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

[Lewis Tanner]

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

 

You can run any of those 6 calipers on your car. Call Baer and get the brackets. If a Mustang owner wants to run them, they need to buy brackets as well.

 

 

you guys have the pick of the litter.

 

How so? You can run the exact same calipers! Hell, you can run the calipers from a Mustang Cobra on your car if you want because Baer makes the bracket for them!

 

 

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.

 

Wrong. 100% categorically wrong. They are a completely different caliper sharing no common dimensions whatsoever. There is not one thing they share except for the fact that they have two pistions. And that's the entire point of this discussion. You don't seem to be even attempting to understand that the PBR caliper on the C4 and the PBR caliper on the Mustang Cobra are identical in every way, shape and form other than the lettering on the face, while the C5 caliper is a completely different design. My problem with you here is you're trying to argue a point that even you admit you have no technical data whatsoever to support, while I know through fact and experience what I'm talking about.

 

I've made a prototype bracket to mount the C5 caliper on a Mustang spindle - had the drawings made and a bracket printed on a 3D wax printer, then mounted the units on my car! I can tell you that the C4 and C5 calipers are in no way similar. The C4 calipers are the Mustang Cobra calipers, it's that simple.

 

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).

 

They do have a different design - even you pointed out that they are less prone to flex due to the addition of more ribs along the top.

Edited December 9, 2005 by Guest

[Glenn]

totally done here.

glad you had an open mind.

cool off and think about what i typed.

[Guest]

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.

 

That's scary, no wonder you guys need PBRs.

 

I haven't heard of problems as wide spread as LS1s about the PBR calipers. As a matter of fact, I'm planning to run the PBRs on my 3rd gen as soon as I finish piecing it together. I had most of the parts together to run an LS1 setup with C5 calipers until I realised they aren't legal. Knowing that, I decided to switch to the PBR (known as C4HD in 3rd gen land) setup with a 12" rotor. It sucks to have to turn down rotors (as you Mustang guys know) vs. off the shelf LS1 rotors, but this setup has been working well for a few people so far.

[Lewis Tanner]

After all that, can we get a response to the original rules question?

 

Can the 40mm PBR calipers that superceed the original 38mm design be used or do we have to go junkyard diving for our upgrade from the stock units? If they can be used, will a tech clarification on the rules be made so there isn't a way to protest someone using the 40mm units on a technicality?

 

The funny thing here is the C4 units are legal, while the 2000+ Cobra/Bullit/Mach 1 units aren't!

[y5e06]

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...

 

checking part numbers through Oreilly's (yes, I know. not the offical way to verify part #'s) the machined GS (Z16), non-machined J55, and '94-'98 cobra calipers reference different part numbers. Most likely due to the 'Corvette', 'Cobra', and standard J66 machining differences. So are they identical? I guess not.... due to the machining. Excerpt of the rules state:

 

4. 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:...

 

my interpretation is that it says you can only use calipers sourced from those listed in section 4, and then goes on to say that they can't be larger than 38mm (dual) or 76mm (single). It does not seem to say that you can use those from section 4. OR those no larger than 38mm/76mm. i.e. can't use the vette sourced units.

 

by the way, are the cobra calipers machined w/ 'COBRA'? I'm just assuming they are. Did Saleen or Rousch models come with aftermarket or upgraded calipers? could they be had w/ the non-machined calipers? if so then that is your loophole as section 4 includes saleen & rousch cars.

[Adam Ginsberg]

Actually, the Ford crowd only has 2 caliper options when using a PBR setup. The first 3 Lewis listed:

 

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

2) Corvette C4 PBR 38mm twin piston

3) Baer PBR 38mm twin piston

 

Are all the same caliper. No casting differences, no piston size differences. The only difference is lettering.

 

The last 3 listed:

 

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

 

Are also ALL the same caliper. No casting differences, no piston size differences. The only difference is lettering, and color ( on the Bullitt, and possibly the Mach 1 models ).

 

The 1LE calipers are the SAME UNITS as the first three....and the GM guys are permitted to run them.

 

ALL of the calipers listed above use the same pad outline - D412.

 

The C5 Corvette pad outline is different - D731.

 

Part numbers from various parts houses ( AutoZone, O'Reilleys, etc ) will be different. The letters/symbols ( COBRA, CORVETTE and the running horse ) are cast into the caliper, then machined.

 

The C4 Corvette caliper has NO lettering on it at all ( I used a set of those on my street car for years ).

Edited December 9, 2005 by Guest

[Lewis Tanner]

4. 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:

 

my interpretation is that it says you can only use calipers sourced from those listed in section 4, and then goes on to say that they can't be larger than 38mm (dual) or 76mm (single). It does not seem to say that you can use those from section 4. OR those no larger than 38mm/76mm. i.e. can't use the vette sourced units.

 

I agree completely with that interpretation. If you want to follow the letter of the rules, using the calipers machined with the word "CORVETTE" on their face would not be legal. My original posting with the calipers on my old street car was just to show that they were, in fact, the same caliper. I don't plan on running them, and would suggest that others don't either. I will, in fairness of complete disclosure, admit that I bought my banjo bolts for my brake line/caliper interface from the GM parts counter as they want about $7 less per bolt than ford and it's not a special order.

 

by the way, are the cobra calipers machined w/ 'COBRA'? I'm just assuming they are. Did Saleen or Rousch models come with aftermarket or upgraded calipers? could they be had w/ the non-machined calipers? if so then that is your loophole as section 4 includes saleen & rousch cars.

 

Cobra calipers are machined "cobra".

 

Saleen didn't come with the PBR twin pistions. It was either stock or the big honking 6 pistons. I don't know about roush, but they may have run the non machined version of the caliper.

 

Baer and diskbrakesrus sell a flat faced version of the caliper.

 

For the record:

 

 

C4, Cobra, Mach 1, Bullit PBR Caliper.

 

 

C5 caliper.

[Lewis Tanner]

totally done here.

glad you had an open mind.

cool off and think about what i typed.

 

There's no "open mind" to have here, Glenn. You came to the table with an argument based on conjecture and speculation and not fact, and I called you out on it. No hard feelings, but you should really research a subject like this before trying to use opinion as a defense against documented and verifiable facts. It makes life a lot easier.

[bsim]

4. Front calipers may be updated/backdated from any car of the same manufacturer... listed in Section 4.

NO Corvette labled calipers on Fords, no Bullit (or whatever) labeled calipers on GMs.

 

Nit-picky I know - but if you wanna jump into that mire, let's go all the way.

 

...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

 

So, no 6 pistons. Where did that come from anyway?

 

Also, 38mm is the preferred size, there are exceptions for 44mm GM and 44.5 Ford. BTW, if they're 'identical', why the bore size difference?

 

According to these rules, the C5 calipers are legal for Camaros since:

1. They are from the same manufacturer (conforming to 8.35.9.4)

2. They follow the piston diameter requirements (conforming to 8.35.9.4)

 

We don't even have to get into the 'exceptions' in 8.35.9.4.

[rocketman]

So what is the OFFICIAL answer to the ORIGINAL question please? TIA.

 

edited: official answer

[King Matt1548534716]

Should I just start a new thread with my PBR rear caliper question?

[Adam Ginsberg]

Brad, I think you are getting a bit corn-fused about the various brake calipers.

 

...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

 

Item B listed above is for the NON-Cobra calipers ( 1999-2004 Mustang GT calipers ). In 1999, Ford changed calipers on the GT's.

 

The GT caliper is a PBR, but is not identical to the Cobra unit. No one advocated using a 6-piston caliper.

 

Also.....the C5 caliper may come from the same manufacturer, but clearly do not come from the same make of car.

 

8.3. Update/Backdate Non-body Components

Non-body components may be updated/backdated within cars of the same manufacturer on the eligible manufacturers/models list (i.e. 1982-92 GM Early Components may NOT be interchanged with 1993-97 GM Late Components). Unless noted elsewhere in these rules.

 

8.35.9, subsection 4 says you can update/backdate within the manufacturer listed in section 4 - and the Corvette is NOT listed in section 4, nor noted elsewhere in the rules.

 

2006 CMC rules, Section 4:

 

4. ELIGIBLE MANUFACTURERS/MODELS

 

Manufacturers:

 

Ford Motor Company

Eligible Ford makes and models:

1979-95 Ford Mustang 5.0 V8 (Cobra models excluded)

1979-86 Mercury Capri 5.0 V8

1996-04 Ford Mustang 4.6 V8 (Cobra models excluded)

 

General Motors (Early GM)

Eligible Early GM makes and models:

1982-92 Chevrolet Camaro (all submodels with 5.0L V8 motors eg – RS, Z28 etc)

1982-92 (all submodels with 5.0L V8 motors eg Formula, Trans-Am, WS6 etc)

 

General Motors (Late GM)

Eligible Late GM makes and models with 5.7L V8 motors

1993-97 Chevrolet Camaro Z28 excluding SS

1993-97 Pontiac Formula, Trans-Am, excluding WS6

 

Even though the C4 Corvette caliper is identical to the Cobra unit, except for lettering, it can't be used on the Ford vehicles. The same is true for the GM cars - they can't use a caliper with the word "COBRA" emblazoned on it. Kinda silly since they are the same caliper, but it is what it is.....

 

As for the updated 40mm Cobra/PBR caliper.....please be patient while we work out an answer.

[Guest]

8.35.9, subsection 4 says you can update/backdate within the manufacturer listed in section 4 - and the Corvette is NOT listed in section 4, nor noted elsewhere in the rules.

 

You're shitting me... damn it. I usually use periods as a punctuation mark to end a statement

 

To clarify, "Front calipers may be updated/backdated from any car of the same manufacturer listed in Section 4." is not the end of the statement?

 

So, basically I'm limited to LS1 or 1LE brakes on a 3rd gen?

Edited December 9, 2005 by Guest

[jeffburch]

Thanks LT for bringing this topic to light.

I was eyeballing Mach 1 (blank side) calipers on Ebay.

I'm a big dummy and didn't realize the bore difference.

 

If this doesnt pan to the favor of all users of these,

maybe we can trade calipers.

My Baers for your C4HD's

I do not look forward to dumpster diving for a replacement in the future.

$165/pr. on Ebay would be so easy.

 

jb

[Lewis Tanner]

BTW, if they're 'identical', why the bore size difference?

 

You got me, Ford or PBR made the change for reasons of their own. The core of the issue is that there just isn't any way to guarantee that you're getting the 38mm version from the parts store and the majority of the "take offs" floating around the marketplace are likely 40mm because so many more Bullits, Mach 1s, and >98 Cobras were made than the 96-98 Cobra with the 38mm units.

 

 

Jeff, the C4HD's are long gone. They went with my Saleen when I sold it in 2004.

 

The rule may be less open to interpretation if it were revised to specify the actual PBR caliper (with a PBR stock number) and all of the derivitaves that it has. Really, neither the Cobra or the Corvette calipers were made by Ford or Chevrolet.

 

I really don't think anyone has an advantage (or a disadvantage) with regard to brake choices - they're all compromised to an extent and not full on race systems, but the 1LE, 4th Gen Camaro/LS1, 99+ Mustang GT, and the PBR/Cobra in all of its variants all provide about the same level of braking performance from everything I've read, and the rule is there to make sure parity exists between cars, right?

Edited December 9, 2005 by Guest

[Glenn]

technically 3rd gen 1LE stuff cant be used on 4th gens. they are listed separate in section 4.

[bsim]

True, and 'technically,' Baer's shouldn't be allowed either then, since they're aftermarket castings.

 

Anyone running a 4th gen, and who is replacing calipers every 2 weekends (plus resulting pad costs) wants a stronger caliper. Period. The costs are outrageous.

[Lewis Tanner]

Anyone running a 4th gen, and who is replacing calipers every 2 weekends (plus resulting pad costs) wants a stronger caliper. Period. The costs are outrageous.

 

Then start another thread on it or ask Tony to change the rule privately, supporting your assertions with some data, it's got nothing to do with the 38/40mm issue I asked about. All I want is a clarification on the rules as most people don't realize that there is a difference between the calipers and the last thing I want to see is a DQ based on a protest of a technical component of the rules that is obscure at best.

 

And the Baers are cast by PBR as well.

[King Matt1548534716]

Anyone running a 4th gen, and who is replacing calipers every 2 weekends (plus resulting pad costs) wants a stronger caliper. Period. The costs are outrageous.

It is a totally unrelated issue, but that's why the A Sedan brake rules have been changed for 2006 to allow better calipers.

 

Still no comment on my rear caliper question?

[Lewis Tanner]

Still no comment on my rear caliper question?

 

Yeah, take it out of my thread.

 

 

The fact that you can't even ask for a simple yes/no clarification on the rules without it turning into a giant festival of whining and unrelated issues really sucks. Seriously - how this went from a question regarding differences in model year caliper piston sizes that may be affecting some folks without their knowing it to demanding C5 brakes be allowed on a Camaro to the Camaro guys being fed up with their calipers is beyond me. This is exactly the kind of BS that the series doesn't need, IMO.

[bsim]

how this went from a question regarding differences in model year caliper piston sizes that may be affecting some folks

 

Uhhhh, doesn't the C5 vs. C4 caliper question follow the your same line of questioning? The piston size and casting method are different between the LS1 and C5 calipers. Otherwise they bolt up. So, the question of the WHOLE THREAD is clarifying legal calipers, is it not?

[Lewis Tanner]

Uhhhh, doesn't the C5 vs. C4 caliper question follow the your same line of questioning?

 

Not at all - how are you coming to that conclusion? The caliper design itself is also different between the C5 and LS1 calipers and everyone here agrees that there is a performance advantage to them, even you said so yourself. If you want them on your car so badly, pester Tony. This thread has nothing to do with it at all.

 

 

As far as I know, nobody here has bolted a C5 caliper on their Camaro and thought it was legal. I can guarantee there are people running 40mm piston PBR/Cobra brakes that aren't even aware that there's a difference in piston size after 1998. As the 99+ calipers take up more and more of the marketplace, the likelihood of getting a 38mm set from anywhere but a junkyard is getting slimmer and slimmer and there's going to be more and more folks showing up with a car that, technically, is illegal. There's no performance difference between the setups and the only rationalization for asking for the clarification is the fact that the letter of the rules is important and we don't need to ignore that.

 

 

So, the question of the WHOLE THREAD is clarifying legal calipers, is it not?

 

No, in fact it is not. The question of the whole thread is the legality of the twin bore 40mm PBR caliper found on the 99+ up Cobra, Mach 1, and Bullit Mustang. The rules were obviously written with the PBR caliper in mind, and they were most likely written when the 38mm caliper was the only one on the market. If they aren't updated to accommodate the current caliper that is floating around the market and most people don't even know don't meet the letter of the rule, or to specifically exclude them, the possibility for someone to unknowingly run an illegal caliper and get a protest stuck on them is real. That's a very specific issue and one that needs to be addressed - trying to expand the discussion to an all encompassing "I want these calipers" is a cluster.

Edited December 9, 2005 by Guest

[bsim]

So we can start a 'caliper legality' thread, and your question wouldn't fall into it?

 

BTW, the PBR caliper upgrade is popular for the CMC crowd (includes the Baers, 1LE, Fords, etc.). The C4 caliper is the leading cost effective 3rd gen upgrade.

 

BUT, the C4 caliper and the 1LE caliper are different part numbers. SO, aren't those calipers illegal (since they're Corvette part numbers only)?

 

Bottom line, C4 calipers bolt up to 3rd gens, and are legal. C5 calipers bolting up to 4th gens (using that logic) are also legal.

 

To your orignial question, the rules state NO 99+ COBRA calipers. Doesn't that answer your question?

[Lewis Tanner]

BTW, the PBR caliper upgrade is popular for the CMC crowd (includes the Baers, 1LE, Fords, etc.). The C4 caliper is the leading cost effective 3rd gen upgrade.

 

Great, they're the same caliper! Don't you get that yet? The PBR caliper and the C4 caliper are the exact same thing.

 

BUT, the C4 caliper and the 1LE caliper are different part numbers. SO, aren't those calipers illegal (since they're Corvette part numbers only)?

 

If you want to follow the letter of the rules, yes. I'm not sure where you're coming from here.

 

Bottom line, C4 calipers bolt up to 3rd gens, and are legal. C5 calipers bolting up to 4th gens (using that logic) are also legal.

 

How so? The C4 calipers are 38mm PBR calipers, and they are clearly allowed in the rules. There's nothing that says anything about allowing a completely different caliper just because it bolts up. That makes no sense whatsoever and I can't see where you're drawing that conclusion. The C4 calipers are legal because they are a twin piston, non opposing, 38mm caliper - clearly defined by the rules.

 

To your orignial question, the rules state NO 99+ COBRA calipers. Doesn't that answer your question?

 

No they don't. They say the 99+ GT (non cobra) calipers are legal because people wanted to run them and they had a different design. The rule was put out for approval, reviewed, and added to the books. It wasn't intended to exclude 99+ Cobra calipers as far as I know.

 

 

Where can you find the approval of a C5 caliper in this ruleset:

 

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.

 

That's taylor written to describe the PBR twin 38mm piston PBR and the factory 76mm one piston setups. Anyone can see that's what is being described here. Nowhere does it say "any other brake that you can bolt to the car is also legal."

 

Next, we have:

 

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

 

No mention of the C5 calipers here.

 

Then we have:

 

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

 

And I can see how you could interpret this to mean "No Cobra Calipers after 1999" but think you're reaching for that one. This was added to make the 99+ GT calipers legal, not to make the 99+ Cobra calipers illegal. I believe that the 99+ Cobra calipers were assumed to have been legal under the primary 38mm rule above and the rule writers were just not aware of the fact that PBR had superceed their previous design with a larger, 40mm, piston.

 

 

Whatever, though. Argue that the 40mm PBRs are just the same from a rules perspective as the C5 brakes all you want. I don't really care because the logic you're trying to use just doesn't hold water and you clearly can't see that. I'm not getting anywhere trying to make my point here and it doesn't matter anyway.

 

All I want is the clarification of the one single technical component of the ruleset.

 

You can try to get C5 or any other caliper you can dig up that will bolt to your spindle made legal all you want - I really don't care as long as you're playing within the rules and that's what I'm trying to ensure can happen here.

[Adam Ginsberg]

The C4 calipers are permitted NOT because they bolt up. They are permitted because the 1LE and B4C Camaros came with them from the factory, coupled with a 12" rotor ( thanks for the reminder, RP ).

 

It's a huge reason ( if not the main one ) the entire setup is permitted. It was offered by GM first, clearly leaving the Ford guys out WRT braking technology. Rules in A/S were updated to permit the Ford folks the same option ( we follow many of the A/S rules....obviously, not all of them...with good reason ).

 

Ok....that all said....we will get an answer on the later Cobra/PBR 40mm calipers within the coming days, so please be patient.