Pele

iTrader: (28)

So the forum decided to eat my post yesterday and I didn't have time to retype it. Retyping from memory...

Anyhow... Basically, in searching, I've seen people who love cross drilled and/or slotted rotors and people who think they're "About as useful/useless as **** on a boar hog"... (Can't find the thread that was in... Too lazy to search.)

Anyhow... I was wondering, is a rotor, a rotor, is a rotor? Is the $20 special at Advance Auto Parts/Pepboys/where ever the same rotor they charge $8000 for at the dealer? Are they the same rotors that came on the car 20+ years ago?

Is a rotor just a big round heavy thing that hurts like a ************ when you drop it on your foot, or are there differences in composition, metal type, internal vanes, size of vents, thicknesses, coatings/platings etc?

What makes crossdrilled/slotted rotors so useless? Aside from the fact the you can't put em on a lathe and turn em when they get warped... (Can you? It doesn't seem that you could.)

Mass to absorb heat versus lower rotating inertia and gas venting...

Anyhow... I'm trying to think of the most effective (best) brake setup that'll fit on the SE suspension... Stock caliper, caliper bracket, etc...

Now... Pads I know there's different compositions for friction material... Carbon/Kevlar, Semi metallic, ceramic, organic... Looking for something streetable... None of this need to heat up, doesn't work at low speeds, etc... The Hawk pads seem popular... What was it, Greens for racing, HPS+ for street?... Hmmm Gonna search more for that... If anyone has any input in that regard, please share it.

Rx-7Doctor

iTrader: (13)

Rotors play a major factor in stopping. I don't care for crossdrilled rotors but slotted allow
for better cooling by allowing heat to dissapate quicker. What you are looking for in an quaility rotor is th eamount of cooling fins they have, your economy have quite fewer fins versus something like napa's AE's made by division of raybestos, (for all that don't know, raybestos does not make their own brakes, a company called bpi makes them for them.
Napa's ae's are made of noise dampening iron and have the original amount of colling fins as determined gy the manufacture. The type of pad you need depends on what type of driving you do. Ceramic versus metallic, versus kevlar, etc. I have repco metal masters front and rear on myse and have over 70k on them. One thing i don't do is wait till the last minute to stop and i use my trans as it was designed for slowing down. Things to remember when doing brakes. 1). clean all parts with brake clean 2). lube all slliding components with
caliper grease, this is especially critical on the inboard pads which tend to ride against the rotor and prematurely wearout. If you dont have your rotors machined, either take 600 grit sandpaper and rough them up or use 3mmm roloc's with a drill to cross cut them. If you buy new ones clean them with warm soap and water before install. Dry them with white paper towels, not rags or blue towels, these have chemicals on them. Change the brake fluid every 30k or 2yrs. Do not overtighten your lugnuts, this will warp your rotors. After install they need to be burnished in. This means driving the car to about 30-35mph and applying
light to meduim pressure 15-20 times so the friction material bonds to the rotor. And you thought you have been doing it right all these years, lol. rx7doctor
w more

31rx7

From personal experience, the less expensive rotors tend to wear quicker and warp easier. On my ITA RX7, I only use Mazda OE rotors as I have not found an aftermarket brand that holds up as well. I also use Hawk Blue pads as they are very effective and last.

The way I look at brakes is based on how you will use them. My CSP autocross RX7 has NAPA rotors and AXXIS Metal Master pads. A fairly inexpensive setup, not exactly state of the art, but more than adequate. For street driving and autocross, this setup is more than adequate.

Where slotted / drilled rotors come into play is where you have repeated very hard braking, where there is not enough time between instances of hard braking to dissapate the heat buildup in the pads and rotor. If I can't induce fade with my ITA car with stock rotors and Hawk Blue pads, I seriously doubt that anyone on the street would need a more aggressive setup and need slotted / drilled rotors..

So, in my opinion, slotted / drilled rotors are a waste of money for street cars. They look cool, but are unnecessary.

There is more to it than this. For example, a lower effectiveness setup can be quite satisfactory if you run cheap tires. If you can lock up your Wal Mart specials with el cheapo pads and rotors, why would you need to go to better braking setup? Similarly, if your worn out suspension causes the front to dive under braking and overload the front tires, better rotors / pads won't mean a thing.

Start from the ground up based on your goals and usage with the car: Tires, brakes, suspension.

Give us some additional info as to what you are trying to accomplish with the car, and you'll get a reasonably definitive answer.

Suparslinc

Blanket statement: Don't buy anything made in China or Tiawan. I think mine were made in Canada, good Brembos are made in Italy (I think). All I have to offer

Pele

iTrader: (28)

Come to think of, I've seen a Brembo on display, cut open... They made reference to the inner channels adn vanes for venting having much more surface area exposed and having special contours or something... They weren't just straight vanes from front to center...

Advertizing gimmick or not?

My goal is a car I can run around in daily during the summer, but also I wanna take it up to Summit Point on the weekends for fun... Maybe join the local SCCA chapter...

I need some place to drive aggressively where I won't keep getting tickets.

LongDuck

I can already see a lot of naysayers on the cross-drilled and/or slotted rotors controversy, so I'll throw in my 2c on what my use was for my car, and how I upgraded the brakes accordingly.

First off, this is my daily driver. I want it to go fast enough for comfortable cruising on the streets and freeways, and stop fast enough during panic stops during city driving - I don't race SCCA anymore, and street racing is for fools. In Phoenix, AZ, the daytime summer temperatures are at or above 110F most of the time, so there is very little heat transfer capability in the ambient air temperature - this means that tires stick really well to hot asphalt and roadways, and tires tend to wear quickly due to hot rubber.

For this reason, I was easily able to fade the stock brake pads (Mazda factory pads) and stock rotors - this feels very scary if you ever have to panic stop and can't get the pedal to bite enough to slow the car adequately. After getting cut off on the freeway and having this happen, 1) I leave a lot more braking room now, and 2) I upgraded my brake components.

On top of this, larger wheels and tires usually weigh more than stock, increasing the rotational inertia that the brakes must overcome. Higher performance tires increase traction, allow for better braking force, albeit at a cost of increased brake component temperature. Installation of SS brake lines decreases fluid compliance, which can also put more pressure on your brakes. In all, brake upgrades need to happen in concert with other performance modifications that you make - it is a system that everything has to work together to function correctly.

That said; I use cross-drilled brake rotors (vented) at all 4 corners (SE suspension has vented rears as well), because of the high summertime temperatures that my car routinely encounters. I have matched these with Hawk HP+ (Race) pads, but will never buy these again due to excessive noise and excessive dusting. Next time will be Hawk HPS for street use SS lines have been installed after having one blow out on my Q45 a few years ago - mostly for durability. My decision for cross-drilled rotors was around the ability to vent the pad gases which build up and can cause brake performance loss. Slotted rotors don't cool the pads any at all, they simply scrape the pads clear with each pass, helping to keep fresh brake compound against the rotor. They are marginally effective at removing water from the interface if you live in a rainy state - I don't. Slotted rotors will increase the rate of pad erosion, however.

For me, Cross-Drilled rotors were a simple and effective purchase when considering replacement of my stock rotors which were worn after 175k mi of use. Internal venting is primarily a sales issue, since the centrifugal force generated by the airflow when the wheel turns will be limited by the inlet area which is constant between manufacturers (with un-drilled rotor designs). Once you drill those rotors, the ability for them to pass air and thereby cool the rotor surface goes up.

There is an argument to be made for metal mass that is reduced through cross-drilling, but in my estimation, the temperature loss through additional surface area (holes) is better than retained heat that then causes problems due to ambient air temperature being so high here in the desert. If you're that concerned about lost mass, put conductive grease (like heatsink compound) on your rotors where they meet the wheels and you can use your wheels as additional heat sink area (aluminum).

In all, you get what you pay for. I would go this route again if I had to, since brake feel is much improved and I get the added benefit of nice looking cadmium plated rotors to match my machined finish wheels. Go with what your budget will allow, but be reminded that braking is determined by tire contact patch and abrasion to the road surface, not by brake rotors, cross-drilling, slotting, or pads. HTH,

bouis

Forget cross-drilling and slotting: I had my rotors dipped in snake oil before I put them on -- not that it does anything, but how many people can say their rotors were dipped in snake oil?

As for cheap vs. expensive, I'd like to say that you get what you pay for but you really don't with these cars, since "cheap" rotors cost as much as the good ones for other cars. Go by the brand instead of the price.

Pele

iTrader: (28)

I am familiar with Raybestos/Raymold which we used extensively at the shop I used to work at... CarQuest rotors are Raybestos... I am also familiar wtih Brembo...

I know there's Bonez, available from Rotary Performance/RX7.com...

What other brands are there... I'm not sure if Bendix, Beck/Arnley, Borg/Warner, or Bosch make rotors at all, much less for the RX-7...