vt951

Ah, ok. Now it's starting to make sense. Let me find out what I want then, and get back to you all. Sorry for the confusion.

SamGrant951

Big blacks/reds will clear your 17's but not 16's. Thee 928s4/turbo s setup will work with 16's as well.

95ONE - you may be correct but I know lindsey sells the rotor hats for both early and late offset and they carry different part numbers so I think they are needed.

odurandina

in that case, you will need 928 GTS rotors to facilitate longer rotor "life span" that solid/slotted rotors offer. Pelican parts has them, from Zimmerman solid/non-slotted, but they cost a penny...

the stock slotted, 928GTS rotors are available at Sunset Porsche [west coast], Suncoast Porsche [east coast].

This rotor will work fine with either big red or big black calipers.

as I was mentioning earlier... the 928 S4 rotors are very good but not as large as the big blacks.

You need the bias valve or you won't get any power to your rear brakes.

Bri Bro

You and Sam are correct, I keep calling the GTS the S4. The GTS was the last run of the 928 and had brakes upgraded due to the increase in HP.

All the Big red/black rotors are 322mm and they will fit under a 17 inch rim but you need a different adapters for the 86 offset. Look at the link below and it shows all the different rotors and adapters you will need.
http://www.lindseyracing.com/LR/Parts/944BRAKECOMP.html
In one piece rotors you have the:
911 C2 3.6 turbo
928 GTS rotor
In two piece (need to purchase a hat)
993tt rotors
If you still have the 86 offset hubs, I would strongly recommend you swap to the 87-88 offset hubs. For the upgrade you are doing, I would go to the big blacks vs the 951S to get the bigger rotor which will reduce heat fade and extend pad life. The rotor diameter on the S4 / 951S is 304mm

Joe Toth

I have a set of calipers front and rear from an 88 Turbo S if you are interested. If you buy the calipers you can have the rotors free (only extra shipping cost for 68lbs of rotor). The front rotors are so good I didn't have to back off the pads to remove the calipers, the rears have a slight ridge.

vt951

I need to go with the big blacks or big reds, not turbo S calipers. I'm not only doing this for heat capacity/dissipation, but also for the larger piston diameters, which will help brake pedal effort when I get rid of the brake booster. (Going manual brakes to make room for the LS1.)

odurandina

VT,

Make no mistake on this point, You ABSOLUTELY need to keep your power brakes.

You can fabricate a hydrolic-assist via your ps...

Then, you'll have the braking force you need thanks to the big brake upgrade you're already doing...

here's just one example... doing yours will be easier.


http://www.off-road.com/trucks4x4/ar....jsp?id=264070

./

vt951

odurandina,

I appreciate your concern, but I have done some research on hydroboost and also talked with guys that have done manual brakes on these cars. Manual brakes supposedly work very well if you go with the big reds/blacks and 5/33 proportioning valve. You can also move the brake pedal linkage up a little bit to give more leverage. I am going to start with that and see how it feels. If I don't like it, I will either add hydroboost or go to a dual master cylinder setup.

Bri Bro

Your 86 does have the smaller sized caliber pistons. The big blacks are the way to go but I think the piston diameter of the S4/951S is the same as big blacks, 36 and 44 mm. The main difference between the 951S and the Big Blacks is the size of the 322mm rotor.

The 1986 944T have 36/38mm pistons, later 944T cars have 36/40mm pistons. The 951S have Big Red sized pistons in a 993 frame with 36/44mm pistons with a 304mm rotor.

vt951

Brian,

Thanks for your help. Are you saying that the 951S calipers are the same as Big Blacks, or just that the piston sizes are the same? I think what you're saying is the latter, and that the caliper frames are different so that they fit around larger rotors. But, in any case, I will get the same brake clamping force regardless of whether I go with 951S or Big Blacks/Reds. The difference would be the heat dissipation and lower wear rate of the Big Blacks/Reds. Is this right?

Alan

Aspkiller

I have a couple of sets of Brand New Original Porsche "Big Black" calipers, with bolts and Original Porsche solid rotors and dampers. One of the sets is here in Phoenix, somewhere in a pile of new parts purchased as back-up parts for my 91 GT track car and another car I'm building. I'm keeping them. The others are at my house in Lake Tahoe, but can be sent out within a week or so. The full set-calipers, bolts, rotors, and dampers are $1,305, plus shipping. If interested, E-MAIL me at aspkiller@***.net. Don't PM.

The dampers are Original Porsche and are 44mm and 36mm.
The rotors are 322mm.

95ONE

I missed what year his car was? I see references to an '86, but I can't find where he actually says itImportant since that may limit rotor options. And In one of his posts, it seems he thought the $218 quote was for new calipers. Which was, of course, for used.

vt951

95ONE... I assume you mean me? My car is an '86. I'm buying a set of 968 hubs and spindles as well, mainly for safety reasons (heavier duty spindles), but also so the GTS rotors will fit over the hubs.

Btw, you can actually use '86 hubs if you turn them down slightly. You just slip the rotors over the outside of the hubs, and they are sandwiched between the wheel and hub like late cars. I think you lose about 3/16" of lug length, but for most wheels that's probably not a problem.

95ONE

Yes sir. ok, so you're aware of the needs of different rptor/spindle combo. Interesting though,I hope you aren't speaking of Matts 968 hubs/spindles he just posted! I scooped those up & paid as soon as posted! lol.

333pg333

944 TURBO S = 'Medium Blacks' aka S4 calipers. '86 951 = 'Small Blacks'.
GTS = 'Big Blacks'.