Fly911

I just bought an '87 911 Carrera for track and week end use, and one of the (many) mods I want to do is the brakes. I have a complete set of 993 callipers available. I know there are calliper adapters for the front that will work with 930 rotors, but I can not find any addaptors for the rear callipers. Are there anyone out there with any experience or suggestions on this?

wildcat077

You might want to go take a look on Pelican ... Bill Verburg is the resident brake guru and there are loads of posts about brakes ...

Cheers !
Phil

Amber Gramps

Too funny. I was just looking at Steve's page on this very subject:

http://www.rennsportsystems.com/1-sf.html

whalebird

Patrick motorsport maybe. Try steve at Rennsport first. I can't remember, but wheel fitment and master cylinder are a couple of issues you may want to bring up.

Bill Verburg

In front use 930 size 304x32mm rotor, oem 2 piece 930 or aftermarket, you can't use the oem 1 piece 930 rotors unless you have 930 flares too and caliper adapters(VCI is a good source).

In back its fairly easy to mod 993 rears for use w/ stock 309x28mm rear rotors. 2 things need to be done here
1) plug the stock axial mounting holes and redrill to fit the 911 3.5" mounts
2) grind the throats a little, the 993 rears are designed for 24mm thick rotors the 28mm 930s need a little more room.

They will look like this when done

g-50cab

Steve at Rennsport makes cut down twin turbo rotors and hats. Caliper adapters are available from VCI and Road and Race and a few others - as Bill mentioned - rears are filled and redrilled over 930 rotors (which maintains emergency brake) better yet are 965 rear calipers - they have the thicker throats to accomodate the 930 rotors

my 965 calipers


Front with Steve Weiner's rotors

Bill Verburg

Notice how close the holes are to the edge of the rotor? Think about it.

Steve Weiner-Rennsport Systems

I'd kindly suggest that you speak with the people who race with these rotors and ask them about any cracking issues they have.

Real world experience may be educational.

Bill Verburg

Steve, I have plenty of experience w/ those rotors in unmodified form, they crack out well before they wear out, I get at most 20days on a set. Having the holes that close to the edge is not going to increase longevity. If you want to sell them and folks want to buy them, fine. It's a free market, but it is worth thinking about.

Steve Weiner-Rennsport Systems

Bill,

With all due respect to your experience with those, I too have some long-term background with these on a wide range of race, DE and street cars over the past 7 years.

FWIW,...To date, everyone using these gets anywhere from 2 years to 4 years on rotors, using Pagid race pads of all kinds and proper cooling. The ones that show some light cracking after a year or so of racing, do not crack to the edges, like they LOOK like they might do. We would not offer anything that compromises durability, however we are quite careful to ensure everyone using these for the track has adequate cooling as thats one of the main keys toward controlling peak brake temps. Excessive front bias also contributes to rotor cracking issues as I'm sure you well know.

My only point was to caution against wide generalizations without having first-hand experience with a specific product,....

Amber Gramps

Steve, Are your rotors pictured in this post? Love them.

http://forums.pelicanparts.com/porsc...ml#post5937935

Steve Weiner-Rennsport Systems

Similar, but not mine.

whalebird

I too have been concerned with cracking. I've experienced a few track cars that would start cracking early on in their service life. Decent venting was in place (with temp paint)and on 964s with big reds. At a glance the rings (of saturn) were normal, but appeared after the first couple of days. At closer inspection the cracks were there and seemed to propogate quickly. IIRC, Porsche recommended replacement of the rotor when these cracks reached 2mm and that seemed to be where the cracks stopped. They worked fine after that, but was a concern. Again, IIRC frozen rotors performed about the same.
In the context of this thread, is my experience consistent with others? When is rotor replacement warranted; Crack length?
Just curious for my own edification and perhaps that of others here.

g-50cab

REAL WORLD EXPERIENCE ---> I have yet to replace mine - my friend also has a set and just replaced his first set. Yes there was cracking and propagation at the holes - but not at the holes that were at the perimeter - more cracking was evident at the center of the disk - and again - less than 2mm - more like 1mm and stopped.

He had well over 20 track days on his carrera - at Sebring - which is brutal on brakes. I only have around 6 track days on mine (again at Sebring) and those were with a 2.7 where most of my challenges were getting my brakes up to heat. SO much so - that I actually ended up going back to a street pad...

Fly911

I have received two interesting quotes from Patric Motorsport:

One using 993 Turbo front callipers and floating rotors, and special rotor hats for the 993 Turbo rotors. And 964 or 993 rear callipers machined to fit the 911 trailing arms, with 930 rotors. The set up is quite expensive, but probably the best you can get (unless you buy a complete set of new Brembo brakes for twice the price).

The other one is with used Boxster callipers and cross drilled (84-89) 911 rotors on all four. A cheaper alternative than the first one, but also smaller brakes (but probably good enough for a light weight 911).

My "dilemma" is that I already have a set of 993 C2 callipers available, and they don't fit with the front set up from Patric. The 80-89 930 rotors have the same dimensions as the 993 C2 rorors, 304mmx32mm. Do floating 930 rotors exist, and if so, would the rotor hat for the 993 Turbo rotors fit a 930 floating rotor? If so, I would be able to use the 993 C2 callipers all around, and save close to $1,500. I will ask Patric Motorsport...