AltitudeRacing

Howdy folks, currently working on my 75 911 project, and looking for some help.
I am wanting to upgrade the original 911s calipers and rotors to something with a much larger diameter for racing and heat dissipation, however I am at a crossroads.
The only option I keep finding require drilled rotors which I do not want to run.
Does anyone know of any combination that uses plain or even slotted rotors? The 930 swap does not offer any options, the 991 big red swap doesnt either, and neither does the ERX caliper kit.
Kind of stuck here., any help appreciated.

I also searched as much as I could, but any pertinent thread was dead or left in the air.
I am also not opposed to any extra work, IE: Changing the hubs out or getting some custom work done etc. Just don't have any direction here.
Only rotors I found that are plain/slotted were the ones for the factory 911s brakes which are incredibly tiny.

Speedster911

The common upgrade for a 75 is to go with Boxster calipers ( need to be non S calipers) which also require the later larger discs assuming you are running 15" rims. 930 not providing options, not sure what you are referencing, an early 930 caliper provides amazing performance.

Need to know what size rims you are running to provide a definitive answer

AltitudeRacing

I am running 17” wheels as its a track car mostly. I looked at boxster brakes but not worth the cost for that small of a heat sink. The 930 brakes were my original choice but the only rotors that exist are the vented (cast drilled) rotors and I am looking for plain or slotted rotors, but it seems that doesnt exist. I am trying to exceed 300mm rotor diameter as I have plenty of room with the 17” wheel.

Mark Salvetti

There is a recent Wheeler Dealers episode where they upgrade the front brakes on an SC to 6-piston calipers and slotted discs. A UK supplier, but it wasn't clear where to get them. I would think they might have also needed a new master cylinder, but they didn't get into that.

I think the system may have come from Carbon 12 Racing, which seems to just be on Instagram. These guys look like the same parts: https://www.stuttgart-classica.co.uk.../big-brake-kit

Mark

AltitudeRacing

Thanks, I will look into that, this car is a dual master cyl patrick motorsports kit and therefore MC sizes dont matter as I can just swap them out and adjust bias accordingly.
I just want a large disc and some stateside availability to have some stock on hand. I saw Coleman seems well priced to make rotors to my spec. May have to do floating fronts and get the rings made by Coleman.

Bill Verburg

what rotors to use will depend on what calipers are chosen

just a reminder for some, for track, use it's the rotors that are important, correlated to weight and speed, further modified by track specicfics.

for the typical track 911/930 chassis 930 sizes are right around where you want to be ie 304x32 frt and 309x28 rear., these provide adequate thermal capacity for all but the most extreme stripped out track cars.

the biggest i've seen on the typical 911 track car are 993RS size 322x32 and 322x28, these are overkill for 99.999% of all 911 track cars

looking no drilled is also a great ide, drilled will crack and wear much more quickly than slotted.

slotted front in ~304x32 should be readily available in a 2 piece version from Wildwood or Coleman, I haven't looked at Brembos catalog lately but they may also have something. You would need to supply the flat hats to bolt to the 911 hubs though. These can be made by a local shop or purchased from various suppliers(Porsche oe as a last resort), Coleman would be hig on that list

in back there are no off the shelf hats(assuming going w/ a two piece rear setup) available for an appropriately sized rotor disk and you lose the parking brake(these may or may not be important to you, on my track cars I liked the parking brake for trailering, not necessary but still useful)

here's a set of custom Coleman rear hats that a fellow named Scott( Winders (screen name Winders on Pelican) had made by Coleman for the back of his race car w/ 930 calipers


don't know if they are generally available or not

AltitudeRacing

Thank you very much for the insight, my research has led me to a similar solution with the front brakes, getting a floating rotor and using someone like coleman to provide me with flat face or slotted rotors over drilled. I would most likey just run the 993 turbo brakes however the piston diameter is a bit small but I am assuming that would work fine with the matched rear caliper and matched master cylinders. I am however at a crossroads with the rear rotor and caliper as I cannot find anyone making anything to attach the rear 993 turbo caliper, only the front. I wish the 993rs caliper were better priced. The other option I looked at was the elephant erx kit which would allow me to run the standard pad design giving me lots of options. The rotor diameter seems fine but I am back to square one with finding non-drilled rotors. I would have to run the early 930 floating front with a custom rotor ring from coleman or someone and then the rear I would need to fab up a something like the picture you posted but I agree I would like to have an e brake as I do use it for parking the car and moving it around when not in use. There are times where I cant use chocks.

Bill Verburg

993tt/RS front are easy on a 911, use stock rotors, unbolt the hat, bolt on a flat hat and caliper adaptor
These are 993RS/tt fronts on my '75 C3





On my track oriented 993 I use Girodisk hat & annulus, but a flat floating hat instead of a 993 raised hat would be easy to do



In back the issue is that per conventional wisdom to retain the p/b the annulus need to be ~330mm minimum, but A buddy just got some floating slotted 322s for his 993 rear so it can be done

You would need to have 911 p/b compatible hats made as the 993 versions won't work

again on my '76 I have some custom 2 piece rear rotors, 322x28 993RS/tt is the basis, then the center section is machined out and a 911 p/b section is pinned in

wildcat077

Seems you already have the Fabcar dual master … i went with 996 TT brakes on my 89 and i’m using Sebro slotted rotors along with a Fabcar dual master and Tilton bias adjuster. I changed the master and removed the stock proportioning valve.
I had lots of fun in the black run group with PCA running down GT3’s under braking , the look on the guy’s faces was priceless !
Bill is the go to resource for brake advice, although i find the stock brakes are plenty good, i just got a smoking deal on the 996TT package so i decided
to go for it !

Cheers
Phil

raspritz

To the OP: You use the words 'track car' and 'racing'. Big difference. If the former, feel free to go nuts. If the latter, make sure whatever you do is 'legal' for your intended race group.

wildcat077

Raspritz has a valid point …
If you plan on racing , PCA is pretty **** when it comes to eligibilty and a major brake upgrade is no bueno !
Should you want to have some fun with DE’s then anything goes.I had fun with PCA DE’s for 7-8 years before i decided to buy
a dedicated SP2 race car.Any performance upgrade is an expensive adventure and in my opinion the stock 911 brakes offer plenty of stopping power with the right brake pad combination and proper cooling improvements.
Although i’m not the one to offer a good example as i put 996TT brakes and stuffed a 95 3.6 in my car … oh well

Cheers
Phil