Every once in a while we test a product on our race car. We use a lot of OEM parts especially when it comes to the brakes. I have tested drilled brake rotors and all of them have cracked within 15 minutes of on track duty. Keep in mind these are not monster Brembo's etc, these are stock diameter replacement rotors. We recently tried a set of Power Slot rotors and they were great! After 35 minutes of racing they have minimal wear, and a great surface pattern on them. The best part is they cost about the same as the OEM rotors. If anyone is interested in them let me know!

 

interesting. i was considering those rotors but went with OEM instead.
how does it compare to the OEM rotors in terms of pad wear?

 

We never really had a pad wear issue, the pads look like they havent even been used after 35 minutes of racing. The advantage of the slotted rotor is they let the gases from the pad escape, give the brake dust a place to go/keeping the pads cleaner. The only reason I made the decision to try them is they were the same price as OEM rotors.

 

You do realise that pad off-gassing isn't really an issue any more, right? Pad materials have progressed beyond the need for holes or slots, so why not just use OE type rotors? They can be had for really cheap from parts stores (~$100 for all 4), and many, many, many people run them without any quality problems. Even if the parts store rotors don't last as long, they're so cheap that it doesn't matter and it's still cheaper.

 

The really really cheap ones last about 5 minutes on the track before they warp (guess how I know). As for passing gas (lol) according to Hawk the pads do exactly that and that why the have a specific break in procedure etc. We used OEM rotors for 4 years and never had a problem, but I figured for the same price I would try slotted and see if we could get longer life out of pads and rotors. You have to realize there are 2 things you never try and scrimp on when racing-----TIRES AND BRAKES they can save your life.

 

did u use the powerslot drilled rotors or the sloted ones?
i've got slotted rotors and i've had them just over a year now with hawk hp+. the greatest thing about this set up is that the warmer the brakes get the better they work. they've worked AMAZING for weekly autoX but those are short runs. i'll try them out for lappign this year.

 

According to StopTech, rotors don't warp, what really happens is that the pads are leaving uneven deposits on the rotors, which leads to the pulsating pedal. Going to a higher temp pad should cure that issue. What the slotted or drilled rotors are really doing for you there is keeping the pad surface cleaner so that there's not as much chance of glazing and those uneven depostits.

As for bedding in what that's doing is getting a transfer layer of pad material onto the rotor so that the pads can work with adhesion, rather than by abrasion, which will help the pads and rotors last longer. Maybe Hawk's materials are old and out of date and still give off gas, I don't know, but it's pretty much universally regarded as a non-existent problem these days.

 

Well im not a scientist and dont want to get into a great debate about it. I see warped rotors on a daily basis at the dealership. When you put them on a brake lathe and spin them, its not a deposit you see. I have had 20+ years dealing in performance and have tried almost every brake combination you could think of. We have "over braked" a car etc. To answer another question about drilled rotors, I was given a set by a company to try on my Mustang at Shannonville a few years ago, they lasted 15 minutes before we saw heat cracks forming around the holes. I have seen heat cracking on many Porsches and other cars that come with drilled rotors. The rotors we tried were slotted and worked great. Like another person stated above the Hawk pads can be whatever technology they want......they work great! I have never had a failure, fad or anything using their pads.

 

01racing is right Rotors warp. Like himI have been in a dealership not his 20 + years, I bring 10+ years of experience. I have measured rotor runout, it exisits. Don't believe a rotor can warp, and it's glazing??? try this get your brakes hot, really hot and if you can make them glow do it, and while they are still really hot wash them in nice cold water and cool them off. Then Drive. What is that pulsation? Hrm, it's not glazing, I don't care how much you heat them it's warped.

As for slotted, I don't like them. Personal opinion. I think the slot is a waste of space. I used to run Hawk HP+ pads on Brembo blanks. Why? They worked and they worked good. The gas issues are gone with pads. Cross drilled rotors crack and break, I haven't got on to last yet...not true. All the nice pretty cars I have at work have them, I work for Pfaff and we have a very, very big racing background. Don't know Pfaff, look them up. They don't crack, why? Cuz Ceramic rotors are different. Porsche uses cross drilled, but one rotor on a 911 turbo is our entire brake system. It's not the same on the exotic cars. So don't use that to support cross drilleds. They are good for show only not performace.

As for the blank vs slotted, did you notice any stopping distance difference? I've never used slotted after all the trouble I had with cross drilleds I went right back to a good blank (my brembos never warped). The theory was more surface area more stopping power. I never had a gasing problem after I switched to the Hawk pads. I would have my rotors glowing red, smoke pissing out the wheels from the heat and still I could stop on a dime.

Oh and black91n/a - Hawk pads are actually a very good pad.

 

I am another racer with over 20 years of on track experience. I can tell you that brake rotors warp on race cars. I use aftermarket stock type rotors on my race FC. The rotors work very well with Hawk Blues. If I am not using the brakes really hard and keeping them in the operating temp range for the pad I am using, I get pad material build up. If I over cook the brakes, like in a 1 hour race at Shannonville, I warp the rotors. One time the rotors were so bad that they touched both sides of the caliper!!!! Talk about pad knock-back, LOL.

Regarding holes or slots, I haven't gone to the slotted rotor route yet on the race car. I have a belief that the slot or hole is a location for a stress riser that leads to a crack. I do recognize that there is a faster initial reaction to brake application using slots or holes. I think Al is correct in his application slotted work better. It all depends on temps and application cycle. Exactly why slotteds work better on initial application has been argued numerous times and I think that it is a vehicle/ race specific situation as to why the reaction time is better, but usually it is. Funny thing that in NASCAR at Martinsville, which is universally recognized as the hardest application for iron brake rotors, they use unslotted rotors. Hmmmmmm.........

Eric

 

Yes a slot will be a stress riser, it's not just an idea, it's a fact. It'll be much, much better than a drilled rotor for cracking (fewer and not all the way through), but nothing beats a plain surface. Miata guys amongst others swear by NAPA rotors for being cheap and being able to withstand any track beatings you can give them.

While Hawk pads are good, they're very hard on rotors, there's other pads out there that will stop just as well but won't be as hard on the rotors, although they're usually more expensive. I like my Porterfield R4's, and they even withstand some street driving (to and from the track) quite well.

 

I think the Nascar guys are not allowed to use slotted or drilled rotors, and if you look at the short track rotors they are a mile or so thick! (lol) All I meant by this post was to inform people that they the rotors didnt fail and performed well, and the price was extremely reasonable for a premium rotor. I have learned my lesson with 2nd and 3rd line parts, I would never put them on my or one of my friends cars. This was not intended to have the great brake debate as there are as many opinions as there are rotors.

 

Porterfield amazing pad. I would say better than Hawk, a bit more $$$ if I remember corectly

 

I certainly like my Porterfields, especially seeing as by reputation if I used Hawks, I might not have rotors by the time I get to the track, as I drive it to the track on the race brakes (not really time to change them once I get there). But yes, they are a little more expensive than Hawks, but if you don't have to replace rotors as often, then it could well be cheaper in the end anyway. From Mazdatrix a set of Porterfield R4 pads is ~$240, vs ~$210 for Hawk Blues at the cheapest place I've seen.

 

I need new brake rotors for my FD. Where do you guys buy yours?

 

I'd be interested in knowing where you got the power slot rotors. If I get brake fade on the Bruce County cruise again this year, the brakes are getting swapped for better ones.

 

We are dealers for Power Slot and Hawk pads. If you are using Hawk 9012 Blue compound you are absoluetly right about rotor wear. The Black compound or HP Plus should suffice for a street car on a lapping day. We dont even get the 9012 Blue compound hot enough in the race car at Mosport and have switched back to Black compound. Check out www.scarboromazdagarage.com in the parts section.

 

the Eunos 3 rotor u have in the rides section. just letting u know that rx7 specialties has imported 3 of them, they still have one that could use some body work.

 

Every year i go down to le mans @ mosport and see all the gt + cars with slotted rotors. Le mans is the pinnacle of Car racing IMO (excluding formula one), and if they (porsches, audi, vipers, vets, Austin’s, masseratti ((spelling))), are using them, they have to be doing something right. The enginieering staff behind each race team know their styuff in these particular fields, as i have spoken with a couple of them. They do serve a purpose, and are more effective for racing applications opposed to non tampered rotors.

 

And they use them....................................Once

 

i'm interested in getting new rotors and racing pads too. give me a pm

 

And they're probably ceramic or other exotic material. As well as oversized to hell and stopping a ~2000lb car.

Al, I'll be calling you about the rotors and pads and rubber as well.

 

Best track setup I find is brembo blanks (act of 75 cad each) and grandsport gs3. I tried hawk blue and black before. Both the hawks require more time to heat up (or don't work as well when not fully warmed up) as compared to the grandsport gs3 pads. The ebc yellows are good as well but the bite is not as strong as the gs3 or any of the hawks. However they (ebc yellow) are decent on cold rotors and still decent on hot rotors.

I cracked a pair of Napa economy rotors on the rx7 with hawk hp+ at dunville a few years back.

 

And they use them....................................Once
True, but they will endues more stress on to those rotors in 2 hrs more than you will in all likeliness in their entire life time.
ANd yes some cars are 2000LBs, but vipers are not quite as light as that.

 

You cant compare a $1,000,000 race car with ceramic rotors to anything on the street. If you look at Grand-Am cup the cars dont have drilled rotors. The Porshce street cars have drilled the race cars do not.................hmmmmmmmmmm