Grand Am Brakes for the Boss

[PeteInCT]

So far I'm very happy with the Coleman's. The downside to them is that they are all custom cut so they are never in stock for a next day shipment. The upside is they are always available and can be delivered in about a week (if not being sent out for Cryo freezing to Diversified). Paul Weston maybe able to speed up the process if I'm in a bind, but I usually have a spare set (like the stock ones I still have) and don't don't forsee a need a super fast turnaround.

 

[Boss_302]

with apologies to C33PO and R2D2………"these aren't the brakes you're looking for".........

And here's the rest of the story.

Called Brembo and spoke to an engineer and related; back in 2005 when the FR500C was homologated for Grand Am the Mustang had a two piston caliper slider caliper which was inadequate for racing, so Grand Am allowed Ford/Multimatic to use an F40/50 type caliper and of course the two piece rotors, so at the time these were great brakes.

Fast forward to now while the two piece floating rotor is a big step up from the one piece blank we have on our Boss 302's the caliper isn't.

The main drawback is the pad size the FR500C/S calipers use a FMSI D810 and D968 pad which is 10mm shorter than the D1001 pad we have on the Boss. The 810/968 will generate more heat, less surface area pads will wear faster.





Also spoke to some folks in the brake industry about why Miller Motorsports Park uses this setup; and he related it's more than likely to consolidate all of the brake parts they carry Boss 302 / LS / FR500S.

So what is the Brembo engineer recommending?



He related our caliper is a good caliper; the Brembo Gran Turismo isn’t worth pursuing as both are cast. But the Brenbo GT is radial mounted and has a two piece floating rotor (the rotor is the main reason this is higher on the scale).

Next is the GT-R, a good caliper machined from billet, has vented stainless steel pistons, no dust shields but does have a double inner piston seal, is radial mounted and has two piece floating rotors.

Then there’s the race range machined from forged metal, has vented titanium vented pistons, no dust shields single inner piston seal, is radial mounted and has two piece floating rotors. And is completely rebuild able. Call Rehagen Racing and buy this Brembo 14 Pro Series Racing Kit http://rehagenracingproducts.com/product.sc?productId=1698&categoryId=12

Each system of course is a step up, the radial mounting on all means the caliper is mounted more rigidly but unless you are going to go to the GT-R or race stuff, just go with a good quality two piece floating rotor and a good race pad.

He also added two piece rotors are the same that comes down to the rotor ring material and the number of vanes in the hat along with the air gap and rotor thickness…………

So I’m staying with my stock calipers for right now and going with the Girodisc two piece floating rotors. I’ll also be replacing my seals soon because I cooked the dust boots……………..

 

[Shaun@AED]

Girodisc does NOT use coleman rotors. According to Mike at Girodisc below his is explination of the differences:

The FTBR rotor uses a Coleman rotor casting, the metallurgy on those rotors is just fine however the rotor itself is only a 32 vane vs. the Girodisc’s 48, the Girodisc rotors are also precision balanced unlike the Coleman rotors which don’t get balanced at all. Additionally Coleman is terrible at machining flat rotors, the DTV and runout on their rotors is never anywhere close to our tolerances, the rotor itself must be remachined and inspected on a fixture to measure DTV and runout to be sure it is within spec. This is a process that all Girodisc rotors go through before they leave as evident by the inspection sticker on the rotor showing the amount of runout on that given rotor which is usually less than 1 thousandth of an inch.

Additionally the FTBR rotor appears to be a bolted rotor unlike ours which is a full floating design to accommodate the differences in thermal expansion between iron and aluminum. Also we use spring clips to keep the rotor from making the notorious clicking noise you get with many floating rotors.

The FTBR rotor machines their slots out over the edge of the rotor, most claim that this is to expel unwanted gassing from the pads but the realization is that pads don’t gas anymore and they haven’t since the early 90s. The slots going over the edge like that just create a stress riser which will lead to premature crack propagation over the edge of the rotor, the worst place.

Last but not least you can talk about the thousands of race cars and exotic cars that have been beating on our rotors for the past 10 years, our reputation usually speaks for itself.

Here are pics of my Girodisc rotors with SS lines and Magic pads, which dust a HELL of a lot LESS than stock and stop a LOT better (limited street / strip driving so far).

 

[VoodooBoss]

Girodisc does NOT use coleman rotors. According to Mike at Girodisc below his is explanation of the differences:

Thanks for clarifying that.

 

[cloud9]

My DBAs have some uneven pad desposits from overheating my pads at Road America (go figure) so I pulled them off and am going to drop them at the brake shop tomorrow and have them lightly turned so I can start over with a clean face to rebed them. I installed the Frozen Rotors I got from Diversified Cryogenics which he said are a Raybestos blank. They were only $300 a pair and weigh 3.4 lbs more than my DBAs. I think I'll give them a go at BIR in two weeks to see how they do. I'll have my DBAs as backups....or I'll swap them back....not sure but tired of swapping rotors lol. The way my set of stock blanks have held up as backups has me thinking maybe the cheaper ones are the way to go anyway ??? I like the looks of the Girodiscs and will probably give them a shot next and ship them for cryo treatment.

DBAs (shuddering under hard braking due to pad desposits)


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Frozen Rotors after initial bed-in:



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[ArizonaBOSS]

Do Want Girodiscs in 2013

 

[LateApex]

My DBAs have some uneven pad desposits from overheating my pads at Road America (go figure) so I pulled them off and am going to drop them at the brake shop tomorrow and have them lightly turned so I can start over with a clean face to rebed them. I installed the Frozen Rotors I got from Diversified Cryogenics which he said are a Raybestos blank. They were only $300 a pair and weigh 3.4 lbs more than my DBAs. I think I'll give them a go at BIR in two weeks to see how they do. I'll have my DBAs as backups....or I'll swap them back....not sure but tired of swapping rotors lol. The way my set of stock blanks have held up as backups has me thinking maybe the cheaper ones are the way to go anyway ??? I like the looks of the Girodiscs and will probably give them a shot next and ship them for cryo treatment.

Interestingly enough, we had a Hawk brake engineer give a class at our NASA event this weekend, and he talked about rotors quite a bit. A couple of things he said that are relevant to this discussion:

- In terms of endurance, reliability, and heat, you want the biggest, heaviest rotors you can run. Mass is key here. However, you have to watch for after-session heat soak.
- Lightweight rotors can perform well for shorter runs, but especially on heavier cars, will always crack sooner. Just not enough mass to "smooth out" the heat spikes. Viable, but needs frequent replacing, and more prone to on-track incidents.
- Two-piece rotors can offer better heat dissipation. They can, however, have some rather interesting torque stress failures between the two pieces. Expensive for what you get, and more prone to failure.
- It was also stated that cryo was of decreasing value at temps over 800 degrees. Might help overall wear a bit.
- I am sure you all know this, but never use drilled rotors, and if you are using slotted rotors,only use slotted rotors where the slots do not reach the edges of the rotors, or they are prone to cracking along the slot.

Now, when I talked about my Boss specifically, he told me honestly that the OEM rotors were really nicely designed, and that unless I was racing for money with a brake and rotor sponsorship, to stick with OEM or a high-quality OEM replacement. He said the performance difference was minor at best, and that only a race team trying to squeeze every last ounce of performance out of a car within a rule set would ever really be able to justify the added expense and decreased reliability and longetivity.

I mention this here because everything he said seemed to track bang-on with what we all have experienced and observed. Was an interesting class, to say the least.

 

[cloud9]

Wow post of the month! That is great info. As you said it tracks very close to the experiences I have had with rotors. I just didn't capture it as clearly as you did. It leads me more in the direction of running the OEM style frozen rotors with slots for $300/pair. We will see how they do at BIR before drawing a final conclusion. This info also tracks with what Bill at Frozen Rotors told me.

 

[VoodooBoss]

Great info there, thanks for sharing.

 

[908ssp]

I like mine. I just wish the pads didn't squeal so. Right after I installed them.

 

[CaliMR]

Hmmm maybe I should see if my $11 rotor guy makes them for this car.


It doesn't really apply here, but some guys who race in classes that require OEM style rotors will go looking in junk yards for the oldest, rustiest rotors they can find. They claim the rusty rotors last as long as the cryo ones and resist cracking, and they aren't allowed to upgrade to 2 piece rotors and the other fancy stuff.

 

[LateApex]

Gary - have you tracked with those Frozen Rotors yet? I've been looking into them, interested in what you found out.

 

[cloud9]

Gary - have you tracked with those Frozen Rotors yet? I've been looking into them, interested in what you found out.

Timely question. I was just heading out to the garage to start working on the car. I put them on about a week ago and did an initial bed-in. I've been driving on them for a couple weeks just to get some more heat in them. I stopped by the brake shop where I left my DBAs to be turned yesterday and he showed me how out of round they were. They were ridiculously warped! I've never warped a set before and I obviously put a lot of heat into them. They always crack before they wear out or warp. I'm hoping I just got a bad set of rings, but since DBA is still on backorder and they don't seem to hold up any better than the cheap ones I'm throwing in the towel on them. I did have Bill send me another set of frozen rotors so I have a backup in the trailer.

The guy at the brake shop said he was just at a seminar and they said not to use any type of grease on the inside of the hats. He said it won't compress and you can end up with a small pocket that would keep the rotor from fully seating on thee hub. I have always put a thin layer of anti-seize on mine just like Ford does from the factory, but never had a shudder or warping before. This morning I decided to pull them and clean it off and reinstall before bedding in my new pads for BIR next weekend. Maybe it's paranoia, but I don't want to warp another set. Those DBA rings were new and warped after about the 5th session (2nd day). Of course Road America is at the extreme for brake abuse. I'll know a lot more about the Frozen Rotors after next weekend.

 

[PeteInCT]

Gary - have you tracked with those Frozen Rotors yet? I've been looking into them, interested in what you found out.

I have used Frozen Rotors in the past on my Audi with not so great results. I had found that their rotors (cryo treated of course) lasted just about as long as the stock Audi rotors, maybe even a little less. This may have been a one-off occurrance but my instincts were saying that the steel just wasn't up to snuff compared to other brands. It's totally possible that this was a one-off instance, still I have shyed aware from Frozen rotors since then.

I am currently running Coleman rotors that have been cryo'ed at Diversified Cryogenics (same company that makes Frozen rotors). My experience with those so far have been excellent. I went through 1 set of Pagid RS-29's and a full set of RS-14's (more aggressive than the 29's) and the rotors are showing little sign of wear so far. With the RS-14's I actually ran them down to the backing plate at Watkins Glen. The rotors show no sign wear from the backing plates at all, leading me to believe that the steel of the rotors is much harder than what was used for the backing plates (which seems to be pretty tough stuff).

 

[cloud9]

Gary - have you tracked with those Frozen Rotors yet? I've been looking into them, interested in what you found out.

I have used Frozen Rotors in the past on my Audi with not so great results. I had found that their rotors (cryo treated of course) lasted just about as long as the stock Audi rotors, maybe even a little less. This may have been a one-off occurrance but my instincts were saying that the steel just wasn't up to snuff compared to other brands. It's totally possible that this was a one-off instance, still I have shyed aware from Frozen rotors since then.

I am currently running Coleman rotors that have been cryo'ed at Diversified Cryogenics (same company that makes Frozen rotors). My experience with those so far have been excellent. I went through 1 set of Pagid RS-29's and a full set of RS-14's (more aggressive than the 29's) and the rotors are showing little sign of wear so far. With the RS-14's I actually ran them down to the backing plate at Watkins Glen. The rotors show no sign wear from the backing plates at all, leading me to believe that the steel of the rotors is much harder than what was used for the backing plates (which seems to be pretty tough stuff).

I guess my last experience with DBAs was a terrible one too, but I can't make an assessment on that either. I have gone through a half dozen set of rings with great results, but the last two this year weren't so good. I was getting 15-17 track days using the hellacious DTC70s and this year I got 5 days on the first set (non-cryo) and less than 2 days on the last set (cryo'd) before warping them worse than my collection of hair band vinyl that I stored flat for 20 years!

Bottom line I'm afraid we have heavy cars and if we're aggressive, we're going to be hard on brakes ;D

 

[LateApex]

Dunno, maybe we have an answer, then. If nothing else performs significantly better with minimal drawbacks, I guess I will just load up on OEMs. Kudos to Ford, I guess ???

 

[cloud9]

Dunno, maybe we have an answer, then. If nothing else performs significantly better with minimal drawbacks, I guess I will just load up on OEMs. Kudos to Ford, I guess ???

Definitely worth trying.

 

[VoodooBoss]

Besides the Frozen Rotors another option is the Power Slot one piece rotors. Scott has been running them with no issues that I know of.

http://www.buybrakes.com/p-626-power-slot-cryo-slotted-brake-rotors.aspx

 

[Jimmy Pribble]

Talked to Mark Wilson at Miller earlier this year and I asked him what the race cars needed.

"More brakes," he said.

So, even the big dollar stuff isn't cutting it. Obviously, they are limited by the rules. Just adding a (weakish) data point as a way to subscribe to this interesting thread.

Oh, and I have the highest regard for Paul Weston. I have used his pads (and expertise) for years on my Porsche/Brembo equipped cars.

Jimmy

 

[cloud9]

Talked to Mark Wilson at Miller earlier this year and I asked him what the race cars needed.

"More brakes," he said.

So, even the big dollar stuff isn't cutting it. Obviously, they are limited by the rules. Just adding a (weakish) data point as a way to subscribe to this interesting thread.

Oh, and I have the highest regard for Paul Weston. I have used his pads (and expertise) for years on my Porsche/Brembo equipped cars.

Jimmy

I would concur. That's why I use such an aggressive pad. That said they eat rotors for lunch so will probably just start buying cheaper rotors a' la the OEM weight.