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Some here are practical, often careful, and very professional in their engineering. To me, that's admirable, and especially so for those that then sell and work on these great cars.
I thnk other people want to design and buid things for the challenge, even ignoring sensible economics. I also think that is damn cool.
Definately not for everyone, but neither are 928s.
I thnk other people want to design and buid things for the challenge, even ignoring sensible economics. I also think that is damn cool.
As long as the next owner doesn't bring it to me to fix when all that stuff goes sideways.
I, literally, just got done with such an odyssey; I got to develop the beta version of something that was installed on a 928 in 'alpha mode' for the previous owner that went sideways in 4 different dimensions for the current owner.
Fine initial concept, but missing one product manager and one technical writer, and shy two or three engineering and testing iterations from being an actual product.
I would rather see this level of R&D work go into a "X38 Plus" bolt on front fender. An artistic and aesthetic challenge that was never quite met by decades of many aftermarket attempts. This fender would have no mods to the bottom sections (Like the original x38) but end up with more flare/ coverage for a wide wheel size. (not too wide, of course) My artistic design criteria for a final product would be for it to look something like "what is different about this 928? I see a difference in the fender but I can't identify exactly how it's done" Much like an x38 fender..almost like what a standard GTS front fender SHOULD have been.
That said, This is Jerry's hub thread, its his time and resources so I hope he sees his concept to whatever end becomes of it.
Fine initial concept, but missing one product manager and one technical writer, and shy two or three engineering and testing iterations from being an actual product.
......Like 98% of most aftermarket things. (And a percentage of factory stuff.)
That whole "testing" and be ready to toss the entire idea into the trash can (if it doesn't work as intended) escapes most people.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
Cheaper? I dont think so by a factor of 4. Have you priced a set of custom wheels lately?
I sure have. It’s not just about hard costs, it’s about all the hours put into R&D, prototypes, testing etc. A set of wheels from Augment run about 4K cdn. At say $50 per hour (which is low) that’s only 80 hours.
Not trying to take away from the OP’s idea. Just shinning a light on the real cost.
——
Jerry, best of luck and I hope it works out for you.
Reality: I'm all in for a hub and hat solution that gives brings the wheel face back 10mm or so, but leaves the caliper and brake disk in the original position relative to the spindle. With that, you'd need to shop wheels carefully for enough wheel-to-caliper clearance, and figure out a center cap solution to work with the hub nose sticking out that extra 10mm.
Porsche wheels with 55mm offset are pretty common, so the 10mm change makes a total 65mm effective offset look pretty good. That said, even 5mm would be a help, and get the numbers the same as the factory 8" clubsport fronts, But once I'm shopping for hats and knowing the center caps won't fit even with just 5mm adjustment, the only difference would be the wheel-to-caliper clearance concerns.
For a one wheel set fitment, I'm more inclined to get a set of those 17" Augment Clubsport-look wheels in 8 or 8.5" width for front and 9 to 9.5" width rears, with the correct offsets. But that's me, and my interest in keeping the car closer to original. If I could fit Mich Pilots in 16" sizes I'd have the original wheels on the car. I move to the 17" wheels when 16" tire availability became an issue. I hesitated a bit on the C4 option wheels I have as I though they looked too flashy. I 've gotten used to them, but that's all.
I got a call from the machine shop. My parts were ready. I was extremely pleased with the quality of the machine work. I got them back to my garage and the further development begins.
There are a few options with this solution. All leave caliper and rotor in OE location.
1. Modified 928 Spindle + 944 hub + 5mm spacer + Cayenne 350mm rotor = yields 11mm of 'negative spacing' (Can use use GTS caliper with small mounting pad spacer)
2. Modified 928 spindle + 944 hub + custom alu hat rotor = yields 16mm of "negative spacing" (with Audi D2 S8 caliper I can get a 360MM rotor, that's more than 14".
3. Modified 928 spindle + 944 billet hub + custom alu hat rotor = yields 16mm of "negative spacing" (with Audi D2 S8 caliper I can get a 360MM rotor, that's more than 14".
Option 1 is low cost and the yieid is sufficient to allow the use of just about any common and available Porsche wheel
the other 2 options are a bit more dear but still amount to about 1/2 what a custom set of wheels cost.
Modified 928 spindle
Modified 928 spindle with late 944 hub
Modified 928 spindle with late 944 hub shown with bearing sitting flush. Jerry will know why this is great.
Must use 5mm spacer when using Cayenne 350mm rotor
Last edited by icsamerica; 12-26-2020 at 10:06 PM.
The use of the Audi D2 S8 caliper will allow the use of a 14.2" inch rotor. Weird... The S8 caliper bolted right up using the OE bolts. There are many many 928'ish things on a D2 Audi A8, way to many for it to be an co-incidence.
Last edited by icsamerica; 12-23-2020 at 11:15 PM.
WOW! Talk about taking the ball and running with it . . . . If this isn't a touch down, it is certainly close. Or maybe it is only waiting for the extra point. That would be to put it on the car and see how it all mounts up. Nice going ICS, Thanks for following through with my idea.
For grins, drop that into a wheel and verify that there's sufficient clearance between the caliper and the inside of the wheel. The other possible interference is at the lower ball joint; I don't remember if the ball joint is bigger than the spindle arm it lives in there.
For grins, drop that into a wheel and verify that there's sufficient clearance between the caliper and the inside of the wheel. The other possible interference is at the lower ball joint; I don't remember if the ball joint is bigger than the spindle arm it lives in there.
Awesome work!
This is Very workable in many wheel scenarios where larger wheels are upgraded brakes are the goal. So far I've tested 2 wheels with the setup that yeilds 11mm of 'negative spacing'. Panamera Front 18x8 ET 59 and Rear 18x9 ET53
So far I have only been able to test the ten spoke Panamera 18 inch wheels. It all clears by a mile. Shown below is a Panamera rear wheel that is 18x9 Et 53 on the front of the altered spindle. The negative spacer setup yields 11mm in this scenario for an effective ET of 64mm just a measly 1mm from ideal. Theoretically speaking a higher aspect tire, which I recommend when using an 18 wheel, would alter the geometry in such away that the intersection point is farther away from the axle center line so the resultant scrub point would end up being exactly 65mm or slightly more.
Shown below is the upgraded setup. S8 calipers which are very similar to the GTS calipers, Cayanne 350 / 330 rotors and a 18 x 9 inch wheel. This setup with a proper tire would have greatly increased capabilities all with the correct suspension geometry. In this scenario there is no possibility of ball joint or tierod issues becasue the rotor face is in the OE location and the tie rod joint is well inside of a 18 in wheel. This would help bring the 928's performance in into the modern era with fewer compromises because what really separates good modern cars from good older cars is wheels, tires and brakes.
Furthermore the custom rotor can be larger, 14 inches or more and moving the caliper outward to accommodate the larger diameter rotor would increase wheel to caliper clearance. Much of this could be attractive to a 928 owner who would want to increase the limits of a 928 with fewer, if any, compromises. Perhaps the greatest performance increase would come from the lowering that the correct or higher ET allows. That's what I'm after too becasue right now I'm clearance limited for lowering.
I can imagine the S4 calipers will clear but be super close using Cayanne 330mm rotors. I will test this at some point later today hopefully this opens up another workable solution.
Last edited by icsamerica; 12-26-2020 at 04:09 PM.
12-19-2020, 04:21 AM
