SouthFL

Advertised operating temp ranges for commonly used track(able) pads for the RX8.....

Cobalt Friction
XR-3________ 50-1600 deg. (Front)
XR-4________ 50-1500 deg. (Rear)
GT Sport_____ 50-1200 deg. (Front/Rear)

Hawk
HT-14_______ 300-1400 deg.
HT-10_______ 300-1300 deg.
Blue________ 250-1000 deg.
HP Plus______ 100-800 deg.

Porterfield
R4_________ 450+ deg.
R4S________ Ambient-900 deg.

Carbotech
XP12_______ 250-2000 deg.
XP10_______ 200-1650 deg.
XP8________ 200-1350 deg.
AX6 (Formerly Panther Plus)
___________ 150-1250 deg.


Please feel free to add any others.


__________________________________________________ ______________

Looking at these all listed helped me paint a better picture as to the spectrum of compounds which we have as options. It's definately helping me make my post HP Plus choice clearer.

Gecko69

Racing Brake :

ET300 not rated
ET500 up to 1000 deg.
ET700 up to 1200 deg.
ET800 up to 1400 deg.
ET800 up to 1600 deg. - 300 deg. minimum temp.

mwood

Either Cobalt Friction has some very unique and innovative compounds, or their numbers are advertising hype...50 degree cold bite on a 1600 degree pad?

costello

Yeah, I don't get that either. I used Cobalt Friction 3 or 4 years ago on a Honda Prelude (also 3000 lbs. car). Not sure if their compound has changed much, but back then they had NO cold bite. Once warmed up they were fantastic though. Felt they had more stopping power than the Carbotech XP10, but the Carbotechs have pretty good cold bite even when rated at 200. I can drive to the track on the XP10s without any problems.

Asmoran

friction coeffecient graphs look like a dyno chart, but with temp instead of RPMs. So think of it as mazda saying that the renesis produces power from 500 to 10,000 RPM. While it's technicallyt true, it doesn't tell you how much or where.

mwood

Sure, if you apply any clamping force to the rotor, with any medium, you will generate some measureable coefficient of friction...but, that isn't the description commonly used in describing "operating range", which implies the pad compound is actively transferring material to the rotor...which I can't see happening at 50 degrees on a 1600 degree pad

SouthFL

I'm going to call Cobalt Friction tomorrow to inquire more about this. I've been wondering myself.


I want to keep pad swaps to a minimum, so the Cobalt Friction GT Sport looks like my #1 option.
#2 would be running Porterfield R4S all around for daily driving and swapping in R4 pads up front for track days.

SouthFL

Spoke with Cobalt Friction today.
They recommend an XR2/XR5 (not listed) combo F/R for advanced HPDE run groups on our cars.
They claim their pad is interchangeable with any other pad as long as there's a proper bed-in. They also mentioned that it's perfectly fine for one to drive to/from the track with the XR series of pads due to their decent cold bite characteristics.
Also mentioned during the conversation- their pads are easy on rotors, however, they highly recommend not using them (even the GT Sport) as daily driven brake pads.

On another note,
I had spoken with Hawk yesterday and they outright say that their Blue pad is harsh on rotors, recommending the HT line of compound instead.

And yet another note,
Spoke with Porterfield and they maintain that the R4S as a rear pad will do just fine with the R4 up front.

mwood

Good information which makes sense, to me, anyhow!

SouthFL

Well, I'm determined to do as little pad swapping as possible for track days (it just makes these events much more enjoyable), so I'm going to give the Porterfield R4S a try. I'd like to see how they compare to the HP Plus. If they're overwhelmed, I'll throw in the R4 up front.

The HP Plus really dust way too much for daily use, plus the amounts of dust at track days is pretty high - I'm going to have to take a speedball to my stock wheels to get the black out- they've got some serious dust deposits that won't come off from regular washing, so hopefully the R4S will help in that department, as I'd like to preserve my new daily driver wheels.

Track day before/after pad swaps both front and rear may be inevitable. we'll see.

TeamRX8

iTrader: (25)

sorry, those numbers don't really mean sh-t, particularly on the low end

you also forgot to list the Hawk DTC compounds, those are all the "old" compounds

SouthFL

Hawk tech. didn't recommend DTC. Said to stick with HT series.
DTC seems to be for high horsepower, heavier cars (GT class cars and up).
The operating range on the DTC line begins at 500 degrees.

A guy next to me in the paddock one day tried using a DTC pad and I saw his new rotors crack in several places. The temperatures were really, really high. His brakes were smoking for about 10 minutes after each run.

SouthFL

Also, this comment really annoys me. Please explain why you believe they "don't mean sh-t."

If the car's braking is effectively done within a certain temperature range, then why get too high of an operating range of a pad? Conversely, a pad with too low of an operating range for the application and the pad loses its characteristics (fade). Thus, analysis of the pad's range does bring merit.

Comments like the bolded above makes members take your own perspective on things with a grain of salt, ultimately, not contributing to the forum's agenda of technical discussion, and ultimately, leaning more towards straightforward insult typically reserverd for the lounge. In my opinion, this tarnishes the credibility which you wish to assert yourself with.

Razz1

I can vouch for the R4S on the rear. Drove 2 yrs 10k miles and 5 track sessions with an addtional two Auto X.

I still had 30% or more pad left when I replaced them this year.

SouthFL

Did you use R4 up front? If so, how was the bias in feel?

SolarYellow510

Hawk catalog used to claim ~1600F for the HT-10 and HT-14. They've been downgraded in the catalog now that DTC-70 and -60 are their top materials.

Three respected brands haven't been mentioned.

PFC 01 and 97 are awesome sprint race compounds. RX-8s without FI probably don't have any use for them.

Some Pagid pads are pretty much unbeatable for endurance racing, as long as temps are kept within limits. I'm interested to find out if the effective temperature management of the generously-braked, underpowered RX-8 makes the economics work out well for them. Pagid Orange is a good dual-purpose material, but can squeal pretty bad when cold.

Ferodo DS2500 is a nice, if dusty, dual-purpose pad.

I haven't bothered to see which of these pads are available for RX-8.

Also, the Axxis ULT is a really great value, and I may try it on the track with street tires (but not r-comps). I have a friend who uses it in his '99 Miata with RA1s. The failure mode when maximum operating temperature is exceeded is uneven material transfer and judder. If you stay under that limit, it's pretty nice.

Is anyone wired up with a sliding shoe thermocouple to log rotor temps around the track?

Razz1

I think I did for the first 6 months but since then I have used R4s front and rear.

The good news is I bought an extra set and it was in the garage for a year.

Spin9k

Old posts I realize, but I'll add my ongoing user experience. I have used the Cobalt Friction GT Sport for over 1 1/2 yrs now. Car is daily drive, but mostly leisure and track use, no commuting, I have another car for drudge work. The advertising about 50 degree-1200 use range is not just hype in my experience.

I've driven in sub-zero winter, spring, fall, summer and on track - I haven't been able to notice any difference in grip cold to hot - none. They work and it's not that I have to stand on the brakes when cold...there really is the same immediate friction and braking every time, as far as I can determine.

I never removed the pads until yesterday- and I found the wear on the rotors was minimal and they are still flat and true - no groves or ridges. I have an '04 ('03 delivery) with original rear rotors and RB slotted 2p fronts 2.5 yrs old. I'm unsure why CF says don't use these pads as a DD, they seem to work fine as far as I have experienced. Tha perfect combo track/street pad IMHO.

Yes there is significant dusting, but it does seem to wash off no problem, I do keep the car clean and wash the wheels often and regularly so I don't let anything build up on my Enkei RPF1s.

Yes there is a bit of noise, but only when you are coming to a complete stop. Annoying perhaps, but what ta hey - they're performance pads after all. No biggie.

But yesterday I did take the pads off, which was a good chance to inspect them closely. There was 1/2 material left in the front; 2/3 left in the rear. That's perhaps 12K miles of use.

After a good brake cleaning I replaced those good guys with the above mentioned true track pads XR2/XR5 combo. Three days of track this upcoming weekend. I hope I'll be as impressed with these as the GT Sport!

TeamRX8

iTrader: (25)

those numbers don't mean sh-t because they're just general heat ranges, you need a mu vs temp graph to fully understand what's what. Many high heat pads will grip decent at low temp, but are very hard on the rotor surface until a certain temp is reached. Heat ranges don't tell you much because it really boils down to what the actual friction coefficient is. These are much more useful than some general temperature range quote:





a couple others to consider for street/track duty

EBC Yellow
Porterfield R4-1

Raybestos makes some decent track-only pads too.


.

Spin9k

I'm not sure to whom you're venting Team or in regards to which of the posts above numbers you're dissing...you said approx the same comment in Feb above...maybe refering to that...duno.

On the other hand, as mine is the 1st post in 5 months and if you are refering to my comments, I'm afraid I don't get your need to defend some technical points about EBC pads or mu or whatever you're in a heat about.

Rather I'm giving my real-world experience. Charts and graphs are really great for cold winter at home debating jousts, so thanks for sharing that. But real world testing and observation gets someone looking for pads to the meat of the matter, I'd wager. That's why I'm relating what actually happens on our car with these pads...for for the benefit of anyone interested.

TeamRX8

iTrader: (25)

no heat, I just never came back to the thread and only just saw SouthFL's post asking me to clarify my position, not sure why you guys always have to be wearing your oversensitive granny panties

and if charts are great for cold winter bdebating contests then general temperature ranges, which this thread started on, are only good for wiping your butt after a bout of bad mexican food

Spin9k

..oh...bad restaurant experience...now I understand... verbal overflow

SouthFL

Very nice technical post Team. Good information there.

Spin, thanks for the GT Sport feedback.

altiain

iTrader: (3)

One thing to keep in mind - although the graph goes out to 1300f, Porterfield recommends using the R4-1 primarily when the pad temperatures are under 600f and peak temps do not exceed 1000f.

altiain

iTrader: (3)

The Axxis Ultimate is a decent street and autocross pad, and may work for less aggressive drivers on street tires. That said, I generally run RA1s in an instructor group, and I found that these pads faded noticeably after five or six laps. They also (as you mentioned) left some nasty and uneven deposits on my rotors.

I wouldn't recommend these to anyone for aggressive track day use.