Gauging Interest:New for 2017 Essex Designed AP Racing Radi-CAL Competition Brake Kit

[JRitt]

Hello Gents,
I hope all is well in 86 land. I just wanted to check in and gauge interest on a new product idea we've been kicking around. We've been working with AP Racing over the past year on the development of a new Radi-CAL Pro5000R caliper. It's an ultra-lightweight (4.8 lbs.) forged four piston, with ventilated, domed-back, stainless steel pistons with anti-knockback springs. As with all of our calipers, it uses a commonly available pad shape. These calipers are the state-of-the-art right now, and have had a huge impact in pro racing. There isn't anything else like them in the market at any price. You can learn more about them in this blog post: The AP Racing Radi-CAL Story.

Below are some shots of the new caliper when used in its rear configuration (CP9449/50/51). The front version will look essentially the same with different piston sizes.



[IMG]http://cimg9.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/800x533/80-20161121_cp4994_pro5000r_7_3_726ec621***aa3071eb48 6bbe80937643e4c89cd.jpg[/IMG]

[Racecomp Engineering]

Sploosh.

- Andrew

[gramicci101]

Jeff, how would this compare to the Sprint and Endurance kits? That's an interesting piston design; are there any negatives with having the leading edges scalloped like that?

[CounterSpace Garage]

It's about time!!!

[JRitt]

Okay...now here's the part we need help with. We're trying to decide what size/type of disc to match up with these incredible new calipers. We've been discussing various options internally. I'd like to know what people want. Regardless of what size we go with, it will be a stout AP Racing J Hook disc, just like we sell in our current Sprint and Endurance Kits.

Option A: The same 299x32mm disc that is being used in our venerable Sprint Kit. At first glance this disc seems small, but we've won tons of races, events, set records, etc. all over the world with this tough little disc. One of the best features is that is very inexpensive to replace. We've had them on plenty of cars with 350 or more WHP, and it's very rare that anyone can fade them on the 86 chassis.

Option B: Increase the disc size to 310x32mm. This setup would offer a little more thermal capacity, without a huge weight penalty. It only weighs about a half a pound more than the 299mm disc in Option A. Wheel fitment really wouldn't be impacted at all with this setup vs. the Sprint Kit. In some cases, wheel fitment would actually improve, because the spokes curve inward as they get closer to the hub.

Both of the above kits would likely retail for a price in the mid $2000 range. Maybe something like $2599, like our current Endurance Kit. I haven't run the final numbers yet, but it's likely going to be close to that number.

Option C: Increase disc size to 340x28mm. Because this disc is narrower (28 vs. 32mm), the weight is nearly identical to the two discs above, despite its larger diameter. Wheel fitment would definitely be impacted vs. our current Sprint Kit. Because the disc is narrower we'd be able to pull the caliper inboard a little bit. However, there wouldn't be as much wheel barrel clearance on 17's because of the larger diameter. The big difference with this one is that these discs are considerably more expensive. These discs would push the price up to the low $3,000 range.

At this point I'm leaning towards Option B. Given the amount of abuse our 299mm discs have proven capable of handling, I'm thinking a 310mm kit with the Radi-CAL would be the ultimate solution for about 95% of our customers. A kit in that configuration would weigh about the same as our current Sprint Kit (20 lbs. less than the OEM front brakes), while offering a bigger disc with a little more thermal capacity than our current Sprint Kit. The Radi-CAL caliper technology would provide superior pedal feel due to stiffness, and offer better cooling due to the body and piston design.

Please let me know your thoughts, and thanks as always for your input!

[JRitt]

Originally Posted by Racecomp Engineering

Sploosh.

- Andrew

Hahaha...OMG...you literally made me laugh out loud on that one!

Jeff, how would this compare to the Sprint and Endurance kits? That's an interesting piston design; are there any negatives with having the leading edges scalloped like that?

See disc options above in my second post for a comparison to our current kits. There are absolutely zero negatives to the scalloped/ventilated pistons, but lots of benefits. The scallops allow air to flow behind the pad backing plate and into the body of the piston. They help significantly with cooling the piston walls, brake fluid, and caliper body. The other sneaky-cool feature about the pistons in the Radi-CAL's is the domed back. Having a curved back significantly increases stiffness, and the pro drivers all noticed the change immediately when that design change was implemented on the Radi-CAL calipers in NASCAR Cup, IMSA, etc. The domed back gives better pedal feel. They also keep the same style anti-knockback springs used in the CP8350. The pistons in the Radi-CAL are just a more advanced design.

It's about time!!!

You're tellin' me brother! We've been waiting on these calipers for quite a while. They were a clean sheet design, and we spent a great deal of time spec'ing them out with the AP engineers. Fortunately, the final product was worth the wait. The first batch of rears is inbound, and we're launching rear kits for a whole slew of cars...e92 M3, F80/F82/F87 M2, M3, M4, C5/C6/C7 Vettes, Porsche 986/987, etc. We're still a little ways out on the front variant, but we want to plan accordingly and get the design work underway for an 86 kit if there is adequate interest. I'm assuming there will be, as these new calipers are Ridonculous! People freak out when they hold them in their hand for the first time...and then a little more after they drive them.

[Vracer111]

So this new caliper weighs the same as the CP8350-2S4L/3S4L in the sprint kit? Was hoping they were lighter....

Glad I've held off on doing anything for suspension and brakes yet....almost ready to begin making it ready for track use...

I'd be most interested in Option A... dropping unsprung mass is a top priority to me along with as low consumable cost as possible.

[JRitt]

Here are some other Pro5000R Radi-CAL kits we've designed on other cars to give you an idea of what they look like mounted up. Some of these are prototypes of the kits we are releasing over the next couple of months, hence the raw aluminum disc hats:
C7Z06




e92 M3


BMW M2




BMW M4


S197 Mustang


Shelby FP350S (soon to be released by Ford)



Nissan GT-R


Porsche 987 Cayman


VW Golf GT Mk6 and 7


These aren't from the Pro5000R range, but they're all running a different variant of Radi-CAL, and they are gnarly cars...had to share. Some of these pics are from the Rolex 24 at Daytona last weekend.

Lexus RC F GT3


Carbon body before wrapping...


Porsche 911 RSR...took second in GTLM class last weekend.


Okay...you can't see the Radi-CAL brakes in this shot of the 911 RSR, but I just had to post it.


Corvette C7.R


BMW M6 GTLM

[churchx]

Woah. JRitt: stop posting porn pictures.

[Vracer111]

I was at the Rolex 24 too, but brakes were furthest thing from my mind, other than getting shots at the brake zone before the oval section:



Too bad the lexus team didn't do that well, pretty cars though. Still need to find time to sift through all the photos and video I took.

[Ro_Ja]

Just take my money.

[RJasonKlein]

@JRitt you're a man of your word! For the rest of you, Jeff and I exchanged e-mails a few days ago when I inquired about about the possibility of developing a Radi-CAL Pro5000R kit for our cars, and he said he'd survey the forum to gauge interest.

Obviously, I'm on board! Option A or B would work for me, but I think option B offers the broadest appeal. At around $2,600 I can put a deposit down on a kit now.

[JRitt]

Originally Posted by Vracer111

So this new caliper weighs the same as the CP8350-2S4L/3S4L in the sprint kit? Was hoping they were lighter...

Prior to 'Radicalizing" their calipers, each successive generation of AP Racing caliper would gain something like 3% stiffness due to further design optimization. With the patented Radi-CAL design, AP was able to increase stiffness over 30% vs. a conventional caliper of the same basic form without adding any weight, and in many cases reducing weight. That is without resorting to any exotic materials. In engineering terms, that is an almost unbelievable accomplishment, and a massive leap forward! After their first round of testing, the improvements were so dramatic that their engineers actually had to recheck their data to make sure there wasn't an error in the results.

If you look closely at the caliper, there really isn't a way to make it much lighter. Look at all of the gaps and voids where material would normally be, like the big holes between the pistons. The Radi-CAL calipers are basically a skeleton. They provide the structure and support only where required, and any superfluous material is stripped away.

The only other possible way to further reduce weight without changing the materials used would be to make it a monobloc and eliminate the four bolts that hold the two caliper halves together. That's what AP does in NASCAR for example, and the calipers look like the one below. In that case however, the caliper becomes painfully time-consuming and costly to machine/manufacture. They also use titanium pistons to further reduce weight, but they cost $5,000 each, and that's just for the caliper!

While the monobloc is inherently lighter due to the lack of through-bolts, that doesn't automatically make it any stiffer, which is a big misconception among many enthusiasts. With the monobloc, in many cases you must remove the caliper to change pads, which is obviously far from desirable to most of you on this forum!

[JRitt]

Originally Posted by Vracer111

I was at the Rolex 24 too, but brakes were furthest thing from my mind, other than getting shots at the brake zone before the oval section:

Too bad the lexus team didn't do that well, pretty cars though. Still need to find time to sift through all the photos and video I took.

Sweet! I'm jealous...would have loved to have went. Nice pic!