1st Gen Rx7 Brakes

[Scott Nutter]

So, I need a new front set (a new lower set probably wouldn't be bad either but way out of my price range, not to mention the pain)

I've been running the Carbotech pads for the last couple of seasons and really like them. They stop the car and they wear out over 2 seasons ( ~12 weekends ) not wear out the rotors in 2-3 weekends like Hawk Blues. However they have gone from $95 to $145...Dang!

I was talking to a Hawk representative at the ARRC last year and he said they have a new compound that is easier on rotors. Has anyone run them, what is the compound, and what is the cost.

Thanks

[SLUF]

Subscribing for info. We are going to switch to Carbotechs after chewing thru rotors every other weekend with the Hawk Blues. Would like to hear from anyone on the new Hawks as well.

[Tak]

What do you mean 'chewing' through rotors? Running blue's I always end up with cracked rotors after 3 or 4 weekends with virtually no wear on the rotor. What are you guys seeing? Which Carbotech pads are you running?

Thanks,

Tak
#29 ITA Rx-7
SFR

[dickita15]

I have always run Blues I used to have a lot of cracked rotors even though I am a bit of a pussy on the brakes. The two things I have changed to stop cracking rotors is changing the pads at half way (as soon as the groove is about gone) and second not using the brakes on the cool down lap and not touching the brake as the car rolls to a stop. The only time I crack rotors now is if I have a spin in traffic when they are real hot and I have to lock down the brakes while traffic gets around so I cannot get moving right away.

[TomL]

I run Hawk Blues as well, and I've never seen the kind of wear you're describing. I get about the same use out of the pads as I do on the rotors - at least 6 and sometimes 8-10 weekends, and those are mostly doubles. I don't do anything special to keep down wear and I've gone to using the absolute cheapest Chinese-made rotors ($38 apiece) I have found. I've found no discernible difference in lifetime between them and Brembos or other "quality" rotors. The only "problem" is that the dust cap is a little loose fitting (fixed with RTV.) The cheap rotors act just like the good ones - after 3 or 4 weekends they start showing heat checks, which gradually get bigger. When the cracks get close to the outside edge, I change them. Occasionally, they'll even get a single crack that goes all the way to the outside edge, but it's never caused any noticeable degradation in performance.

Maybe your experience is related to the tracks you run? But if so, I'd think you'd be wearing out the pads quicker, too.

[SLUF]

We are running at St. Louis, Memphis, and Hallett. We are getting approximately 150 laps or two to three weekends before the rotors are completely cracked to the point of being unsafe. We are running cooling ducts and I don't think we are that hard on the brakes as we are just not that fast yet. I have seen and heard some racers getting better life out of the Hawk blues but not too many for sure. We will be switching to Carbotech after this set.

[mustanghammer]

I guess I don't understand the issues being described because I haven't cracked a rotor in 7 years of using Hawk Blue's front and rear. I have also never experienced any brake fade. My car currently weighs 2470 - the lightest it has ever been - with my fat ass in it. Please don't take this the wrong way....but maybe you are using the brakes too much?

As far as tracks go, I haven't been to Memphis or Hallet (I really need to get to Hallet) but I have raced at StL, MAM and HPT. None of those tracks require allot of heavy braking in my opinion. The RunOffs configuration at HPT is extremely kind to brakes. StL isn't too bad either. Both allow an RX7 to carry allot of momentum and ask the driver to give up speed in stages - not all at once.

Here is my routine:

Front rotors are replaced after they have seen their second set of pads.
Brake pads are replaced when the friction material is thinner than the backing plate and not before.
I do not turn rotors.
I buy cheap rotors from Black Dragon or a national autoparts chain
I inspect and repack bearings at pad half life and when new pads are installed on old rotors.
New rotors always get new Timkin or National bearings an races
I use high quality grease from Amsoil or Lucas - I am worried about a wheel bearing failure because they are so small.
Let us know how you like the Carbotechs.

[Ron Earp]

Guys that are cracking the rotors and having short pad life, do you have caliper and rotor ducts on the brake system?

[SLUF]

I guess I don't understand the issues being described because I haven't cracked a rotor in 7 years of using Hawk Blue's front and rear. I have also never experienced any brake fade. My car currently weighs 2470 - the lightest it has ever been - with my fat ass in it. Please don't take this the wrong way....but maybe you are using the brakes too much?



Easily could be the answer! We are chasing some braking issues with the car and this may also be a contributing factor. Trey and I are using the car at HPDE/PDX events and we have even cracked rotors in two weekends of that lighter use. I wish I had a better handle on this for us but I don't. All my research has indicated that Carbotechs are much more rotor friendly than Hawks. My weight is identical to yours it looks like. (Except my son who manages to be 75# lighter for some reason! I hate kids!) If you get a chance to go to Hallett in a few weeks I'd love to chat a bit about this.

[TomL]

I run 3" ducts that are directed at the calipers. Have trouble finding room for disc ducts, too. To be honest, I don't think what I have is excessive wear - 6-10 mostly double weekends before cracking - considering the size of the RX7 discs. And it's comparable to other vented disc cars I've run. Solid discs seem to last longer, so maybe that's why you may be seeing longer life on yours, Ron.

[lateapex911]

Don't forget to work with the chassis settings to get as much work done by the rear brakes as possible.

Also, I'd duct to the rotors before I'd duct to the calipers, if I had the choice...

Finally, how the ducts are presented to the air is important, of course. I've seen lots of cars with just the tubes hanging under a bumper cover, flopping around in the breeze. Even at rest it looks sketchy, but at speed, yea, not very effective.

[mustanghammer]

Easily could be the answer! We are chasing some braking issues with the car and this may also be a contributing factor. Trey and I are using the car at HPDE/PDX events and we have even cracked rotors in two weekends of that lighter use. I wish I had a better handle on this for us but I don't. All my research has indicated that Carbotechs are much more rotor friendly than Hawks. My weight is identical to yours it looks like. (Except my son who manages to be 75# lighter for some reason! I hate kids!) If you get a chance to go to Hallett in a few weeks I'd love to chat a bit about this.

I can't make the Hallet race. I am looking at running the MAM race later that month. There should be several people you can talk to about this at Hallet, however. Look up David Long - EP #82. He was the second owner of my car (I am the 4th) and he put allot of the good stuff in it. So he knows what it has and what my maintenance routines are because I keep my car at his shop. Also Charlie Clark (EP #6) is another great source of 1st gen info. If you do what Charlie says....you will go faster.

My brake ducts are attached to modified backing plates - made by ISC I believe (they were on the car when I bought it) The other end of the duct attaches to the air dam and has and an unobstructed access to air. I am not ducting air to my calipers put some E Production cars do.

I do use high quality fluid - Motul, Willwood, etc and bleed my brakes before every event and as needed between race days. I rebuild or replace the calipers every couple of years and I have braided flex hoses front and rear.

Good points made by Jake regarding suspension setup. If your car transfers allot of weight to the front during braking you are not getting the full use of your rear brakes. My car was setup based on the GForce engineering tech manual www.gforceengineering.net (http://www.gforceengineering.net)

[miketrier]

I ran a 1st gen RX7 with Hawk Blues for several years without brake problems. Like Scott, I had ISC modified backing plates on the front and collected air from a duct in the air dam. I changed pads and rotors yearly, ran approximately 5 race weekends of 2 qualifying sessions and 2 races each weekend. I too used full synthetic grease (Valvoline black) and repacked frequently. My only brake problems were when I tried to change from Hawk Blue to Black on the rears and they would lock up. Changing back to Blues fixed the problem. I can't give any help on new Hawks or much else about brakes. I probably was relatively easy on brakes but they guy who bought my car runs it harder and doesn't have problems either.

[Tak]

I race at Laguna Seca, Thunder Hill, and Sears Point (infinion for the blasphemous). Laguna is brutal on brakes, T-hill is hard on brakes, and Sears is moderate.
Yes, getting the rear brakes working drastically incrases front rotor life. I find rebuilding the rear calipers every other year really helps maximize braking at the rear. So does soft compression damping, not possible with tokikos.
3" ducts from spoiler to Mazda comp (ISC??) brake ducts/backing plates. Not using the brakes on the cool down lap helps a lot, as does rolling the car 12" every 5 minutes after coming off the track (otherwise the rotor under the caliper stays hot as the rest cools). Laguna is just plain hard on brakes, and I will occaisionally overheat hawk blues there (hard pedal, less deceleration than normal).
I'm giving away my speed secrets here. I do NOT run the chinese rotors--I've found they are typically 2 to 3 lbs heaver than Brembos.
Tak
ITA 29, SFR

[kgobey]

This is an old discussion, but I'll join in... Remember with Hawk Blues, if you cannot get the rotor to temp it will destroy the rotor