Tech Clarification: 99+ Cobra/Bullet Calipers vs Early Cobra

[Lewis Tanner]

Front calipers may be updated/backdated from any car of the same manufacturer listed in Section 4. Eligible Manufacturers/Models, and shall utilize either 2 non opposed pistons no larger than 38mm in diameter or a single piston no larger than 76mm in diameter with the following exceptions listed below:

a. GM vehicles may use stock 98+ Camaro/Firebird 44mm dual piston calipers

b. Ford vehicles may use stock 99+ non Cobra 44.5mm dual piston calipers

 

 

The earlier 38mm PBR/COBRA are becoming scarce as they were only around for a few years and the new Cobras and Bullet Mustangs that use the PBR "COBRA" calipers have had 40mm pistons since 1999. The part numbers cross reference for the things so you can't be guaranteed you're going to get the 38mm units if you order a set of reman calipers from a chain store or the like - you just get a set of PBR calipers that say "COBRA" on them. Most people selling the things on the internet just call them "COBRA" calipers and have little idea of the piston size. I honestly don't know which ones I have. Was excluding their use an oversight in the rules or is there a reason the 99+ Cobra calipers with the 40mm pistons are not eligible? I don't think there's a performance difference but I've been wrong before (once).

[King Matt1548534716]

As Lewis notes, the 40mm caliper has superceded the 38mm version. I'm sure if you buy a new set from Ford Racing, which is the most economical option out there for new calipers, that's what you'll get. They are also used on Mach 1s, but not marked "Cobra." You can still get the 38mm calipers new from Baer, but they are more expensive.

 

On a related note, I thought that the single-piston PBR calipers that Baer sells as part of its A Sedan rear brake setup used to be legal for the Mustangs, but in the latest 2006 rules revision, it does not appear to be covered in the fine print. These are the same calipers that are legal for update/backdate on the GM cars. Are they allowed on Mustangs?

[mitchntx1548534714]

So a 38mm dual piston caliper is legal on a Mustang?

 

hmmmm ....

[Lewis Tanner]

So a 38mm dual piston caliper is legal on a Mustang?

 

hmmmm ....

 

The 96-98 (and I think part of 99) Cobra had the dual 38mm caliper. After that, the Cobra, Mach 1, and Bullet all run the same caliper with 40mm bores.

 

 

 

Click here for picture of C4 Caliper on a Mustang.

 

 

You can also run the 1996 Corvette Gran Sport calipers (maybe all C4, I don't know), as they are the same casting as the 96-98 Cobras and actually meet the letter of the rules, unlike the 99+ Mustang Cobra calipers. I had those on my old Saleen and it drew quite a lot of attention.

Edited December 9, 2005 by Guest

[mitchntx1548534714]

Interesting ... A Corvette caliper is perfectly acceptable on Mustangs as a performance upgrade ...

 

Interesting, indeed ...

[bsim]

That's the C4 Corvette PBR caliper - same as the Baer kit for the Camaros. Same as 1LE Camaro too...

[mitchntx1548534714]

What's the cost of those C4 dual 38mm piston calipers?

[Al F.]

I dont think its so much of an intentional decision as much as a lack of interest situation. Personally I dont have a problem with the slightly increased piston size of the later model calipers as long as that is truly the only difference. Let me look into that.

[Lewis Tanner]

What's the cost of those C4 dual 38mm piston calipers?

 

I think I paid $160 for the set, new in the box, on EBAY.

 

Thanks, Al. I'd hate to see someone get to nationals and have a legitimate protest lodged against them for something like this.

[Keith]

Those are nice brake setups for sure but I have found that with the local parts store $62 reman LS1 fronts and Brembo OE stock rotors, I can invoke lockup at will and not have fade all day.

 

These tires don't require much brake...

[y5e06]

Just FYI, the J55 13" brake package was an option on C4's up through '94. '95-'96 J55 was standard on ALL cars, not just GS. So you can get them cheaper if you don't order the pimpy GS calipers as others will not have the paint/lettering. Standard C4's had 12" brakes up to '95. Don't bother with pre '89 as they had different design.

12" rotors were only ~1' thick and 13" were 1.25" thick if I recall, so you don't want to use the 12" calipers either, for cut down cobra rotor applications

[Glenn]

mustangs are not allowed to run the 1.25" rotor, they are limited to the 1.125".

 

i also assume no one will have a problem w/ me running a C5 caliper on my 4th gen now.

[OldCMC17]

I ground off my COBRA PBR's and etched FERRARI on them. Makes me feel better and I KNOW I stop better due to the name even though it's the same manufacturer.

[y5e06]

mustangs are not allowed to run the 1.25" rotor, they are limited to the 1.125".

 

i also assume no one will have a problem w/ me running a C5 caliper on my 4th gen now.

 

I think I was mistaken, the J55's are 13x1.125. Anyway, my post was in reference to using a c4 caliper in place of the mustang unit, assuming it was indeed identical. Of course the C5 calipers are not identical to the F-body units.

I don't recall if the GS pieces were just painted w/ a sticker or had actual raised cast/machined lettering. In any case the ZR1 or optional J55 calipers do not.

[Lewis Tanner]

i also assume no one will have a problem w/ me running a C5 caliper on my 4th gen now.

 

Why is that? Are the C5 calipers exactly the same as the currently described legal caliper? The Cobra/PBR caliper is about the only upgrade caliper we can use on the Mustang, and the factory 76mm single piston calipers just don't make the grade. I've seen them fold up under moderate OT use with a hot set of pads.

 

The following calipers are, aside from the discontunued 38mm/superceded 40mm difference, exactly the same units with different lettering machined on the caliper face:

 

1) 1996-98 Mustang Cobra PBR 38mm twin piston

2) Corvette C4 PBR 38mm twin piston

3) Baer PBR 38mm twin piston

4) 1999-Current Mustang Cobra PBR 40mm twin piston

5) 2001/2004 Bullet Mustang PBR 40mm twin piston

6) 2003/2004 Mustang Mach 1 PBR 40mm twin piston

 

The above are the same caliper aside from the piston bores, use the same pads, share the same mounting brackets, use the same rotors, and function exactly the same as one another from a performance standpoint. They are substitutions for one another so long as the piston size is the same from left to right. As the rules currently read, only items 1,2, and 3 in the above list are legal for use on a CMC car, but 4,5, and 6 are equal items.

 

As far as I know, the C5 caliper is not the same as any currently legal caliper and I've got no idea why you're trying to suggest that clarifying the rules regarding interchangable calipers on a Mustang should in any way allow you to put a completely different caliper on your car unless you're just trying to be a pain and cause controversy in the name of making life more difficult for those of us that wish to follow the rules. So what gives, Glenn? Why, other than to try and make things controversial for no reason, would you even try to conflate the use of any of the above calipers on a Mustang with your use of a completely different caliper on your Camaro?

 

The bottom line here is that the rules currently state 38mm and were clearly written to accommodate the PBR/Cobra caliper, but the specs on the current production PBR/Cobra caliper have changed. For all I know, Tony and Al aren't aware of this change and simply don't realize that it provides a technical loophole for someone to use if they really want to protest a car.

Edited December 9, 2005 by Guest

[Glenn]

C5 calipers have a twin 40mm piston.

98 F-body calipers have a twin 44mm piston.

myself and another person asked if we could use the C5 caliper. we were told no. the coment was something to the effect of "do you know how much flack i'm gonna get from the ford guys for allowing the F-body guys to use a Corvette caliper?"

now i'm seeing that the ford guys are being allowed to use what we were told we couldnt - a caliper that said Corvette.

 

for the record, i'm not against you using them, i'm agianst you being allowed and me not being allowed.

it was explained to "the powers that be" the cost difference ($20 each) and piston size difference (4mm smaller). it uses the same F-body pad and will bolt up to the F-body bracket. i ran this set-up on my 98 w/ C5 rotors for a short time till i upgraded to the Porsche stuff. the C5 caliper is made using a much better casting method and had the same stiffining ribs across the top , just like the ones you are using, that the currently leagal 98-02 f-body calipers don not have. like the ford cars, the f-body guys have seen caliper spread. just ask mitch and nick (4th gen and 3rd gen).

not sure why your so quick to jump my ass.

[Lewis Tanner]

now i'm seeing that the ford guys are being allowed to use what we were told we couldnt - a caliper that said Corvette.

 

The point you're so eloquently missing is the fact that the only difference between the Cobra caliper and the C4 Corvette caliper is the lettering on the face. They're the same caliper. The C5 caliper is completely different from anything you can put on the Camaro.

 

for the record, i'm not against you using them, i'm agianst you being allowed and me not being allowed.

 

Allowed to do what? Run the exact same caliper as the rules state we can use? How you equate using a completely different caliper design with using an identical one is truly beyond me, Glenn. You're just trying to piss on the parade here and you know it. You can't seriously be trying to tell me otherwise.

 

the C5 caliper is made using a much better casting method and had the same stiffining ribs across the top , just like the ones you are using

 

The C5 calipers are NOT just like the ones pictured above. You're missing the point entirely and don't have a clue what you're talking about. There is not one physical difference between the calipers I listed above aside from the piston bore in the later Mustang variants. No casting difference, no difference in stiffening ribs, no nothing. There is no "just like the ones I'm using" about it. The 6 calipers I listed are identical while the C5 caliper, as even you point out, is a significant performance upgrade due to casting methods and design differences.

 

Do you understand that? If so, why are you trying to turn a simple clarification of the rules into something that allows you to run a completely different, substantially upgraded component?

 

 

not sure why your so quick to jump my ass.

 

Because you're making a stink over what should be a simple issue just because you feel like it. You don't like the fact that you can't run an upgraded, higher performance caliper and you're grabbing at straws and using a completely unfounded argument in another attempt at being allowed to do so after being told you can't. You're taking a simple technical issue that doesn't affect you in any manner whatsoever and trying to make things more difficult than they need to be for others for some reason and yes, I'll jump your ass for it.

 

The rules as they sit allow you to use the PBR 38mm caliper from a Mustang, Baer, or even the Corvette C4 on your Camaro, so I don't see how this has any bearing on the Corvette C5 caliper in any way>

Edited December 9, 2005 by Guest

[bsim]

FWIW - I've heard (from Mike P.) that C5 calipers will bolt right on to the 98+ Camaro uprights. NO adapter needed ala C4.

 

The C5 calipers have smaller bores than the C4 calipers. The C5 calipers have thicker 'tabs' on the outside clamping edge than the LS1's, and have bigger cooling fins across the top. They would be less prone to the 'spread' and resulting pad wear (cost issue).

 

I've considered switching BACK to the LT1 setup on my 4th gen, THEN going with the Baer system, as I never had spread issues with the PBRs (C4). However, the ~$800 cost is keeping me from doing so.

 

Simply replacing my current calipers with C5's would cost 1/3 less, and achieve the same smaller bore size/stonger caliper goal.

[Glenn]

Lewis, give me a call. Adam can get you my number. i'm not sure why your pissed @ me.

my point is the C5 and F-body caliper that we currently run are the same, look the same, and are both PBR's. but i was told we couldnt use them due to the word "CORVETTE" on them. i'm all for you being able to run those caliper you have.

you have a problem w/ me running a caliper that has smaller pistons cause it came from a C5? they are the same other than the piston size.

[Glenn]

oh, and i've done my best to turn off my "Parade Pissing Machine".

[Glenn]

You don't like the fact that you can't run an upgraded, higher performance caliper and you're grabbing at straws and using a completely unfounded argument in another attempt at being allowed to do so after being told you can't. You're taking a simple technical issue that doesn't affect you in any manner whatsoever and trying to make things more difficult than they need to be for others for some reason and yes, I'll jump your ass for it.

 

i just want to be able to run the same quality caliper as you have. i've been working on this longer than you know.

w/ 50lbs less required wieght, you have less you worry about than i do. i need a caliper that is less prone to flex. is that to much to ask?

like i said before, we are allowed to run a twin 44mm pistons. i want to drop down to twin 40mm pistons w/ a caliper that will use: the f-body pad & caliper mount, almost the same cost, both made by PBR and look 99% identical to what we have now.

where is the rub here? i was told no for no other reason than because it said "Corvette" on it. you were told yes even though it says "Corvette".

[Guest]

Everything Glenn is saying is correct.

 

The C5 caliper has very similar dimensions to the LS1 caliper except for the piston size and strengthening ribs.

 

I'm not trying to be inflammatory here but if Mustang guys spread stock calipers and have the "Cobra" allowance, why can't F-body guys have the same allowance with C5 calipers. Hell, C5 calipers even bolt up to the same abutment [sp?] bracket and use the same pads without modification.

 

[edit] In addition, it wouldn't increase cost by much at all. Use the LS1 calipers until you spread them, then buy C5 calipers instead. The extra $40 initial cost will pay for itself very quickly when Kraft LS1 "easy spread" calipers cost $60/each.

Edited December 9, 2005 by Guest

[Lewis Tanner]

you have a problem w/ me running a caliper that has smaller pistons cause it came from a C5? they are the same other than the piston size.

 

No, they're not the same. As you pointed out, there are significant differences in casting and design, resulting in a higher performance caliper. There are no performance differences between the 6 calipers I listed, while there is a performance difference between the F-Body and C-5 Calipers.

 

 

i just want to be able to run the same quality caliper as you have.

 

YOU CAN RUN THE PBR/COBRA CALIPER ON YOUR CAMARO- EVEN THE C4 UNITS. THE RULES STATE THIS TO BE TRUE AND NOBODY IS STOPPING YOU FROM DOING IT, GLENN (or anyone else).

 

The "rub" here is that you're trying to equate clarifying a production change in a legal caliper with the introduction of a completely different caliper and don't seem to think that there's anything wrong with it. If you think that the PBR/Cobra calipers are that significant of a performance upgrade, you're welcome to run them on your car. I can tell you that they are, from a racing perspective, rather marginal and prone to quite a lot of flex, but are a hell of a lot better than the 76mm single piston that came stock on the Mustang. Allowing the 40mm PBR calipers for all competitors would in no way change the balance of the rules because there is no performance upgrade whatsoever - allowing the C5 calipers on a Camaro is a performance upgrade from the current ruleset. There are two completely different issues here, and if you want to argue for the stinking C5 caliper, do it in your own thread.

 

 

Nape - have you ever even seen the stock units on a Mustang? They don't spread - they fail. They literally taco out and melt from the heat of the little rotors that you have to run with them (10" or so) trying to stop a 3100 lb Mustang. The PBR twin piston is just as prone to spreading as the F-body kit, IMO.

[Glenn]

so you guys have 6 calipers that are a bolt on, and i have 1. any reason to allow me a 2nd option?

you guys have the pick of the litter.

i'm gonna guess that the only difference between your C4 caliper and the C5 caliper is the mounting ears. i have no tech on hand to back this up, but i'm thinking thats the case. so the real diffence is you can bolt up the C4 and i can bolt up the C5, but not the other way around.

 

and i didnt say they had a diffent casting design, i said casting method. i believe they are vacuum cast and not gravity cast (both the C4 and C5 use this method).

[Lewis Tanner]

Everything Glenn is saying is correct.

 

No it isn't. He's saying that the C4 PBR caliper is somehow a performance upgrade even though it's the exact same caliper from the same foundry as every other PBR 38mm twin piston caliper.