Hello,

I've had more days on track this season than I have in the past, and I wanted to relay the problem I spent much of the season trying to solve.

I started out the season with EBC YellowStuff pads. I loved them for autocross, and they did well for the very short sessions I was doing in HSAX. In those events I was doing, at most, four laps at a time.

This season most of my events were HPDE-format, with 20min or longer sessions. In the very first one the EBC pads showed they were not up to the task. They kept working, but when I removed them after the day they looked like they had re-entered the atmosphere from orbit. Also, the car shook like it had warped rotors.

For the next event I put on new aftermarket rotors and Hawk Street/Race pads. I have never had a problem buying the cheapest rotors I could get, so that's what I did.

As soon as the brakes were hot, the vibration came back, as if I had changed nothing. I did a couple more days on track with this setup, trying different techniques for warming the brakes up, but they always vibrated once hot.

For my last day on the track I replaced the front rotors with OEM parts from Mazdaspeed. I went so far as to put in the little screws that retain the rotors. I also replaced the front pads, because the brakes had gotten quite badly grooved by then. I wanted a fresh start. The Hawk pads, with three pretty hard days on them, had more than half their thickness left. One was pitted, which suggests to me that it got too hot. That seems unlikely, if Hawk's claim that the pads work up to 1200degF is accurate.

Anyway, the new pads and nicer OEM rotors worked very well on my last day on the track. Once they had warmed up and broken in a little, I didn't have to think about them for the rest of the day.

So there you have it. Maybe don't put cheap rotors on the track.

One final note: I have tried to use temperature-indicating paint to get some data on brake temperatures. I wanted to know how hot they were actually getting. Sadly, after three attempts I still have no information. The paint always flakes off during the first session I use it. If anybody has used this stuff and has any advice, I'd be glad to hear it.

 

I've been using Centric 125 high carbon rotors on track with good success so far. They're not much more expensive than the normal 120 series and claimed better lifespan, so I figured why not.

 

Pockets, I'm not sure what Hawk pads you are talking about. HPS is not really up to serious track time, at least not on the fronts. HP+ or better is required.

Some basic checks: Are you torquing your lugs before every track day? I do mine the morning of every track event. Are you cooling everything down after the session? The "cool down" lap post-checker is just that. I don't touch my brake pedal from the checker to pit-in. And of-course I don't set the parking brake.

For rotors I just use Centrics. It's been a couple of years and three sets of Hawk HP+ pads since I changed them - I've lost count of how many track days are on them. They will be replaced this Winter just because, and because they are finally showing heat checks (tiny little cracks) in the outer portion of the swept area. I don't have any fancy ducting or special cooling.

 

Also when your car is sitting in the paddock area after a hard run don't let it just sit in one place without rolling it forward and back a few times to move the pads to a different location on the rotor to prevent heat sink warping of the rotor.

 

I appreciate all the replies. I'll try to answer all the comments at once:

1. These are the pads I am using for now: High Performance Street Race | Hawk Performance

Without any real temperature data to go on, I chose between these and the HT-10, which were the two recommended by the vendor I spoke to. If the S/R pads prove to not have enough range, then I'll try the HT-10. The vendor told me the HT-10 would be harder on rotors, so I thought I'd try the gentler pad first.

I am told the S/R pads are essentially a DTC-30 with chamfered edges and backing plates. These changes were made to make a more 'streetable' pad. It's a relatively low-torque race pad, which I like because I'm using street tires and I have a tendency to overwhelm them.

I have used the HP+ when I did Solo. I did not like it very much. When it got warm the initial bite was far too much for my taste. I found them difficult to modulate, but that was years ago.

2. It looks like the rotors that I replaced after only a few days on track were Centric, P/N 121.45071 and 121.45072. Without track speeds and temperatures, they felt fine. It was only after a lap or two of a track that they started to vibrate under braking.

3. I hand-torque torque my lug nuts before every event because I trailer a dedicated set of wheels to the track with me. I set the torque wrench to 90lb/ft.

4. I used to use the cool-down as more practice. I don't any more, and I am usually gentle on the car for this period. I also leave the car running with the hood open after sessions or laps to let it cool itself off. No, I do not set the parking brake. Yes, I roll the car back and forth so the pads don't sit on one spot on the rotors.

Again, thanks for the replies. Always nice to talk to a community about stuff.

 

I used a set of generic blanks and now centric high carbon. No issues with either and I get my brakes hot. What paint are you usinf? I hit over 1400F at the front according to the thermal paint I tried (don't know how much over though), and around 1400F at the rear (paint changed, but it took a few sessions). It would not surprise me if I am up at 1600 or 1700F at the front. This can be very driver and track dependant though. I am somewhat notorious for killing brakes...

Vibration is most likely from uneven pad deposits. Can be from the way they were broken in, not fully cleaning new rotors, or overheating pads on track.

I always re tighten lug nuts after the first session, or having driven some miles. They can loosen a bit after the initial torquing up.

Never had an issue breaking in or uneven deposits with either dtc60 or st43. I swap the OEM pads back in for the street. I have had some very minor vibration after swapping back, but it tends to go away after a bit, or after a subsequent track session.

 

Those street/race pads are compromise pads, and the saying goes that compromise gives you the worst of both worlds. They may not be the best choice. I don't have any personal experience with them.

HP+ pads are a bad choice for autocross. No surprise you didn't like them. On the track, however, they are wonderful. Long life, good torque, no fade, long rotor life, no "deposits", and cheap. They are completely unconcerned with bedding-in and rotor condition. I never have to bed them in or clean the rotors be they new or old. Just slap them on and go.

Just like they are no good for autocross, they aren't really any good for the street. Since I drive my 8 on the street I change to track pads just before a track event, and put street pads back on afterwards. Takes 20 minutes to do the fronts without power tools, 45 minutes to do all four corners (with the right tool for the rears).

I do recall that years ago I had one set of Centrics that appeared to be warped. I measured the run-out and it was within spec, but I still had vibration. Swapped for new rotors (also Centric) and the problem went away. I had those rotors turned and tried them again, still vibrated so it wasn't "deposits". I don't know what the problem was, but they went into the trash. That's what nice about cheap rotors; just trash them if there is a problem! I think I'm only on my second set of rotors since then and the problem has not returned.

 

I have always used Centrics as well and I have never had any issues. I use Hawk HP+ on them which I know a lot of people don't like, but I like a sensitive brake pedal. A long time ago I also was in a jam and had to use Napa's Adaptive 1 pads at Streets of Willow on the Centrics and no issues at all even hot lapping them. I was blown away, haha

While Centrics are cheap, they are made by Stoptech so maybe they have higher quality control than other "cheap" options out there...?

 

a buddy of mine was told the same between the DTC-30 and the Street/Race compound, which is relatively new marketing-wise from Hawk.

If it really is the same compound as the DTC-30, it may be more of a track pad than a street pad, I would think... the DTC-30s are pretty hard to find for the 8, IIRC. I have a set of DTC-60s waiting to go on after the HP+ die...

 

Yeah, the Street/Race has characteristics that are much more like a track pad than one made for the street. It's catastrophically dusty and makes an incredible amount of noise. I rarely drive my RX-8 to work, but when I do I can actually see the dust that's accumulated in the mere three miles I've driven.

Still, they may turn out to be insufficient. Time will tell. I doubt they were the reason for the 'warped' feeling in the brakes, though.

 

The paint I bought is made by Tempilaq. As an art supply, it leaves much to be desired. It's clumpy and difficult to work with. It comes in three bottles, each to indicate a different temperature threshold - 750, 1000 and 1250degF. I suspected that the 1250 had been melted in one instance, and if you've measured 1400degF, that's possible.

 

I've found cheap rotors to be very hit and miss. Sometimes they work, sometimes they warp because they have internal stresses associated with cheaply produced metal. I always try to go OEM, although right now I have R1 slotted rotors on, they seem to work well with my street pads, but the slots make some vibration with my track pads (Porterfield R4). Probably because there's no chamfer on those pads.

 

I used the same paint, only went for 750, 1000 and 1400 degF bottles. Out of the 3 bottles I received two were smooth liquid, one was a bottle of dried up clumps that would not stick to anything. Seems like the lid was not secured properly. I returned it and received a replacement without that issue.

I'd agree that it is difficult to tell if the paint has changed or not though.

I should pull them out and take some new measurements. It's been a couple of years since I did and a lot has changed.

Looking at the data on the hawk website, it does seem that their Street Race compound is the same as DTC-30:
Compound Graph | Hawk Performance
Race Compound Application | Hawk Performance
Street Performance Compound Application | Hawk Performance

 

As long as I break in the pads correctly and use OEM rotors I've never had a problem. I usually use Carbotech pads but have also used Hawk and Raybestos Racing.

 

I reviewed Hawk Street/Race pads in this thread:

https://www.rx8club.com/series-i-whe...5/#post4663212

The upshot is I felt they had too much initial bite and overall torque for street tires. They were dusty, and wore out very quickly. Temperature tolerance was good. Except for the noise, I probably prefer HP+ on the track.

But... I next tried Carbotech XP10 up front and XP8 in the rear and fell in love. I will never look at Hawk pads again.

As for rotors, I have used OEM and Centric and have never had any problems as described by the OP. I hand torque my lug nuts before and after the 1st session of the day, which may or may not make any difference. As for cooling the brakes, I have found that jumping off the track onto the highway for a cruise of 3 miles away and 3 miles back at 70mph cools everything down nicely. I have not not had any trouble with cooked pads or boiled fluid since I started doing that.

 

^Carbotech XP10 is more equivalent to Hawk DTC-60 in temp range & price, so the comparison with HP+ or Street/Race is a little unfair. That set, your comments on bite would lead me to think you will still prefer XP10 over DTC-60.

 

I do not find that to be true in terms of temperature range. I have experienced very little fade with Hawk's Street/Race pads (and even HP+ on the smaller/tighter tracks). I do experience noticeable fade late in every session with Carbotech XP10s, but that does not turn out to be a problem for me, as I am typically driving on greasy tires at that point anyway. I might agree if we were talking about XP12s, however.

IMHO, YMMV.

.

 

Huh, interesting, I was assuming they solved the fade you had with the hawk pads and that is why you preferred them. I have used xp10 on my civic, but not the rx8. To be honest, I was not a fan of them on the civic, as I never got a firm feel from them and they wore out extremely quickly. DTC 60 seemed to work better for me, although they are not perfect either. I was still thinking xp10 would hold up better than the lower temp hawk pads, but never tried those myself to compare.

 

The only time I experienced any fade with the Hawk Street/Race/DTC-30 pads was on the first day of use. Once they were fully bedded and finished outgasing, I never really noticed it again. The XP10s do eventually fade, but they are so much better in terms of initial bite and modulation, that I am more than willing to accept that trade-off. I find them to be much more linear than the Hawk pads I have tried, which means I have to apply more pressure to max out their stopping power, but I like that--especially when using heel-toe to downshift.

Of course, the performance of any pad varies from track to track, from tire to tire, and from driver to driver, so it is all relative.

.

 

Pads haven't "outgassed" since the 1960's. It's just the bedding-in.

Pad performance doesn't vary. Driver performance definitely varies.

I am almost convinced to try XP10/XP8. I love the HP+ pads, but think I it worth expanding my experience. If I don't like them I can sell them to Mr. Dallas.

Steve Dallas, any of your track videos posted?

 

Just repeating what the Carbotech guy told me on the phone.

I'll PM you my YT channel when I get home tonight.

If you buy Carbotech from Mazdaspeed Motorsports, they come pre-outgased for the same price as non.

 

Having been on 8s, 10s, and 12s...

If you have any sort of talent on track, I'd recommend starting with XP12 front, and 10 or 12 rear.

10s and 12s has the same pedal feel, so that won't change. The lower end temp threshhold of 12s is 275F, only 25F over the 250F of 10s, but it has a 400F upper threshhold increase.

I was hitting fade on XP10s in my MSM on track, 500lbs lighter but with marginally higher terminal speeds. I switched to 12s and haven't hit fade since, despite continuing to get much faster.

What I'm getting at is since 12's lower threshhold is still low enough to street drive them safely, they aren't going to be "too much pad" for where you are at, but have plenty of room to grow. XP12/12 in the 8 the stopping power is ... well, full ABS stop was described by my GF as "violent". You DO need to make sure they are bedded in properly, but once bedded in my oh my do they work. Consistent, solid, firm, linear, and very very high torque at max pressure.

 

dang, I feel like RIWWP just called me a noob, lol!

 

After instructing on the Shenandoah this past weekend, I can say for-sure that DTC-60's are way (WAY!) too much pad for a Miata on 200 treadwear street tires. Good grief...

There were FOUR RX-8's there including hufflepuff and Gdawg522, which was pretty awesome. Would have been five if I'd gotten my **** together and fixed mine. But .

On-topic, hufflepuff gave me a ride in his white base model. He's running Hawk Blues and they worked just fine. He didn't really have any complaints. Mind you, he is also an instructor and currently races an Integra too, so he falls under the high end of the "Driver performance definitely varies" that I mentioned before.

 

^I've been fine with DTC-60 and 255/40/17 Direzza Z2 (200TW) tires on the RX-8 in good conditions. I can imagine on a lighter car, with less grip, and no abs things might be quite different though.

Just to emphasize a point, pads are really driver AND track dependent. I struggle to get my brakes hot enough for DTC-60 to work consistently at Sonoma, but at Laguna Seca I am at the upper end of the temp limit and have to be careful once they go below 50% pad material as they disintegrate faster and faster at that point.

From some of the other comments in this thread, it seems like HP+ are punching above their class in thermal capacity. I'm tempted to give them a try at some point.

Also tempted to try XP12. I am pretty sure XP10 won't work for me at Laguna or Thunderhill.

I have always run the same compound front and rear on the RX-8, so I'd do the same with carbotech (rather than some xp12/10 or 10/8 combination).

Hoping to try a relatively unknown pad (CL5+) at Sonoma next month, so will see how that goes... They are pricey, but had the best feel and widest working temp range of any pad I tried on my civic.