VT928

Mark,

When you try to make an adaptor thatwill mount to the "S" spindle your run into a problem with mounting the S4 caliper. It is because the one of the adaptor mounting bolts is blocks the S4 caliper bolt as it comes downward to sdrew into the adaptor. The two differring mounting stratagies the "S" from the side and the S4 from the top is the issue.

I would think now that Brembo is doing more 4 and 6 pot calipers that mount from the side it might be possible to use the "S" spindle with and adaptor and a side mount 4 or 6 pot caliper.


Paul

Aspkiller

Mark-
You've gone about it all wrong. Given the time you've spent noodling and writing about this project, you could have gone down to your local mini-mart and gotten a job that pays $7-8 bucks an hour. You would have made enough $$ by now to buy several sets of calipers, rotors, pads, bolts, shims, spindles, etc. and still had enough left over to have paid someone else to install them.

May the brake gods be with you.

xschop

No, he didn't waste time, just found a way to get bigger brakes/better stopping power using off-the-shelf and inexpensive parts. Along the way enabling others to decipher other upgrades. If anyone was to build a big brake kit with various parts, this thread has all the info needed. I will be referring back to it for future reference. Much in-depth knowledge here.

mark kibort

Its not for me, its for the 928 community of "S" brake wearers. (mainly for Scot, and I like little challenging projects like this)

Plus, i would rather design quick fix, cheapo brake adapters than work at a minimart.

mark kibort

so, the different spindles keep this from happening? doesnt have anything to do with the ball joint clearance?
anyway, is this clearance problem of the downward bolts, interfering with the side mount bolts, can that be solved by using a larger diameter rotor? say the 330mm? or is it just in the way period?
anyway, I thought for sure there was an adapter kit that just allowed you to bolt up S4 calipers. guess not?

Now, I hope this adapter works. Looks like it will and scot will have some massive rotors for his older 928!

xschop

A larger Dia. rotor and larger offset would allow the radial bolts to have more material between them and the axial spindle ear bolts. Due again to this thread knowledge, this is the reason why there is a big brake kit requiring use of the 76mm eared spindles. 104mm axial spindles interfere with the 130mm adapter radial bolts. No one has taken the time to rotate an S4 caliper down and build an adapter for them to mount to 104mm spindles.

Aspkiller

It's really interesting how some take what should be an obvious tongue-in-cheek post way too seriously. Laugh it off, it's good for the life line.

svp928

xschop- Devek did already make an adapter for S4-to-S, and I have it on my car- an 85 with F40 calipers (same size/mount as S4). There is a thread about the conversion in the archives somewhere. I think its called "85 big brake conversion"...

Devek is not in business anymore, but he still owns the design I have here, and I won't make his parts for someone else. Doesn't mean you can't design and make your own, though, its really very simple. His design does require a hat specifically made for that offset, and a rotor that is more $ than most will spend.
So, its been done, but its not the inexpensive way that is the subject of this thread, so I will not hijack anymore....

xschop

The 330mm rotor and 69mm offset opens up the gates on adapter design. What size rotor did that/your kit use? I am only building a Wilwood kit for someone else ATM. Later, I may do something else. according to the 944 guys, the axial calipers that are in this thread are all cast with the same dimensions but with different size pistons. This also creates more options with smaller Dia. Porsche rotors (298,304). I can get an 87-up 298 x 28 rotor fitted to these spindles/hubs with these brembo calps.

MK, I never saw a reply...How much more clearance does the back of the 69mm offset Cayenne rotor have to the B-joint?

mark kibort

I havent been back to take those measurements yet. PLUS, if you remember, this cayanne rotor is way way under spec. its 23.5mm thickness if you can believe that! some say, it should be 32mm stock, and never turned if under 30mm. somehow, this gal friend of mine had these rotors on her Tourareg. I would swear they started out at 28mm, but they are directional, so not rear rotors. I think the tourareg guys are right. these things were turned a couple of times and just wore out. the lip is 27.5mm as it stands now. anyway, the measurement to the ball joint will be off 5mm or so due to this worn part.

Now, Scot has to step up and buy a set of these rotors to make this thing happen, but we might just mount up the old rotors and drive it around to see if it works using some old pads.

xschop

Talk about a lighter rotor

mark kibort

I know, huh? only 19lbs. I think new, they are 24lbs each!

can you believe, 23.5mm thick??? I serched high and low for a rotor like this, directional that could start out as 28mm, but 330mm. nothing out there. it is a real situation this gal got into. some idiot just kept on listening to her to slap on pads and clean up the rotors. I guess she was going to change them when she felt the grinding on the inner air vents .

xschop

Mark, are you sure you have a front Cayenne rotor that you are mocking? Reason why is I was looking over rotor specs and came up with a Cayenne REAR rotor dimension of 330 x 28 x 74 offset.

Edit: I just noticed the correct vanes in the rotor of your pic. What people will do to save a buck never ceases to confound.

VT928

Came across this info on the Corvette caliper, PBR looks like has a significant relationship with GM both in the US and Austraila. They also do the 6 piston Z06 caliper. The brochure explains the benefits of the caliper design well.

Paul

mark kibort

Yep, i think now, im 99% sure, as it is directional, so it has to be front or a 2002 911 turbo rea, or cup car rea rotor or something like that. but, it would have the eBRAKE surface on the inside and this one doesnt. PLUS, the offset is cayanne. (or VW Touareg in this case. both the same ) anyway, its a 69mm offset like the spec, it just wore out to unbelievabe dimensions. 23mm!!! can you believe that???? supposidly, Goodyear did the work for the girl. she must have kept insisting to just put on pads! . Unless someone can find another 330mm rotor that is 28mm thick an directional, i have the right one. anyway, im basing the mods on the spec, not my mock up.