Ford Mustang Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
8,561 Posts
Discussion Starter #1
Looking around for some used R calipers or Focus RS brembos. Anyone know the piston sizes in these?

What is the ideal MC to use with the sn95 cobra rear disks (38mm piston) and the sn95 booster. Basically an m2300k kit with the brembos

I actually have the 94-95 cobra, 93 cobra and 94-95 gt/v6 mc....so I have all three popular ones available.
 

·
Registered
Joined
·
8,561 Posts
Discussion Starter #3
Thanks,

That puts piston surface area at 9100mm^2 for both sides combined.

The 94-98GT calipers are the next biggest OEM front at 6842mm^2 for both fronts..and those use the 1 1/16" MC.

So what to use?
 

·
Registered
Joined
·
127 Posts
The 03/04 Cobra Master cylinders have the end bleeder which really comes in handy if you happen to get air in the very tipped cylinder during brake work or bleeding.

While there are others that are functional with this caliper set up, it's nice to have that bleeder, rather than have to remove the master and bench bleed that trapped air out.

Even the 2000 Cobra R cars did not have the extra bleeder.
If I was building an early SN95, that is what I would put on mine, 03/04 Cobra master cylinder FTW.
 

·
Registered
Joined
·
8,561 Posts
Discussion Starter #5
The 03/04 Cobra Master cylinders have the end bleeder which really comes in handy if you happen to get air in the very tipped cylinder during brake work or bleeding.

While there are others that are functional with this caliper set up, it's nice to have that bleeder, rather than have to remove the master and bench bleed that trapped air out.

Even the 2000 Cobra R cars did not have the extra bleeder.
If I was building an early SN95, that is what I would put on mine, 03/04 Cobra master cylinder FTW.

However, I have an '88, with Cobra brakes. Need to use a vacuum booster mc.
 

·
Registered
Joined
·
127 Posts

·
Registered
Joined
·
683 Posts
Thanks,

That puts piston surface area at 9100mm^2 for both sides combined.

The 94-98GT calipers are the next biggest OEM front at 6842mm^2 for both fronts..and those use the 1 1/16" MC.

So what to use?
When calculating piston area (for M/C sizing)for calipers with pistons on each (opposing) side of the caliper you disregard one side. The piston area of the Brembo Cobra R caliper is ~ 2275mm^2 per caliper.
 

·
Registered
Joined
·
8,561 Posts
Discussion Starter #8
Awesome

so 2275x2 = 4550 mm^2


94-98 Cobra calipers are 4536mm^2. So with the 38mm rears, they use the 15/16" MC.

So since i already have that MC...i'm good to go! Thanks
 

·
Registered
Joined
·
77 Posts
Mustang5L5, I was the Mustang brake development engineer at Ford that brought the Brembo caliper in to Ford. I had it ready for the 1995 Cobra-R however the program couldn't justify the expense (yeah, I know...). That's why they clear the '95 R wheels so nicely. The chief engineer at SVE promised me that he would put them on the next Cobra-R which we did for 2000. That 13" brake was 5 years out of date by that point and the 2000-R really should have had a 14" set up. I did all of the development work for that caliper with the 1" master cylinder which ultimately was the size of the '95-R master cylinder. The piston area of the 36/40mm 2000-R caliper is about the same as the twin 38mm's of the '94-'98 Cobras. I like the system with the 1" as it gives you great feel and flexibility in friction material choice (you are not required to run high friction pads). The 1 1/16" will have even shorter travel however may be difficult to lock up at times. I would definitely put the 1" on.

Rob
 

·
Registered
Joined
·
8,561 Posts
Discussion Starter #10
Hi Rob, thanks for the reply. I guess i went right to the top source for the info I needed. That helps a lot. Right now I already have the 1" bore MC on the car (running the 40.5mm Mach 1 calipers up front). I just happened to have the 15/16" and the 1 1/16" MC as well handy...why i was trying to see which would be ideal.


Can I ask a question though. If the Brembo is similar to the 94-98 Cobra caliper in terms of piston area, why did the 94-95 Cobra get the 15/16" MC while the '95R got the 1" bore? Is it more of a race vs street thing? I figure the average street-going Cobra driver would want the slightly softer pedal?? That's just an assumption on my part though.

I'm going more for a street/weekend type of setup. I gotta admit, my desire to put the Brembos on is simply to have a big caliper poking out behind my wheels. I have no intention of racing...for now. I'll stick with the 1" MC that is in there now though. ( Thanks for your input.
 

·
Registered
Joined
·
1,087 Posts
FWIW: im running the same setup with a 1" MC and it feels great! im gonna start playing around with brake pad material for the street as there are times i feel i want more initial bite though... Running factory pads for now... it'll be an easy fix.

I never new that ford was looking into using brembo's for the 95R... and always wondered why they didnt go with a 14" setup for 00R... thanks for the info...
 

·
Registered
Joined
·
77 Posts
Hi Mike.

You are basically correct with the reasoning for the 15/16" on the "street" Cobra. I had started off all of my development work with the 1" master cylinder for the Cobra application. It sure felt awesome! The change to the 15/16" came kind of late in the midst of development. I was driving down the main road outside of our Dearborn proving grounds one morning and (with no traffic around) I decided to do a full ABS stop from about 45mph. I was quite surprised when I was not able to lock up the brakes. The conditions at the time were fairly green pads with about 30 miles on them, fairly cold brakes and the 1" master cylinder. I decided that the largest brakes on a Ford passenger car should be able to do a full ABS stop under those conditions. The JBICP26 friction material was carried over straight from the Corvette and while proven to be an okay material all around, it is a semi-metallic which does lose some friction when cold. They are also more sensitive to burnishing in than other materials I have worked with. There are other factors to consider such as altitude which would only make things worse. So, late in the program I changed down to the 15/16" master cylinder believing it was the best compromise for all around use. Having had so much experience and test data with the 1" went to good use though, as it was the perfect size for the track oriented '93 and '95 Cobra-R applications.

Yes, the 13" Brembo application on the 2000-R was a fun project and would have been ideal for the '95 R that it was developed and intended for. We had Brembo permanently modify the prototype casting tool for the Viper caliper to create the 2000-R caliper. I even had the hose attachment point moved to the exact coordinates as the PBR application so it was an easy bolt-on. While the brake doesn't run any cooler than the PBR (since they both use the same 13" rotor) it does a great job with managing tapered wear providing consistent pedal feel. It would have been awesome back in '95 and is still a great bang for the buck upgrade.
 

·
Registered
Joined
·
8,561 Posts
Discussion Starter #13
Rob, thanks for the info and development history. I actually envy you for being in a position to take part in such development. Alas, I am in a different field of engineering, without anything newly as exciting to test. Oh well.

Thanks again
 

·
Registered
Joined
·
17,035 Posts
Rob and Prez any street pad recommendations for the 00'R brembo or what is your experience with certain pads. You said not much aggressive is needed. Is a Hawk HPS too much for a 93 fox with a 1" bore cobra M/C.

I just picked up a fairly new kit with less than 5k miles and the guy never installed the rotors, he used his stockers. I am sorta bummed they won't work with my BBS wheels, but I have a set of Ford Racing 10ths anny. 17x9 to use instead.
 
1 - 14 of 14 Posts
Top