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Grand Am Brakes for the Boss

I’ve been kicking around the idea to install two piece rotors, Disk Brakes Australia said they were going to start selling their two piece disks again but it’s been months.

Kept looking and found Girodisc, two piece floating rotors and yes they have them for the Boss 302/LS, only $800.00 for the set.

So why a two piece floating rotor? What are the benefits?

Two piece floating rotor benefits;

- Reduced pad kick/knock back; rotor flexes and pushes pistons back into caliper = longer pedal travel because you are having to push the piston back out to push the pad against the rotor face.

- Non floating iron rotors when they hot grow in diameter but have differential rates of growth between rotor face and the center of the disc causing coning, think “>”. So no coning.

- Aluminum Hat doesn’t transfer as much heat to the hub prolonging bearing life

- Less unspring weight/rotating mass, car will handle and accelerate better.

- The rotation of the disc causes air to be pumped from the center of the disc, through the vanes, and out through the outside diameter of the disc. This greatly enhances the disc’s ability to dissipate heat. Unlike the non directional vanes in the stock rotors

I’m sure there are more…………….

Then saw they have them for the FR500S/FR500C race cars

OK, race brakes for the Boss 302, not the 302R /302S (4K to 5K a little pricey), so how about the FR500C/FR500S? (Just like they have at Miller Motorsports Park on the Track Attack cars).

Addational Benfits

- Quick change pins for the pads no more hammering out the F^@king caliper pin.

- Real race pads! Well I had real pads but I can use endurance pads, think thicker!

- Thicker pad = a greater thermal barrer and they are about the same price as my current track day pad......so I can go longer ;) on a set of pads that is!

So what’s the damage?

MUSTANG FR500S BREMBO KIT - M-2300-J - $2,950.00 plus shipping

I already have Goodridge Stainless Steel Braided lines so I start to think…….don’t need the whole kit .

What about a la carte?

FR500S FRONT BREMBO BRAKE CALIPERS - M-2320 - $997.00 shipped

FORD RACING MUSTANG FR500C CALIPER BRACKET - M-2134-R - $97 each need two

FORD FR500S Girodisc 2pcFRONT ROTORS (floating) - A1-112 - $1,000.00 plus shipping

So it’ll be about $2,191.00 plus shipping for the rotors and now I can pick my pads.

So gents feast your eyes on my new calipers, next month I get the rotors…….

DSCN0893.jpg

I know you've seen a Brembo caliper in the past.............maybe not so exciting!

FloatingDisc.jpg

The two piece rotors are cool though...............
 
Nice. There's been a couple of other posts about the Girodiscs and they look fantastic. Are those calipers the same ones in this kit?

http://rehagenracingproducts.com/product.sc?productId=1698&categoryId=12
 

steveespo

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What other advantages are there with this set up? Are the pistons in the caliper larger than stock? Are the rotors thicker or same as stock? Is the pad footprint larger than stock. Just trying to justify 2100 for a 14" , 4 piston caliper setup vs a 14", 4 piston caliper setup.

I run DBA 5000 2 piece rotors which are not floating but do have the light weight advantage. Gonna check out the giro disc, if they are floaters than that's is a technical improvement that interests me. When you get them mounted please give us some feed back on how they perform.
Steve
 
steveespo said:
Just trying to justify 2100 for a 14" , 4 piston caliper setup vs a 14", 4 piston caliper setup.

I run DBA 5000 2 piece rotors which are not floating but do have the light weight advantage. Gonna check out the giro disc, if they are floaters than that's is a technical improvement that interests me.

When you get them mounted please give us some fee back on how they perform.
Steve

Steve,

It's really not $2,100.00 if you are going to a two piece rotor it would cost you $800.00 for a pair of Boss 302 rotors, so the difference is about $1,300.00.

What other advantages are there with this set up?

Q: Are the pistons in the caliper larger than stock?

A: No, piston bores are the same, so no booster issues.

Q: Are the rotors thicker or same as stock?

A:If I got this right, I've got notes and I think this is what they are. The braking faces on the Giro Disc rotors average .367" thick with a center air gap of .515". The Brembos have average braking face thickness of .335" and air gap of .585". But remember, the Giro Disc rotors are directionally vaned and will pump more cooling air than the non-directional OEM Brembos.

Q: Is the pad footprint larger than stock.

A: No, this makes is plug and play because you are not messing with the brake bias. ??Brake Toque?? Right?

Question Not Asked: What about pad thickness?

A: The stock Brembo pad thickness is around 15mm 8-9mm; yes I said around different manufactures different thickness. The "Race Calipers" I'm told are 25mm 18mm. The pad price is very close 10-15 dollars more or less so you can get at least an extra weekend out for a set of pads.

I measured the gap, in between the pistons on the caliper it’s 72mm or so, anyone got a wheel off can you measure the gap on the stock ones?
 
What is the thickness of the OEM pad? Is it really 15mm? I only have 5mm left, I had assumed that was about 50% based on other cars
 

ArizonaBOSS

Because racecar.
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Great info. The Girodiscs will line up properly (hat offset) with the 500S calipers? I may do this as well, if so.........................

Also--what is the FMSI shape number for the 500S pads? I would like to start looking at compounds and prices.

Lastly--you can probably sell your stock brembos to someone on TMS looking to upgrade their GT.
 

PeteInCT

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Another 2 pc rotor source is Coleman, who I am told actually makes the rotors for Girodisc (not the top hats, that's made by Girodisc). I use a full Coleman setup up front and am swicth the rears out as soon as my DBA4000's wear through.

You can get the Coleman's for the Boss with a Cryo treatment (done by Diversified Cryogenics) through Paul from Weston Motorsports, $1166 delivered to me in CT:

Paul Weston
Weston MotorSports
888 558 0631 - office
813 486 1531 - cell
 
Ok I bit the bullet and went for the 302r/s brakes the larger master cylinder and the race abs module .My hope is to make it thru a track day or 2 with out bleeding my brakes.I am sick of a soft pedal.I am told by Capaldi racing that my problems will be solved .I hope so it cost a small fortune.I'll let you guys know in a week or so
 
Boss_302 said:
CaliMR said:
What is the thickness of the OEM pad? Is it really 15mm? I only have 5mm left, I had assumed that was about 50% based on other cars

Go to Hawk Performance http://www.hawkperformance.com/parts/ and look it up (you'll have to search by the GT500 becase they don't list the Bos 302 fronts) they list the front pad thickness at .585 so thats 14.859 mm.

I just went out and measured the pad thickness on my OEM pads they have maybe 500 miles ont them; 9mm. So I'm guessing the aftermarket pads are thicker.
 
So what are the advantages of the FR500S M-2320 calipers? Improved stopping power, better heat transfer for reduced fading, greater service life or just thicker pads? The stock calipers/pads are so easy to change that's a wash for me. I have a pair of new (take offs) front and rear pads in my garage and I'll get them out and measure them tomorrow.

Any new info of the upcoming FR Boss brake upgrade package? From what I'm reading on the 2013 GT500 brakes they may not be an improvement. I looked at one carefully the other day and while they are six piston calipers they don't look any beefier. Also the GT500 uses larger rear discs but the calipers looks to be the same one used on all the S197 cars.
 
Where do you get the extra 10mm to insert 25mm pads on each side? Is the caliper thicker requiring more wheel clearance? I'm sure they'd still clear my Enkeis, but no way they'd clear the stock or LS wheels.
 
ArizonaGT said:
Great info. The Girodiscs will line up properly (hat offset) with the 500S calipers? I may do this as well, if so.........................

Also--what is the FMSI shape number for the 500S pads? I would like to start looking at compounds and prices.

Lastly--you can probably sell your stock brembos to someone on TMS looking to upgrade their GT.

I was told by the folks at Giro Disc and Leo Capaldi Racing the following;

Ford Racing had part numbers galore for hats/rotors and the caliper mounting brackets for the FR500C and then more part numbers for the FR500S.

What it boiled down to was Multimatic built the FR500C's for Ford and made up in house the original hats, caliper mounting brackets etc just for the "Boy Racer"

Then Ford Racing built up in house the FR500S and sourced parts from Brembo.

FMSI Shape is D810 / D968

The caliper is the B/H family of Brembo calipers.
The pads pad set is 107.4865.80 HP 1000
Rotor family is 80 - Size 355 mm diameter 32mm thick - Part No. 09.5759.13/23

caliperinfo.jpg

5 DOT 0 said:
So what are the advantages of the FR500S M-2320 calipers?

So, from what I have gathered the caliper is from the Gran Turismo range a step up from the OME but a Step down from the stuff that Rotetman is getting.
 

ArizonaBOSS

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5 DOT 0 said:
From what I'm reading on the 2013 GT500 brakes they may not be an improvement. I looked at one carefully the other day and while they are six piston calipers they don't look any beefier. Also the GT500 uses larger rear discs but the calipers looks to be the same one used on all the S197 cars.

The '13 GT500s are a bit of a conundrum. I have held them in my hands and they are PRETTY. They are also monoblocks, which means the caliper will flex a lot less than what we have on our car under pressure. The downside is that you are now moving 12 pistons as opposed to 8, without increasing the size of the master cylinder, which may reduce pedal feel/control.

The 4-piston monoblocks are supposed to be super effective due to the lack of flex--so we just need to get some PNs for these; I'm pretty sure this is what comes in the "trophy" brake kits.
 
PeteInCT said:
They also use an upgraded master cylinder.
Yes the 302 R/S do and that's what roketman ordered.

It will be interesting to see what FR comes out with. The GT500 seemed like an easy upgrade path but I'm not so sure now. Maybe the larger rear rotors will be an option.

Doug thanks for gathering up all that info, it's very useful and I'm sure those calipers will be a nice improvement over stock. The price is very reasonable too.

I'm still stuck on the rotors. I thought I'd go with the Girodisc but now that you stated Coleman makes their rings I'm thinking about the FTB rotors again. They just had a price increase though. What would be interesting to find out is if the rings are all the same with slightly different slots applied to them. If so go with the least expensive. So Coleman makes Coleman, FTB and Girodisc rings.
 

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