bandsmalter

Thanks for your comments and information Bill. Much appreciated.

Sam-Son

A barrage of information as always. Appreciate the level of detail you provide. What I'm fuzzy on is how do the various kits impact that brake stress index number? Would you just assume the 86 930 number carries over to the US Carreras if outfitted with the 930 brakes? I'd imagine the vehicle's weight plays a considerable factor.

Based on what you've said re: BSI number a stock US 3.2 Carrera wouldn't have adequate brakes for track use in stock form.

I think what I like many are looking for is "for application X you should select Y"

Spyerx

Good info. the 930 was always the factory hot setup, but ratty sets are what, 10k now?
The elephant kit is nice.
Master/rotors/calipers, fit under 15" fuchs, work with factory mounting

Bill Verburg

BSI melds, brake thermal capacity which is a function of rotor size, chassis mass and speed potential.

the bigger the rotors the lower BSI, the more chassis mass the higher the BSI, the more speed potential the higher the BSI

For a BBK to be worthwhile you want bigger rotors better bias and a better pedal feel, but the rotors can't be too big or they won't fit in the wheel space and there is a cost in unsprung rotating mass

for a 3.2 Carrera 930 brakes are about all you need, 304x32 front and 309x28 rear, these fit in 15" wheels 8 or 9, and w/ a bit of extra bother 7s

Finding rotors that fit can be challenging

911 rotors fit and 930 rotors fit but no other Porsche 1 piece rotor fits.,
in increasing order of thermal capacity
911 fronts are 282x20 or wider 292x24 or 930 304x32
911 rear are 290x20 or wider 290x24 or 930 309x28

front 2 piece can be found, you just need an easy to make flat hat so you could get various sized rotors to fit, apparently that's what Willwood offers

rear is another kettle of fish as you need ~330mm for a 2 piece that retains the parking brake, these won't fit 16'

so in back you use stock 911, or wide 911 or 930
and of course you need calipers that fit the rotors stock 911A fit 282x20, wide 911 A fit 282x24 930 or 964 or 993 fit 930 304x32

similarly in back

next you want bias optimized the old 911 1.491 is pretty close to ideal more front wastes brake resources more rear can get dangerous I use 1.426 in both of mine but the cars are specially setup for it, for fixed bias i wouldn't go any lower

930s are 1.579

You don't really need more brake torque unless you go to stickier tires, as the weakest link for brake torque is almost always the tires
and lastly pedal feel
you want a pedal ratio ratio( composed of hydraulic and mechanical specs) that gives a nice high hard pedal feel. the hydraulic ratio needs to be in the range 38 to 25 the lower the better to a point, the lower # gives a better feel at the cost of more leg effort, 32 is the low end that Porsche uses for street cars.

Schraders

I have owned a specialty vehicle shop for the last 22 years, we focus primarily on domestic cars but have done our share of imports including early and late 911's. We install about 40 Wilwood kits a year, again mostly domestic. I've never had a comeback, ever. Not once. Their kits are well engineered and transform the braking performance of the vehicle. Of course, pedal ratio and master cylinder bore must also be correct, and the rest of the steering and suspension must also be up to the task. There's a ton of specs on the site, and virtually anything else you need to know is only a phone call away. They will actually pick up the phone and answer all your questions, I can't say the same about Brembo, AP or Baer. I've never installed the 911 kit, nut I have no reason to believe it won't work very well.