For those who have ACTUALLY USED BOTH... Is there any distinct advantage to slotted rotors for the race track?

I have been perfectly satisfied with my stock rotors with Hawk HP+ pads. Well, I could maybe use more pad now that I'm on R-comps, but the rotors are fine.

Is there any justification for the higher price of slotted rotors? I don't care at all about the looks. I know cross-drilled rotors can crack with track use, so I don't want those. Are slotted rotors succeptible to the same thing, or will they wear out faster?

Qquick responses would be appreciated, as I plan to order tomorrow
THANK YOU!!

You want a rotor with the most mass for performance and least brake fade.

The slotted rotors are for gassing, when the pads reach their operating temps or higher they start to gas or breakdown and the slots are there to allow the gas to escape.

however they are more prone to cracking... as opposed to a solid rotor.

Yeah, I know the function of a solid vs slotted rotor.

My question is whether anyone has experience with both and if they've experienced any differences with race track use.
HAS anyone had a slotted rotor crack during track use?
HAS anyone experienced more rapid wear on a slotted rotor during track use?

Thanks.

i had a crack develop in my stock rotor.

btw, 'solid rotor' means to me thats its not vented.

james

whether on the street or on the track... a slotted rotor will have a tendency to crack easier than the stock rotor.

Alright, guys. Thanks for the comments. And, yes, a "solid rotor" would be unvented. I should've said a "blank" rotor. I'm glad you knew what I meant.

Anyway, I ordered 2 full sets of HP+ pads and a full set of slotted rotors from www.rx7store.com. Jason hooked me up and I got a good deal on the package so it was a little cheaper than splitting my order to get stock rotors. It was still just over $600 with shipping! Although it was a good deal.... Ouch!
I'll probably put these slotted rotors on before the next track day and keep my stockers on hand (which are showing the results of hard use) as emergency replacements, just in case.

Thanks again, guys.

rx7store.com <-- closed out

Alright, guys. Thanks for the comments. And, yes, a "solid rotor" would be unvented. I should've said a "blank" rotor. I'm glad you knew what I meant.

Anyway, I ordered 2 full sets of HP+ pads and a full set of slotted rotors from www.rx7store.com. Jason hooked me up and I got a good deal on the package so it was a little cheaper than splitting my order to get stock rotors. It was still just over $600 with shipping! Although it was a good deal.... Ouch!
I'll probably put these slotted rotors on before the next track day and keep my stockers on hand (which are showing the results of hard use) as emergency replacements, just in case.

Thanks again, guys.

What signs of hard use are on your rotors? Cracks? Gouges/excessive wear?

rx7store.com <-- closed out

My bad... RX7Store.NET

What signs of hard use are on your rotors? Cracks? Gouges/excessive wear?

Blue coloration on the outer half of the rotors and light surface cracking (not functionally impeding).

i also have a heavily pulsating pedal (causes by uneven thickness of rotor resulting from uneven transfer layer) any slight imbalance will be greatly enhanced by heavy use/high heat.

james

Can you comment on HP+ noise level on the street? Another RX-8 buddy owns HP+ and
has yet to do the proper bed-in procedure. His car can be heard from 16 blocks away, LOL.
Wondering if the bed-in will cure the noise, or if it is to be expected due to the shift of
effective temperature range to higher level as compared to stock pad.

Stick with the stock discs. The slotted ones are good in theory but you're giving up contact area for minimal cooling advantage.

Can you comment on HP+ noise level on the street? Another RX-8 buddy owns HP+ and
has yet to do the proper bed-in procedure. His car can be heard from 16 blocks away, LOL.
Wondering if the bed-in will cure the noise, or if it is to be expected due to the shift of
effective temperature range to higher level as compared to stock pad.
I had HP+ on my 325is and they were fine. A little bit of sqeal on the street. Just enough where someone who doesn't know any better may say, "get your car fixed!". However, I took great satisfaction in knowing that it was because they were high performance :boink:

On the RX-8, though, they're REDICULOUSLY loud!! It's almost insane how loud they were. I didn't much care about it during the summer, between driving schools, but I swapped back to stock pads for the winter months. Now I think I'll mostly be swapping back and forth for the driving schools. The HP+ work awesome on street tires, though, and they're so (relatively) cheap. I go through a full set in 1 weekend at the track, so cheap is important. When I went to R-compound tires, I thought I could now use a little more pad. These are still adequate, though. With the slotted rotors, I think they should be perfectly adequate, still. Their initial bite is fantastic. Fade resistance is very good. I only got the slightest hint, on the R-comps, with several, several VERY hard laps.

Stick with the stock discs. The slotted ones are good in theory but you're giving up contact area for minimal cooling advantage.
Thanks, but too late. I got a good enough deal that it was cheaper to get everything from Jason at www.rx7store.net than to split my order (and pay more shipping).
Hopefully they'll be ok. I'll have my stockers with me as back-ups :p:

Just seeing this thread.

You will probably notice a big difference in the weight of the stock rotors and any aftermarket ones.

I have seen a slotted rotor crack on an RX~8 at the track....it is good to have a backup.

When I switched to the slotted rotors, I did the stainless lines, and switched to hawk HP Plus pads.

After bleeding them correctly, which was tricky, I noticed a huge difference in stopping power. Plus I had renewed confidence that I could brake harder, later at practically every corner....I switch the pads out sometimes, but often squeal around town. I like it that way.

Like everything else, marketing specs (slotted, plain, drilled, drilled and slotted, etc.) are spiffie advertising words. The meat of the matter is the quality of the materials (quality of steel), engineering done on the design, the quality of the manufacturing, dynamic balancing (if any) done, finishing and coating applied, heat treatment, etc., if any... that make the product either cheap and therefore appealing to some, or expensive, and therefore appealing to others. Then there are those products that are expensive, but made cheaply to maximize profit.

Blindly saying slotted is bad, plain face is bad or good, drilled will weaken the rotor, etc. will last longer, provides better braking, all these depend...that depends is the crux of the problem...and what you pay for... not the advertising words.

Caveat emptor, roughly - best to know exactly what you're buying and why you're paying what you are, or you will get something you might regret later.

I noticed a huge difference in stopping power. Plus I had renewed confidence that I could brake harder, later at practically every corner.Were you able to invoke ABS before you changed rotors? If so, then your stopping power was limited by tire traction, not your brakes. If that's the case, you may have noticed a huge difference in your brakes' "grabbiness", but you won't have experienced any improvement in actual stopping power.

Like everything else, marketing specs (slotted, plain, drilled, drilled and slotted, etc.) are spiffie advertising words. The meat of the matter is the quality of the materials (quality of steel), engineering done on the design, the quality of the manufacturing, dynamic balancing (if any) done, finishing and coating applied, heat treatment, etc., if any... that make the product either cheap and therefore appealing to some, or expensive, and therefore appealing to others. Then there are those products that are expensive, but made cheaply to maximize profit.

Blindly saying slotted is bad, plain face is bad or good, drilled will weaken the rotor, etc. will last longer, provides better braking, all these depend...that depends is the crux of the problem...and what you pay for... not the advertising words.

Caveat emptor, roughly - best to know exactly what you're buying and why you're paying what you are, or you will get something you might regret later.


:werd: :werd: :werd: well said Spin :)

drill & slot rotors are no use, just get some new stock rotors with some hawk blues, SS lines, and ford brake fluide.

Were you able to invoke ABS before you changed rotors? If so, then your stopping power was limited by tire traction, not your brakes. If that's the case, you may have noticed a huge difference in your brakes' "grabbiness", but you won't have experienced any improvement in actual stopping power.

Yeah, man. HP+ pads are soooo grabby. I love them for street tires. Now on R-Comps, I could use a little more aggressive pad, but I'm sticking with the HP+ cause they're so inexpensive.

Like everything else, marketing specs (slotted, plain, drilled, drilled and slotted, etc.) are spiffie advertising words. The meat of the matter is the quality of the materials (quality of steel), engineering done on the design, the quality of the manufacturing, dynamic balancing (if any) done, finishing and coating applied, heat treatment, etc., if any... that make the product either cheap and therefore appealing to some, or expensive, and therefore appealing to others. Then there are those products that are expensive, but made cheaply to maximize profit.

Blindly saying slotted is bad, plain face is bad or good, drilled will weaken the rotor, etc. will last longer, provides better braking, all these depend...that depends is the crux of the problem...and what you pay for... not the advertising words.

Caveat emptor, roughly - best to know exactly what you're buying and why you're paying what you are, or you will get something you might regret later.

True story. I have little to go on other than the brand reputation. I believe that these are Brembo, but I'm not sure. RX-7store.net. It says Brembo in the window header, but not in the description...

I got a little buildup on my slotted rotors, so I switched back to the OEM ones, but good either way.

I got a little buildup on my slotted rotors, so I switched back to the OEM ones, but good either way.

You were using them on the track, right?
What pads were you using? Which rotors did you buy (and from where)?
Did you ever try light sanding or using different pads, or something, to remove the build up?
What effect did the build up have?
Did you notice any difference in pad life?
Could I possibly ask any more questions?! :crazy:

Thanks!

I got a little buildup on my slotted rotors, so I switched back to the OEM ones, but good either way.


probably due to your pad choice; which brand pads did you use?

I was switching back and forth from the OEM ones and Hawk HP+

You were using them on the track, right?
What pads were you using? Which rotors did you buy (and from where)?
Did you ever try light sanding or using different pads, or something, to remove the build up?
What effect did the build up have?
Did you notice any difference in pad life?
Could I possibly ask any more questions?! :crazy:

Thanks!

Hawk HP+
StopTech slotted
No
Steering wheel shimmey under hard braking
No
Yes

Too easy to warp stock rotors. Haven't had that problem with slotted ones.

To me I can brake harder over more laps with the slots. I tell the cooling affect. there's less brake fad. But then again I brake hard and deep.

Also, go with Cermaic brakes from Poterfield racing. They've been in racing for years and make a quality pad.

Too easy to warp stock rotors. Haven't had that problem with slotted ones.

To me I can brake harder over more laps with the slots. I tell the cooling affect. there's less brake fad. But then again I brake hard and deep.

Also, go with Cermaic brakes from Poterfield racing. They've been in racing for years and make a quality pad.

Stock rotors should not warp. None should, really... IF your wheel lugs are properly torqued! The concern with drilled rotors (especially) is cracking due to lack of resistance to extreme temperature fluctuation (without going into the actual physical materials reasons).

I've never liked the Hawk HP Plus and won't use them; way too grabby especially for autox, their HPS and motorsport racing pads I love though

I don't autocross, so the grabbiness isnt a huge deal for me, but i love their grip coming down into hard braking zones

as long as you're braking in a straight line it's no problem

yep, like turn 5 at Road America, or coming down into 10 a/b at Road Atlanta :)

added clarification; ... or not at ten/tenths adhesion

I'm coming down into those turns pretty hard, prob close to ABS in both situations

I use the carbo tech panther 8's(on the front) and bobcats on the back( so I dont have to switch those out for street use). They are more expensive than the Hawks but not nearly as grabby and have much more rapid progression. Makes trailbraking much easier.
If you run on a hard braking track such as Road Atlanta i suggest strongly that you fabercate some front brake ducts no matter what pad you use. They do get hot.
olddragger

I use the carbo tech panther 8's(on the front) and bobcats on the back( so I dont have to switch those out for street use). They are more expensive than the Hawks but not nearly as grabby and have much more rapid progression. Makes trailbraking much easier.
If you run on a hard braking track such as Road Atlanta i suggest strongly that you fabercate some front brake ducts no matter what pad you use. They do get hot.
olddragger

What would you use to make those ducts?

http://www.rx8club.com/showthread.php?t=83801&highlight=BRAKE+DUCT

RacingBrake says no need for ducts on theirs, simply removing the OE brake shield is all their BBK requires for Road Hotlanta, etc.

RacingBrake says no need for ducts on theirs, simply removing the OE brake shield is all their BBK requires for Road Hotlanta, etc.

The brake shield HAS a duct, though. Maybe it gets in the way of their kit, but there is a big flare at the front of the shield to draw air into the rotor (and then out the veins).

The rx7store.net rotors (Brembo blanks, slotted) and Hawk HP+ pads worked AWESOME at Mid-Ohio this past weekend. I even have pad left! This is a first for me. I usually go through a full set in 1 weekend.
The track was just finished being repaved the week before we got there. It was super smooth. I'd never been there before and had a blast. Videos will be posted over the weekend, hopefully!:ylsuper:

The brake shield HAS a duct, though. Maybe it gets in the way of their kit, but there is a big flare at the front of the shield to draw air into the rotor (and then out the veins).


it's a flair, not a duct, and it's contained fully within the inside of the wheel shell :rolleyes:. RacingBrake doesn't recommend ducting air to the rotor unless you design the ducting to feed both sidesof the rotor evenly, the reason is because if you feed to the backside only it creates a thermal imbalance on the rotor

SpeedSource makes a duct kit that feeds both sides of the OE front brakes, they are presently testing the RacingBrake 2-pc rotors ...

Both the standard and Enkei wheel RacingBrake BBK's require one very small corner on the brake shield to be trimmed for clearance of the caliper mount. The rotor sits much further inboard on the Enkei wheel BBK, this requires a small area of brake shield protrusion near the tierod to be knocked down slightly with a hammer. Otherwise the brake shield works fine with their BBK, they recommend taking the back shield off because for track use it actually traps more heat than it relieves.

it's a flair, not a duct, and it's contained fully within the inside of the wheel shell :rolleyes:. RacingBrake doesn't recommend ducting air to the rotor unless you design the ducting to feed both sidesof the rotor evenly, the reason is because if you feed to the backside only it creates a thermal imbalance on the rotor.

As I understand it and see it, air is ducted (or "flaired" :p: ) to the inside of the rotor at the hub and it should go through the veins from the inside-out. This would cool BOTH sides of the rotor through the veins. If you noticed, our stock rotors, as well as the ones I replaced them with, have a thicker outer disk than inner disk. I agree that there would be some disparity in cooling on the inside and outside, so it seems that it's been accounted for (to some extent) by giving the outer disk greater heat capacity by increasing it's mass. This is done front AND rear.

the difference is the OE rotors have straight vanes whle the RacingBrake BBK rotors have curved vanes and their rotors are unique in that the attaching hubs are center-mounted, they generate their own flow through the rotor through both the inside and outside, and I just happened to have a BBK disc on my table, it is the same approx. thickness on both sides

However, like I said before, RacingBrake generally does not recommend ducting or brake shields on their BBK kits for general track use ... if you need ducts for say, a multi-hour endurance race, then make sure you have air feeding to both sides of the rotor

RacingBrake says no need for ducts on theirs, simply removing the OE brake shield is all their BBK requires for Road Hotlanta, etc.


and of course, SpeedSource makes and sells a ducting kit for the OE brakes that feeds both sides of the rotor, it would be a lot easier and less costly to feed the inside only if that was sufficient ... but what do they know compared to me or you :hahano:

I couldnt find any info on the Speed Source site about the air ducts. Do you have a link?

Mainly curious if it will work with an intercooler in the way, and with the MS Bumper. I am thinking the MS Bumper shouldnt be an issue since thats what they use.

-hS

they don't advertise on the web, you have to call

Will do

Speed Source producsts are generally out of my price range at the moment... but i'll find out anway. This maybe more reasonable a year from now.

-hS

if you don't get it soon you'll only be able to get it through access to the MazdaSpeed racer program:


http://www.rx8club.com/showthread.php?t=83108

apparently I didn't quite get it right, the RacingBrake link below goes through a number of rotor design features and discusses the differences. Mention is also made about the brake shield. I wasn't aware that RacingBrake uses more curved ventilating space vanes on the hotter outer diameter of the disc than the inner. I found it interesting ...

http://www.racingbrake.com/main/rotor_vane_design.asp

also I edited a correction in an earlier post, SpeedSource is testing the RacingBrake 2-pc rotors, not BBK. They are required to keep the OE calipers per the rules. Word is that their testing went very well ... :)

So, I said earlier in this thread that I'd post videos from Mid-Ohio, and I have in another thread. Just to mention it here, they're at www.scottbarton.net/anthony/mid-ohio/videos
right-click and save-as to your desktop

I looked at my pads and I (incredibly) have 1/2 the pad left and the rotors look brand new! I've never gone through less than 85% of my pads in a weekend!

Anyway, the HP+ pads and rx7store.net slotted brembo rotors worked great.

So, I've been looking at Spin9k's ducts and like the idea. I'm surprised that Mazda didn't put in actual ducts (not to be confused with the "flairs" that I referred to before, lol) in this car. My former '95 325is had ducts in it from the factory.

Does anyone think that Mazda would have a problem if I returned my leased RX-8 with cooling ducts installed? What's the worst that could happen? I'd have to buy a set of wheel liners?

cooling ducts would be a clear giveaway that the car has likely been tracked, I wouldn't advise turning it in that way less you get dinged or even forced into making a purchase

your BMW didn't need twin oil coolers in the nose instead ...

your BMW didn't need twin oil coolers in the nose instead ...

true story.