ehall

What are the key differences between the Big Red and Big Black brake packages?
What are the performance differences between the 993 rotors and the C2 rotors?
What are the differences between the 928GTS rotors and whatever the standard Big Black rotor is?

This is for an 87 non S.
TIA

Techno Duck

The big red's and blacks are the same caliper essentially. The red's are designed to be used in a leading configuration while the blacks in a trailing configuration like on our cars. The blacks are essentially bolt on, the reds require you to swap the crossover and bleeders (basically flip caliper upside down).

Regarding the rotors, for factory application the 993TT rotor is crossdrilled, the standard S4 rotor was a plain jane rotor face. I believe the rotor hats may have a slight offset difference, but someone else may have to comment on that.

SamGrant951

928 GTS are blanks, 3.6T rotors are drilled. 993TT rotors are drilled / 2 piece and I think you need a different hat to use them...

odurandina

i run the the big blacks instead of the reds on my 968 for that reason....

i have a question: i am thinking of running bigger rotors and calipers in the back....... so with the 928 GT front brakes, what size rotors and what calipers COULD i run in the back that would be bigger ?? currently running my stock 968 brakes back there and i'm wondering what would be a nice upgrade.

ninefiveone

Just change to a 5/33 brake bias valve. There's already more then enough caliper and rotor back there no matter what brake setup you have in front.

If you just want something that looks bigger, that's a different story.

Nurburger

You don't need to change hats to use the 993tt front rotors - I use them with the 928GTS biggies and the 5/33 proportioning valve. This set up provides amazing braking power; admittedly more than will ever need, but I do love looking at them. You do need to use Racer's Edge adapter blocks to fit the BB's.

Van

Aren't the 993 rotors a little larger in diameter, too?

gregeast

Ballpark cost for Big Blacks and the various rotor options?

Nurburger

~$2k

ehall

Of the two configurations, leading and trailing, does one have an advantage due to physics? If so, what and why?

That's a question for anyone who might know, really.

ehall

Nurberger, is your car an 86?

TonyG

I don't know the answer to your question. I would guess zero affect.

But in any case, both setups are run in the same configuration on the 951.

If you have the M030 spindles:

993TT 2 piece cross drilled rotors require a caliper adapater to relocate the caliper or different rotor hats as the offset of the rotor is not correct.

965 1 piece cross drilled rotors have the perfect offset and are a direct bolt on.

928GTS 1 piece rotors are not drilled and are the perfect offset and are a direct bolt on.


If you do not have the M030 spindles, you will need caliper adapters no matter the rotor selection.


I run the M030 front spindles using Big Reds with 965 front 1 piece cross drilled rotors with Pagid Blue pads front/rear, with stock rear brake calipers using a 968 M030 cross drilled rear rotor with no factory bias valve but instead use a Wilwood in-cockpit brake proportioning valve.

Hope this helps.

TonyG

ehall

Thanks. I'm a non-M030. I think LR has a kit for my car.

Techno Duck

This is something i wondered a few years ago, took me a while to find this article again but its a good read.

My initial thought was it was just due to clearance with the steering linkage on some cars, but there is some 'science' behind it. Mostly involving wheel bearing load.

http://www.auto-ware.com/ortiz/Chass...-April2004.htm

TonyG

Correction to my previous post....

I don't think they have to be M030. I think the 88 turbo s and later 951's all used the same caliper mount method. So even if you don't have the M030 option, but have the 88 turbo s or later car, you can just use either the GTS or 965 rotor as a direct bolt on. Either the big blacks or big reds will also be a direct bolt on although you'll have to swap the brake fluid line to the other side of the caliper for the big reds.

TonyG