JRitt@essex

Hello Gents,
We (Essex Parts Services) are the exclusive importer and distributor for AP Racing competition brakes in North America. We are now offering AP Racing Heavy Duty J Hook discs for the 996 GT3 platform. As many of you know, AP Racing discs are widely considered the most durable option in professional racing. Over the years they've won countless races and championships in ALMS, NASCAR, DTM, Rolex, etc. AP Racing has also won over 750 Formula 1 races with their brake and clutch products.

We are using the same designs, materials, and attachment mechanism for these discs that we use in pro racing. As such, these particular discs are far more stout, and will offer superior performance and longevity vs. other available options! They have 72 directional vanes (most competitors use 48), and highly crack-resistant metallurgy. They still shave roughly 4 lbs. of unsprung weight per side, despite their robust design.

The first sets will start shipping today:
350x34mm Front: Retail $1498 per pair, iron replacement rings $349 each

You can see them on our website here: http://www.essexparts.com/shop/brake...disc-pair.html

We also have the rear 997 GT3 disc, which many 996 GT3 owners run with a caliper spacer:
350x28mm Rear: Retail $1498 per pair, iron replacement rings $339 each

I wrote this post in the 991 GT3 section which contains many of the details about the product and our company. Everything in that post essentially applies to our discs for the 996 GT3. Our goal was to produce the most durable and most available disc on the market, and I believe we've done just that.

We're also working on the web pages for these specific discs, and they will be done soon. In the meantime you can get a feel for the product by viewing our other exotic applications here.

Please shoot me a PM, email me, or call me at seven-zero-four-824-6030 if you're interested in a set of these discs.

Below is a pic of our front 996GT3 disc installed on the car, and a comparison to some one-piece ATE discs on a scale.

orthojoe

FWIW, Jeff asked me to test these rotors on my 991GT3. I've been very happy with them. The ring replacement costs are also much lower than entire OEM rotors.

541 track miles and 5 track days (2 at Thunderhill, 2 at Laguna, and 1 at Sonoma) and they still look good and have performed flawlessly.

Clark-ApexPerformance

For those of you considering AP discs....we are a stocking dealer and have chosen to partner with
Essex on AP rotors/hats and Ferodo pads.
We believe both AP and Ferodo to be superior products.
Call me with any questions.

gman3280

Do these discs work with stock brake pad shapes?

+1 for Clark at Apex

JRitt@essex

Yes, these discs are designed to work with the standard OEM pad shape.

cfjan

Do the rear hats allow the use of handbrake?

Clark-ApexPerformance

Yes the AP rear hats allow full operation of the handbrake, unlike PFC who has offers no hat that will accept the handbrake.

cfjan

Thanks. That's good to know!

Can you put the 355mm rings on those front hats instead of the standard 350mm? (Even better if AP makes a 360mm ring) That's what Alcon does for the 996.2 GT3, I think? (using 5mm spacers on the calipers)

Clark-ApexPerformance

Not sure but I will find out.

AudiOn19s

Should be able to. The 355's are only 32mm thick not 34 like the OEM 996 GT3 rotor.

the 360 x 34 would be better if you wanted to go bigger. Be aware our calipers don't space out exactly even on the front there's a bit of an angle to the dangle and anything bigger than the 360 might be too much to space the caliper.

Wrightwood used their own hat with a small spacer and AP 360mm rings for the rotors they sold for our cars.

I was happy to see the 350mm ring pop up on the Essex site a few months back, previously I could only find the 355 and 360 as well but I think the 350 is the way to go at least for me.

I just put cheap Cayenne rotors back on my car for now though, until they are done I'm leaving them in place.

cfjan

Yeah, I understand that our calipers are not exactly mounted radially. But 360mm setup seems to be pretty common, so I assume that pushing it out 5mm isn't a big deal.

Been running the cheap Cayenne rotors myself as well, but it is always cool to find more alternatives, especially if they are higher performance!

JRitt@essex

Hello Gents,
I'm assuming that you're looking for more heat capacity, and that is the reason you'd be interested in going to a larger diameter? My advice is to try our 350x34mm discs as they come. My hunch is that you will be absolutely stunned by how well they work, and how long they last vs. other discs of similar size. Not all discs are created equal. These discs flow an incredible amount of air, and they're all about efficiency. As a general rule, you never want more brake disc than you need. Anything bigger than necessary is dead weight to spin up and slow down. Bigger discs provide a cool look, but they drain performance in many areas if not required.

Also, when you start adding caliper spacers, you're adding complication, and possibly new, longer caliper bolts, etc. Try the simplest path before complicating things. I guarantee you that you will not fade our front 350x34 discs with a good set of race pads and fluid on a 996 GT3. Take it to Road America, Watkins Glen, etc...does not matter. We have 700hp vettes running our 355x32mm discs all day at the track without issue. You can see some of their comments about this type of disc on our blog. The new 350's are slightly smaller in diameter, but the have a little extra beef in thickness. We drew them from scratch, and they are designed to be extra stout.

Also, please do not make any assumptions about mixing and matching discs and hats. In most cases hats and discs are deigned to work together. The attachment mechanisms can be drastically different, and most manufacturers have about six different attachment mechanisms within their own lineup. Multiply that by the number of manufacturers...and, well...you have a big mess on your hands.

cfjan

Yeah, no real reason for me (can only speak for myself). Just seems that it would be cool to go a little bit larger, consider the 997 generation cars run 380mm.

AudiOn19s

So you are saying if someone bought the 350 mm discs here and wanted to replace the rings with 360 mm AP rings next time they wouldn't be compatible with the 350mm AP hat???

JRitt@essex

To which specific 360mm discs are you referring? If you're talking about the CP3784-128/129, then no, our hats are not compatible with those. The PCD on that disc is different than it is on our 350x34mm CP7172-102/103GA.

PCD

The primary issue that you'll constantly run into with trying to make one disc fit with the hats from another disc is a difference in PCD (Pitch Circle Diameter). The PCD of a disc is the distance between the center of the mounting holes on the opposite sides of a disc. It is typically shown in mm. Here's a pic as an example:



If the distance between the center of those holes on the two discs under consideration is not identical, then a given hat will not be centered on those two discs in the same manner. On a floating disc, the whole point is to allow the disc to have freedom for expansion when it is heated. Here are a couple of pics from our website showing how this works with the attachment mechanism we use:









If the PCD of two discs are different, the bobbin will not be perfectly centered in the oblong hole on the disc flange. That means it won't slide smoothly, can bind up, cause stress risers, cracking, etc. Basically, your floating disc will no longer be floating!

Floating Mechanism

Another issue you'll run into is that the floating mechanism used on particular discs can be quite different. That is within a given manufacturer, and across manufacturers. That is why you can't slap Brembo iron on an AP Racing hat and vice versa. Some used bolted/fixed hats, where there is no float. Some use a float-in-hat (the bobbin slides in the hat rather than the oblong channel in the iron), rather than float-in-disc. Some mechanisms have twice the number of attachment holes that we have. Some have fewer. There are tons of variations, and they all have different intended purposes, strengths, and weaknesses.

The mounting system we use has been proven countless times in pro racing, is simple, reliable, and inexpensive. It doesn't have a million pieces to keep track of, is quick and easy to assemble, allows a great deal of float/disc expansion, doesn't rattle and make noise...it's a great setup.

Finally, the 360x34mm discs to which I linked above are a 48 vane design with curved grooves, a 16mm air gap, and a mass of 21.1 lbs. Our 350x34's are 72 vanes with J Hook slots, a 19mm air gap, and a mass of 20.7 lbs. Ours have almost the same thermal mass, but they're designed to flow more air and distribute heat across the disc face as evenly as possible. They're the same core design that has been used to win Le Mans many times (and will be run again there in 10 days), have captured the NASCAR Sprint Cup championship for most of the years in recent history, etc.

Hopefully that clarifies the issue of swapping iron disc rings and hats. There's a lot more to think about than is apparent at first glance, and there are fortunately reasons behind all of the design decisions in an AP Racing disc. They're not just lumps of iron...they're carefully considered lumps of iron!