xschop

I finished mocking up this same caliper/rotor upgrade to the 944. Now I'm working on the early 928 Hub/Spindle..... Same wheel clearance as the 944 mock-up....

Landseer

Thanks for making these brake conversion posts.
I'm learning a lot from them.
There is a lot of confusion out there on this subject across models.

xschop

The Cayenne rotor is 157mm hub centered and the Early 928 hub is 155mm O.D. So centering rings are needed or the rotor will be 1mm off radius at bolt-up.....

genikz

I'm very much looking forward to your results!

mark kibort

did you make batch of them?

xschop

Not yet because the centering rings transfer between the 944 and 928 hubs for the mock-up. Heck I may set up a 911 hub/spindle later. I haven't been able to go any where the last two days. There is a 3 1/2 ft snow drift blocking the shop door. The Wilwood caliper will rotate down and still clear the steering knuckle, but If I design it out of 1/2" steel, I may be able to make it isometric and right between the spindle ears.

xschop

I am back on this project and am redesigning the adapter bracket to bolt to the inside of the 928 spindle just like the factory caliper did and make installation easier with a 7/8" thick t6061 billet adapter (the 1st prototype was steel and bolted to the other side and PITA to install). This presented a small problem where I rotated the caliper down and the body of the caliper comes close to the steering knuckle and I don't have one on hand to measure.... Can anyone give a close measurement fom steering knuckle base/center tie-rod outer edge?

xschop

Anyone have the dim handy? If not looks like I have an excuse to hit the bone-yard later.

xschop

Alright it clears! Sucks going to the boneyard in 104*

One interesting side note is the outter tie-rod knuckle IS NOT METRIC, just like the 944 knuckles they are 1" TPF

Speedtoys

How much swept area is unused under that WW caliper??

I dont like the idea of going big, if I gotta throw away so much swept area.

xschop

About 0.375" with factory Wilwood Superlite pads. A deeper pad can be made if you are so inclined. The small unswept area is worth the $450 in savings from having to build Custom hats and rotors. The Cayenne rotors in the Pic are slotted and $130/pr shipped. The GT3 guys are using them on the track. Also tonight I discovered that this Caliper can take a shorter Radii bracket and fit 322GTS rotors and possibly even 304mm rotors(may take a very slight trim on the spindle lower caliper mount boss). As you know the 928GTS rotors are expensive, the whole reason I'm doing this. I will have the new prototype done tomorrow and can program the other mirror image side during machining.

Speedtoys

*nods*

I think ive sold the deeper pads before as a 'bremtek' cut...been a looong time.

Maybe im silly, but I'd hate losing 'PORSCHE' calipers...

xschop

There are no "PORSCHE" caliper that fit these spindles (104mm ears), and if there were, what would be the cost of a new "PORSCHE" swap?

All New Wilwood Calipers, Pads, Cayenne Rotors and adapters will cost $700. And the Wilwoods have 3 different piston size choices as well. Plus I have tested this setup on my 2900LB 948 and there is NO FADE to these monstrous rotors

Speedtoys

Oh no..not denying how well it'll work..not at all. Sorry if it seemed that way.

xschop

I was never offended and value anyone's input (well most sane folks anyways). If I were to race a 928, I would want these spindles and hubs, they are the beefiest of them all at the stub shaft. The problem with them is they had cheesy brakes and the 104mm spreadwidth on the caliper ears made them a nuissance to a BBK. I'm hoping these fit under a 16" phony...17's no problem.