.

also silkworm, is there any difference between say OEM Mazda blanks vs autozone/pepboys blanks?
or are they all the same?

 

Well, the Mazda blanks fit very tight up against the hub, which is why you need a hammer to get the f**kers off. Autozone's fit rather loosely. Other than that, I don't notice any other differences. They work fine at the track

PaulC

 

They make front ones according to Tire Rack. Go ahead and do a search at tirerack.com

I gurantee you you will yield results.

Jerry

 

Common misconception.

You want to dissipate as much heat from the PADS as possible. To do this, you need as much thermal mass as possible. Rotor cooling is done via vents in the center of the rotor as Silkworm said. We've made cooling ducts connected to custom plates that forces air through the vents on our road race car and have 0 fade problems with the tiny 1st gen brakes.

I can get shitloads of racers to come here and say the same thing, post quotes from AP's site, etc on their thoughts of x-drilled, etc. If you really want, I can go find those. Also links from brake engineers who know far more about it than most of us who will say the same thing.

Silkworm: Glad to see others that know brakes here as well :thumbup: and I rock autozone rotors too, love them on every application I've used them on.

Plus the three month warranty.. I can kill rotors in less time than that. :P

 

so the conclusion is to go with aftermaket OEM stuff? ie pep boys, napa? canadian tire etc... instead of mazda OEM stuff?

i need 4 new rotors, and my car will get the best i can buy. Since everyone keeps on saying slotted / x drilled suck or are good... i'll go with what works. blanks.

with hawk HP+

the question now is... do i splurge and use mazda stuff or canadian tire (ie pep boys) crap

 

Thanks for clearing up some of those misconceptions

 

I like Autozone rotors personally. We use them on everything, including the SCCA car. I used some rotors from discount before and it did't last too long (with Hawk Blues however). But the Autozone's with Blues last a lot longer.

Slotted is good for rally/offroad. But for street, blanks are perfect.

mmm hawk pads. love hawk brakes :P

well, for the price of one OEM Mazda rotor, you can probably buy multiple autozone/pep boys rotors, so even if they wont last quite as long...

I personally never use OEM rotors on any car, even new ones.

But, brakes are something that are very important, and having confidence in your brakes is even more important, so if Mazda OEM will give you more confidence in your brakes, then I'd get those no matter the extra costs.

Nismo: Sorry if I was harsh. I just take brakes a bit seriously since they are one of the more important systems in a vehicle IMO.