mark kibort

cool! that matches the spec. imagine that!

adapters being machined tomorrow to the new spec.

thanks for noticing the 7.5mm vs 6mm thickness. we would have been off by 1.5mm if you hadnt caught that! who would have thought that there would have been a difference there! ???

yes, they are huge, NOW I WANT some reall 13mm rotors! mine are only 322mm vs these which are a true 13", or 330mm! maybe the S4 calipers can be moved inward by 9mm? and pushed bigger diameter by 8mm. because its an radial mount, that might be tougher. certainly doable. from scratch, a spacer is made 17mm thick from bar stock (not just a fat spacer washer like the original mod) , and , then with no gap, drill and tap 2 holes inward. Oh, that only gives 12mm inward and no side wall from hole to hole, and no room for the bolt head, even cap bolts. maybe the adapter plate could rotate the caliper down or up to get away from this problem,but now the distances will be complicated to keep the calipers parallel to the rotor surface. sounds like another thread!
mk

xschop

Yeah sounds like an axial mounted Wilwood to Cayenne rotor thread, what I smell.

mark kibort

hmm, maybe not worth that much work for only 4mm outward movment (radius not diameter) correction to above mention of 8mm outward push out.

928mac

Mark I don't know if this will help but I found this link for you to take a look at.

Good luck with your build

http://www.jackals-forge.com/lotus/9...keupgrades.htm

mark kibort

we are still getting the raw material. I think i asked before, but i want to be sure. what should it be made from? 6061? or steel?

xschop

start with 1.25" 6061 and add 0.25" to both thickness dimensions

mark kibort

should I just make this out of steel?
what is our bumper aluminum made of? I wonder if there is a thick part of that I can use.

mark kibort

Thanks. thats more appropriate for the S4 to GTS rotor size conversion and caliper radial spacer project. it just shows that the S4 and GTS rotors have the same offset .

xschop

Hey Mark, thought I would post this. I took the New Cayenne rotor to the shop for the 944 spindle/hub mockup and put it on a surface plate (0.0001" accurate) and got these dimensions. The 68.6mm dim. I quoted was using a formica table top in my garage.... you can take these dims to the bank....

mark kibort

I like the formica dimension. the shop dim is off alittle because it is adding the two distances, and the hub hight is tough to measure because it might not be flush with the rotor surface where it ends, unless it is rotor surface to outside of the hub surface. the fact that the rotors are 7.6mm vs the porsche 5.8mm, is the 1.6mm diff, and im glad we were able to take that into account, plus we were using 69mm for the rotor thickness total, and its really 68.5. that means that critical adapter dimension is really going to be 13.1mm not the original 15.15mm.

xschop

that 37.25mm dim is exact from outer flange/wheel interface to the inner rotor sweep surface (indention step not counted)

That 7.6mm dim is on the money at all points aroind the radius of the 85mm hubcenter.

I'm going to set these two up on the CNC and machine the setscrews for the 944/968/928 hubs because I'm going to sell these off when I'm done with the brake mock-ups. I'm going to churn centering rings out that are 7mm thick later on.

mark kibort

so, you measured 68.5, yet you are a half mm off at an actual 69.3mm? oh god, why cant these things just follow the drawings which were 68.5!
I trust the 7.6mm, as thats what I got too with my micrometer.


why are you churning out center rings again?? to center the rotor to the hub? how is it going to stay in place?

xschop

Hey the mic don't lie.
Ok. once again the 944/968/early 928 hubs are 155mm O.D.
Cayenne rotor is 157mm Inner hub I.D. Interface. I set the Cayenne rotor up on a 944 spindle/hub and the 928 hub tonight, Unless centering rings are used the hub will set 1mm off center due to its weight before being bolted down.... The Bracket mock-up for both spindles will not allow for any oscillation...

Here's a comaparo of the wimpy 951 rotor to Cayenne rotor.....



944 late NA spindle/hub with Wilwood 4 pots and Cayenne rotor.....

pcar928fan

So you might say the rotor is hub-centric huh? Wow, weird...who would have thought.

SharkSkin

I thought the hub centered on the I.D. of the hat, not the I.D. of the hole in the outer flange that you're looking at in the last two pics.