924S Big Black's Rotor Question

[JivenJim]

Hey guys,

Down for the winter season and have been upgrading to a set up 968 Brake systems. I got the complete suspension from a junked 968. (RIP)
So the Front is in place with modified Strut cuts and slotted shim. 968 Front Spindle align and look Great.
The Question is what am I suppose to do on the Rear?
The 924S has a smaller rotor offset (hat size) So it looks like it should be the depth of the Front Rotors but needs the hollow inside for Ebrake and rear hub. The rear brakes bolt on fine to Stock Trailing arms, but I need the Correct rear rotor. Annoying since I have Brand new 968 Cross drilled Zims rears.

I was then thinking that I would just drop on the 968 Trailing Arms that I got and then I'm home free. Wrong.. That moves the wheels outward about 1-2 inches and there ain't no room under these tiny wells for the 245's X 16 I have crammed in there. Hoping to avoid Fender flares for now.

Any Ideas or know what the correct Rear Rotors should be for 924S with Stock Trailing arms and Big Black 968 Brakes??.

This Car is going to get a lot of track time this year and with the say 275 NA HP I’m pushing, I really need to avoid fading in to the back of a Honda or something.

Thanks

[Techno Duck]

I think you should be able to use early offset rear rotors from the '86 944 Turbo. The 924S is sort of an oddball collection of parts having early offset suspension with late offset wheels and the early trailing arms.

The 968 rear caliper and all of the 944 Turbo calipers are the same size, mounting points, brake pad...etc.

[JivenJim]

Thanks Techno,

I was thinking something like the early Turbo's and then realized they didnt' make the Turbo till 86' (post 85.5 change overs) then I heard that the 86 was the Oddball collection for that family. I'll hunt the vendors along that line.

Happy New Year 2008!

[nynor]

how did you get 275HP out of a NA motor?

[Techno Duck]

Originally Posted by nynor

how did you get 275HP out of a NA motor?

968 3.0L engine

[jcommin]

My curiosity is up. Did the 3.0L 968 crank out 275hp from the factory? If not, what was done to get it to produce that much hp?

[nynor]

gotcha. very nice!

[JivenJim]

I really don't know 275 yet. That's projected to the Crank. There's another post in the coming. First I have to get it road tested. But lets just say it was alot of work and not a max life type of setup. I now keep a spare 968 Engine Handy.
I do know some racer that have done over 325 Hp with it but that's gotta be about max without a blower.

Here's some pretty pictures 924S with 968 spindles, 968 Rotors, 968 Brakes, Modified Stock Strut housing and Ride height kit JB putty welded. Shim note on left side of spindle kept bottom strut spindle hole and removed additional slot up a 1/8" or so to match Spindle. Since the Shim is slotted it allows the Camber bolt to be dialed in as normal. Stocks hubs look kinda pretty after hitting them with a wire brush on my drill.

I confirmed that Techno Duck man's 86 Turbo Rear Rotors should have the Correct Hat size for my early 924S trailing arms. Kinda confusing since I use late ABS offset wheels on the 924S. Those should be in early next week, then I'm off & Rolling. Early Feb it's off to NASA in Big Willow Springs for my HPDE training.

[Tam Lin]

Originally Posted by JivenJim

I confirmed that Techno Duck man's 86 Turbo Rear Rotors should have the Correct Hat size for my early 924S trailing arms.

Yep. Seconded.

OT: That's one of the real pains of the 924S, especially when doing suspension work: Getting the correct (alumin(i)um) front a-arms took me about 3 goes, as people kept sending me the late offset ones. Now I order all parts pretending it's an early 1986 944 turbo. So far, so good.

Other 924s peculiarities are fuel lines on the left (instead of right) underneath car & subsequently a different fuel rail, and a weird fuel filter location.

[JonA]

The 924s clutch hydraulic lines are unique too, not what they will try to sell you. Try 951 423 189 01 for the hose. It's borrowed from an 86 turbo 944 or something. Just learned that one the hard way.

Jon