Interesting new Porsche/Wilwood brake option

[RallyJon]

I've been talking to a guy who's just started putting together brake upgrades based on Porsche calipers and two piece (aluminum hat, iron rotor) Wilwood discs. I e-mailed back and forth with him and he can do anything from ~300mm discs and Boxster calipers for 15" wheels on up.

He's got a set using 993 calipers on Ebay now:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=7910674312

No affiliation--just an FYI, since I know there has been a lot of discussion of how Porsche brake upgrades are often limited by the stock rotors.

[Bill Verburg]

That'll work but you still need the 965 rear calipers and 23.8mm m/c

[RallyJon]

Sure-- the rules of choosing calipers still apply.

I just think it's great that a) there'll be a company putting together kits like this--really offering options where there were very few before--and b) FINALLY providing decent two piece discs for brakes other than the 930s or Big Reds.

The components have always been out there: cheap used calipers and good quality aftermarket rotors. It just takes someone to spec out the right aluminum hat and machine the proper adapter.

[Weaver]

I think I'm going to get ripped on for posting this but, here it goes.

The photos I see I think show a Grade 8 button head and possible a non-locking nut to attach the hat to the rotor. I can not tell if this grade 8 bolt is fully threaded or if it has a shank? The length of that bolt straight from the manufacture would lead me to believe that it is fully threaded, and has no shank.

When I bolt ally hats on to steel rotors ( or when I use ally hats and carbon rotors or Ti hats and steel rotors ) I MUST use NAS or MS bolts with a shank length that indexes both hat and rotor. This means that a NON threaded surface is taking all of the shear load during braking. It does not matter how many bolts you use, if they have a lower shear rating, they will all fail at the same time. I've seen it on cars as small as Sports 2000 and as big as tube frame GTO cars. I've seen plenty of bolts shear with only two threads of grip exposed in shear, some of these were just in a shifter linkage! I just don't think a grade 8 bolt is strong enough for repetitive use.

I just think, for a bolt that will almost never get inspected, you will want to use as strong a bolt as possible. I remove and inspect brake componets every week and crack test hats on every rebuild. Street cars never get inspected that throughly.

I would also use a NAS self locking nut, or more commonly refered to as a K-nut or a jet nut. They are self locking, I've only seen one back off in 11 years, and withstand as much as 1400 degrees. Thread it and un-thread it only 3 times though, after that, throw it away. I personnally only use k-nuts twice, then they hit the garbage. Hey, I don't pay for them!!

Are these floating hats and rotors? They will warp if they see track type temps, maybe not on the street, but after a day at Mid-Ohio, they are done. Then again I seemed to be warping front rotors on my Toyota Tundra at a rapid rate, on the street.

I am NO expert, I'm not an engineer ( but I find and correct their mistakes everyday!) , I'm just a mechanic. But these are my concerns about the photos I see here. Maybe its overkill, maybe I'm just really anal, but this is a street car application. Overkill is ok.

It does look like with alittle upgrading this would be a cool conversion. Wilwood does make some nice stuff. So does Colman (rotors) for lighter applications.

OK, let the bashing begin!! If I'm wrong about this product or my thoughts, that cool, set me straight.

Take care

[RallyJon]

Why would you get ripped for posting that? Sounds like good comments to me. I'll e-mail the guy and tell him to look at this thread.

One question: are you saying that floating rotors are MORE likely to distort from heat in extreme applications than stock 1-piece cast iron rotors?

[Weaver]

No, sorry. Just the opposite. A rotor will distort much more if it is rigid to the hat. A rotor will grow with heat. If it is directly bolted to the hat and the temp gets high enough, it will find another way to keep growing. This means the surface will start to get wavy because it has no where to go radially. Does that make any sense? A floating set-up will still warp, it just takes a much higher temp. We would warp rotors on CART cars at temp spikes of around 700C or about 1300 degrees.

[Randy Webb]

What is the advantage of these units? I thought Wilwood had some lighter rotors or lighter hubs than stock, Al hats for the rear.... Is any of that involved?

The bolt concerns make sense to me. You'd think that PAG would put some metal tabs or bosses on the assembly so that little or no shear would affect the bolts...

[Weaver]

Well, remember Randy, there is no reason to build up a part with extra bosses ect. if the correct hardware is used. Thats why the largest bolt you will find on an open wheel racecar is a 5/16". I would have no problem standing under my truck if it was suspended from the ceiling with one NAS 624 series 1/4" bolt in shear tension. Now my wife on the other hand.....

That why, with the proper hardware, this would be a nice setup IMHO.

Intresting topic....

Take care.

[KobaltBlau]

Jon, did you get the dimensions of the rotors he is using with various calipers, including thickness? For example, the set he has on ebay?

TIA

[RallyJon]

I would have no problem standing under my truck if it was suspended from the ceiling with one NAS 624 series 1/4" bolt in shear tension. Now my wife on the other hand

I think my wife would have a problem if I suspended her from the ceiling with one NAS 624 series 1/4" bolt in shear tension.

KobaltBlau, I believe his kits that use Porsche rotors must use the same thickness rotor as the caliper is designed for. I know that Wilwood's calipers can accommodate up to 41mm thick rotors.

[JeremyD]

Good info weaver...

[}{arlequin]

I always thought that someone should be making "upgrade" rotors for the stock 911 brake systems. Stoptech seems to have a good reputation and if they can design a fade-free system for high hp Vipers, they must be doing something right. They already have OEM replacement rotors for different makes. Maybe even the $$ for Stoptech rotors would be worth it if their rotors really do have a higher thermal capacity than OEM replacements.

[Randy Webb]

How much wt. savings is there with the Al hats??

[Bill Verburg]

When fabbing brakes there are several potential pitfalls, among them are inadequate hardware, another is using the wrong aluminum alloy for the hats and adapters.

Randy not a true comparison but
hd 322x32 w/ aluminum hat 18#
hd 322x28 one piece 19.75#

4mm thinner ~1.75# heavier

[jpahemi]

I used Forged Wilwood Superlites with (4) 35 mm pistons and the stock Carrera rotor; very nice feel.
Ok Bill tell me I messed up my bias. I did replace the regulator to the 55 bar unit (rear).
Regards,
J.P.

[}{arlequin]

on what year vehicle is this setup?

[KobaltBlau]

Originally posted by jpahemi
[B]I used Forged Wilwood Superlites with (4) 35 mm pistons

how much $? just curious.

[jpahemi]

Dave:
84 911 3.2
Andy:
$150 each + $90 for pads.
j.p.

[jpahemi]

Guys,
These can be ordered with Thermo-Lock pistons; a 2 piece piston with an insulation layer in the middle.
j.p.

[jpahemi]

Custom ss hard line.
I know Wilwoods aren't held in high regard within the Porsche circle, but these are quite inexpensive and give good results. Ultimately, the rear DOES need attention for proper bias, which lands in a Porsche brake product.
J.P.