930 size brake option for $750 using Wilwood parts???

[Elombard]

Hey Folks,

looking through braking threads I started piecing this together. Maybe its been done before:

Wilwood caliper

Wilwood High-Performance Disc Brakes - Forged Superlite Internal Calipers

3.5" mount spacing
Takes 1.25" thick rotor
4 x 1.38", 1.62" or 1.25" diameter Pistons options

Cost ~$170 ea x2 = $350

For reference a 930 caliper is just a smidge under 1.5" dia. pistons

Wilwood rotor

Wilwood High-Performance Disc Brakes - Rotor No: 160-11837

11.75" Diameter and 1.25" thick

Cost = $130 ea. x2 = $260

930 rotor is similar. Apparently these Wilwood rotors can be used as a substitute for 930 2 piece rotors

Rotor Hat from Rebel racing

brake system components Rebel S Racing Products

Cost =$130 per pair

Half way down page

These can be used on Wilwood or 930 rotors

Front brake package with the heat sink capabilities of a 930 set up for ~$750 + hardware and lines.

And!!! It might fit under 15" wheels!

I wonder what is involved to "shim" the caliper so it would be centered on the rotor?

I would like to run this set up with stock Carrera rear rotors/calipers initially and then maybe go to used 964T rear calipers and 930 rear rotors down the road.

I need to look at the balance front to rear. It has to work with either the 930 Master Cylinder or Carrera master cylinder and the brake proportioning HAS to be good for the track ~ 1.5.

Has anybody tried this? I think some of the SP911 guys are running this caliper on stock Carrera front rotors (different width and caliper pistons probably).

Bill V , KTL your thoughts?

I am just never going to be able to do a 930 set up, $5k for a want (not a need) i just cant justify it.

But I really want that heat sink capability for the track days...that I rarely have time for...

[James Brown]

interesting, it just might work. And you could spring for a porsche decal to boot!! washers can be used for shims but might need longer bolts

[rdimarco]

I've looked into this. The problem with that tab mount caliper is it's radial position on the rotor. You need a radial mount caliper and the proper adapter to get it in the correct position. I think that caliper is close enough to work on a carrera rotor, but then there would be no thermal benefit. To work with that rotor/hat combo I used a 964 caliper with the ears milled off and a custom made adapter. It fits under a 15" wheel with a 7mm spacer.

[Elombard]

Interesting so the 964 caliper supports a 1.25" thick rotor?

That is very trick that your set up fits in a 15" wheel.

What are you running on the rear? What is your brake proportion front to rear?

[rdimarco]

On the 964 front caliper (36/40mm pistons), the retaining pad needs to be ground off a bit to fit the 1.25" wide rotor (28mm stock). I used 2-piston 964 calipers (44mm pistons) on the rear to give a hydraulic F/R ratio of 1.5. The rear calipers need to be hogged out also to fit over a stock 930 rear rotor and the mounting holes need to be relocated. The rears fit under 15" wheels with a 3mm spacer. The 2 piston 964 rears give more rear bias than the 4 piston 964 rear calipers (28/30mm pistons). A carrera rear caliper (42mm pistons) would give a HBR of 1.64. The only minor drawback with the rear 2 piston 964 caliper is a more limited pad selection. I've used Porterfield R4 which worked well. Now I'm using Raybestos ST43 that was a custom pad Porterfield made to fit the 2P 964 rear caliper.

[Elombard]

That seems great. And you could add a race proportioning valve if the brake bias was too much rear. That seems like a great thing too have - too much rear brake and then you could trim it with a prop. valve on the fly.

Minimal pad selection is a drag.

Do you know who I could contact to make an adapter to mount the 964 calipers on the front? Or was that a completely custom 1 off deal?

I see VCI makes an adapter for the 964 caliper but it centered for the 964 rotor which I would rather not use.

[rdimarco]

The 964 caliper over 930 size rotors was a custom DIY job. If you are paying a shop to machine the calipers and make the adapters, I dont think it is cost effective and would just get 930 calipers if you are committed to 15" wheels. Bigger wheels are no problem, plenty of bolt-on kits available.

[Elombard]

Thanks Rick

I was hoping the adapters were off the shelf some where. I can handle everything else DIY.

[Bill Verburg]

Originally Posted by Elombard

That seems great. And you could add a race proportioning valve if the brake bias was too much rear. That seems like a great thing too have - too much rear brake and then you could trim it with a prop. valve on the fly.

Minimal pad selection is a drag.

Do you know who I could contact to make an adapter to mount the 964 calipers on the front? Or was that a completely custom 1 off deal?

I see VCI makes an adapter for the 964 caliper but it centered for the 964 rotor which I would rather not use.

It's almost impossible to get too much rear bias w/ 964 calipers

Yes, the 964 front fits over 930 32x304 rotor, here's one I used years ago stock mounting ears removed then machined for an adaptor to 3.5 struts


In back similar throat mods and redrilling of the mounts for 3" trailing arm and 930 309x28 rear rotors.


W/ 964 calipers and 930 rotors net bias is 1.692 only slightly less front than a stock 964

w/ 993 30/34 rear it goes to 1.386, I'm a little uncomfortable w/ this much rear, some do use it and even more rear down 1.2 or so, probably want an adjustable p/v in this area

w/ the 2 piston 964 rear you get 1.472 right were you want to be

[Elombard]

Thanks Bill - Yeah I was thinking the 2 piston rear - too bad not a lot of pad availability.

In the end all of this machining and custom really lowers the appeal.

I was really hoping the Wilwood caliper would work with just an appropriate spacer to center over the RSR 911 hat/Willwood rotor combo.

I wonder if it would be worth considering welding up the Wilwood and re-drilling the holes so its radially in the right spot. Heck maybe they could sell the caliper "blank" with no holes?

I would like to get one of the calipers and rotors, the RSR hats and mock it up.

If anybody has a set of 964 front calipers already modded for the 3.5" struts and 930 rotors they want to get rid of cheap let me know :-)

[dfhtrhjn]

Would any of those Wilwood options work as stock replacement calipers for the mid year cars? Maybe for the fronts?

It would be nice to have the option of new calipers in the future when I'm tired of rebuilding old calipers.

[eddie914]

I agree with RDIMARCO.

I made it work with custom hats and custom caliper adapters. As a DYIer it was well worth the time and $$$.

Cheers

[JimmyT]

This may get you a bit closer to your goal:
FS: 930 Floating Front Brake Hat Kit (930.351.457.01, 930.351.423.00),$220.18 per wheel

[Elombard]

Jimmy, is this the same type of adapter ring that Rebel sells (see link above) for a bit less or am I missing something? Those are beautiful.

Do you have a picture of a set installed and wheel off?

[JimmyT]

These kits are dimensionally identical to the 930 hats & rings, except that I used a tighter fit on the dogs (lugs). They are made from a higher grade aluminum than the OEM parts and allow the rotors to float or be fixed (for disk machining or rotor noise). They are presented as a replacement for OEM parts that currently retail at ~$807.93, although some are NLA.

The Rebel parts are a different design, employing the Coleman T-Locks. If you are looking for the cheapest path forward I would certainly give Coleman a call.

Good luck in your quest!

[Steve@Rennsport]

Originally Posted by JimmyT

This may get you a bit closer to your goal:
FS: 930 Floating Front Brake Hat Kit (930.351.457.01, 930.351.423.00),$220.18 per wheel

E-mail sent.

[Elombard]

Thanks Jimmy - beautiful stuff you make.

[KTL]

Erik,

Sorry for the late follow up on this. Awhile back last year I believe, I gathered up all the parts you mentioned in the first post. I got one Wilwood Superlite Forged Internal caliper (for 1.25" thick rotors), the Wilwood 11.75x1.25 rotors and the Rebel Racing 8 bolt rotor hats.

The rotors with hats installed on them fit very nicely on the 911 hub. The rotor bolt spacing on the Rebel hat for the Wilwood 8 x 7.00" bolt spacing is dead on perfect. Plus Clint designed it with a slight relief in it to register it on the rotor ID. So the hat fits perfectly in the 7.00" lug diameter. This is a really nice touch that ensures the rotor and hat are concentric. The rotor also clears the ball joint location on the A-arm OK. It's tight but it clears.

Now the caliper. Unfortunately the lugs/mounting ears on the caliper do not talk nice with the mounting ears on the struts. I'm going by memory here but I think the ears on the caliper would have to be machined a bit because the offset of the caliper ears is not wide enough. Stinks because it'd be OK if it was too wide because you could simply use some spacing washers to get the caliper centered over the rotor. As an aside to that spacing washer statement, a 3.5mm thick spacing washer is actually how the 930 calipers are mounted to the 911/930 strut from the factory.

I also believe the distance from the strut ears to the caliper ears is just a bit too far to get the mounting holes positioned right. I feel like the thought was some kind of offset adapter plate would be needed. My memory is sort of cloudy on that part. I would have to take a look at it again and take some darn pictures this time.

I should have taken more notes when I was fidding with installing the Wilwood Superlite Forged Internal caliper. But I know I played with it for a while in the hopes that I could realize a simple fitment. I ended up thinking it was a no-go for the aforementioned reasons. The hope for a bolt-on discovery was squashed....... So I just returned the caliper to Summit Racing no questions asked.

Incidentally I have fitted the 930 caliper over the Wilwood-Rebel rotor & hat combo and it fits nice. I'll take some pictures and show you. Unfortunately as you know, 930 calipers are a real hard kick in the nuts cost-wise, even used. Luckily I sourced a new pair of 930 front calipers in 2013 back when they were being sold reasonably cheap. I got them from Sonnen Porsche for $545 each ($959.30 currently) but even that price is still a really hard pill to swallow.

BTW JimmyT does indeed make beautiful parts and is a fantastic guy. I have one of his RSR t-stat blanks that replaces the engine's internal t-stat when you install an oil filter console in place of the engine mounted oil cooler. I also have a few of his external t-stat caps with built-in hex heads which replace the original annoying slotted caps. Also have one of his ingenious wedge bolt 915 shifter handle extensions. I just wish he had come up with the shifter handle extension before I welded an extension onto mine!

[Elombard]

Wow Kevin - over and above thanks for the detailed report.

Thats too bad. Yeah I had heard some where that the Willwood caliper would not sit in the right spot radially (too close or too far from the hub center. needing to machine the ears or the strut lugs and an adapter kills it for me.

Is there a chance that Clint could machine rotor ring to hub adapter that would allow the rotor to be in the center of the caliper when it was bolted to the existing ears on the strut? Doesn't get around the radial problem but maybe Willwood would make us a rotor of the right diameter for that scenario :-)

[KTL]

If the rotor hat was designed to push the rotor further inward, to center it in the Wilwood caliper, the rotor would hit the ball joint area on the A-arm. Basically the hat would need to be thicker to get the rotor positioned closer to the offset of the Wilwood caliper but that additional thickness will cause the rotor to foul the A-Arm

Here's some pictures of the typical early floating 930 rotors (304 x 32mm and a Rebel hat) on an '87 Carrera. Pics courtesy of the install I helped douglas bray complete. In the first two photos you can see the spacing washer between the caliper ear and the strut mount. Notice how close to the edge of the rotor is the A-arm







I took some pictures of my 11.75" x 1.25" (~299 x 31.5mm) Wilwood HD 40 rotors with the Rebel hats on them. They fit within the 930 caliper OK in terms of the rotor diameter matching the brake pads..

But I gotta understand why my calipers need more spacing washers to center the rotor in the caliper. I placed two spacing washers under one mounting location just to get the rotor well positioned inside the caliper for taking pictures (car is in pieces, not even remotely operational) and it's not actually centered. Needs a bit less spacing washer thickness. I think I can use one 930 spacing washer and a Grade 8 washer, which is about 1/2 the thickness of the 930 washer.

You can also see that my spindles are raised and that pulls the rotor up away from the A-arm (and close to the ball joint boot........ )