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      09-24-2014, 12:00 PM   #177
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Quote:
Originally Posted by j.lecram View Post
Any chance Essex's going to put together an AP Racing ENDURANCE kit for our E9x M3s, as you did for the C6 Corvette?

With the weight of our cars, it seems the current COMPETITION kit available is more akin to the C6 SPRINT kit. If we could get the kit with rotors in the 368-378mm range, we should still be able to fit it under many 18" wheels but have the added benefit the larger rotors would offer. It would look a bit like the AP Racing setup on the M3 GT4. Now that would be nice!
What exactly do you plan to do with your car that would make you think the discs in our kit aren't adequately large enough? Also, what are you basing your assessment of the disc size on? Are you simply assuming that because the M3 GT4 has larger discs, our kit isn't large enough? I'm not trying to be confrontational, I just want to understand your perspective.

All real world data, including professional racing experience on a wide array of cars, and feedback from actual customers on both platforms suggests that our discs are indeed very appropriately sized to provide a long service life for these platforms while removing the maximum amount of unsprung weight.

A C6 Z06 weighs approximately 3200 lbs., has about 500hp and tq., and typically would be running a 305 width front tire on track. It's also arguably easier to achieve superior aero on a C6 Vette.

An e92 M3 weighs 3400-3500 lbs., has 100 less hp and far less tq., running a considerably narrower front tire, and likely won't be as slippery.

Despite the 200-300 weight difference, the vette is going to be far harder on the brakes. All else equal, it's going to be going a lot faster at the end of the straight. More speed = more kinetic energy transferred into heat. I addressed this issue on the first page of my post...not sure if you caught this or not. It mentions weight vs. speed, and the impact on brakes (see below).

As another example, did you know that the biggest discs we sell to NASCAR Sprint Cup teams are only 328mm in diameter? Those cars weigh about the same as an e90 M3, have about 900 hp, and run fat slicks hitting 200mph. At a road course like Watkins Glen, they are absolutely devastating on brakes!

Therefore, I believe our Endurance Kit for the M3 is every bit as much an Endurance Kit for these cars as it is for Corvettes. We have yet to see anything to the contrary.

Huge discs look pretty, but come with significant penalties. Our design philosophy with these kits is essentially, anything more than is required is too much. Why drag around an extra 5 lbs. per corner of dead weight if it's not needed? Now if you told me you were going to run a 24 hour race, then I'd say, "Sure, you could probably go a little bigger." That's why the GT4 has larger diameter front discs, but that's not something most of our customers plan to do however. Also, please note that they're only running 355mm discs on the back of that car, despite running 24 hr. races.

Hopefully that all makes sense.

Quote:
Q: Why aren't the discs bigger?
A: Short answer: Because they don't need to be! Long answer: Our systems are built from a racing mentality. In the pro racing world, teams scrap and scream to remove ounces of weight from the cars. Anything that is larger than necessary to get the job done is simply dead weight to drag around. That is how we approach our design. If you want to go faster and a 14" disc will work, a 15" disc will simply add weight, increase the moment of inertia, and hinder wheel fitment. Sure it will look pretty behind 20" wheels, but that's not what this product line is about.

The 14" AP Racing CP5773 Heavy Duty J Hook discs we are using are the exact same discs that won the championship last year on the Action Express Corvette Daytona Prototypes. These discs are being tortured in endurance racing events every weekend at the hands of some of the top drivers in the world. Yes those cars are significantly lighter, but they're also significantly more powerful, and far faster. To give you an idea of the boundaries they're pushing, one recently hit 223 mph in testing! :O If you think you'll give these discs a harder workout in your 20 minute DE session than these guys will when running 24 Hours of Daytona...no offense, but you're probably wrong. Keep in mind that the amount of energy transfer (changing kinetic spinning energy from the disc into heat) in a braking event is most greatly impacted by speed....more so than by weight. I'm going to get a bit technical here, so feel free to skip ahead if you feel your eyes glazing over! The core formula for kinetic energy is:

kinetic energy = vehicle weight x vehicle speed2

Take note of that little superscript at the end. If you look at the equation above, you'll note that doubling the vehicle's weight would double the kinetic energy, but doubling the vehicle speed would increase the kinetic energy by a factor of four! So in plain English, that means a stop from 220mph on a lighter car is going to be tougher on the brakes than a stop from 140mph on a substantially heavier car.

When comparing discs, you can't simply look at the diameter and decide that one will be more effective than another. The number of vanes, air gap, wall thickness, vane shape, metallurgy, hat attachment design, etc. all have to be taken into account.

To give you another example, our small four piston C6 Corvette Kit has found its way onto quite a few C6 Z06's pushing 600hp at the track. That kit features a 325x32mm disc. The OEM front disc on a C6 Z06 is 355x32mm. With a disc that is 30mm smaller in diameter than stock, many of our customers are seeing huge increases in pad and fluid fade resistance, less disc cracking, longer disc life, pads that wear longer, etc. Again, it's not just disc size that matters. It's all about design and optimization.

Wheel fitment is also of critical importance in our design process. As mentioned above, most of our customers run the smallest, lightest wheels available for the platform. I won't go into all of the merits of doing so, but obviously unsprung weight, lower rotational mass, cheaper tires, etc. all factor in. Our systems are packaged tightly to allow for a wide range of wheel fitment. Using an extremely large diameter disc kills wheel fitment, and the utility of a track-optimized brake system.

Okay...I've beaten that one to death.

Last edited by jritt@essex; 09-24-2014 at 12:06 PM.. Reason: Added info
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      09-24-2014, 11:13 PM   #178
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I think I know where you're coming from, Jeff. But still, are you planning on making a bigger kit some time in the future? For me it'd be worth waiting for since what you're putting together is a work of art!
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      09-25-2014, 07:14 AM   #179
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Quote:
Originally Posted by j.lecram View Post
I think I know where you're coming from, Jeff. But still, are you planning on making a bigger kit some time in the future? For me it'd be worth waiting for since what you're putting together is a work of art!
Thank you. I appreciate the nice comments.

If people want a kit with bigger discs, we will consider building it. As I've mentioned in this thread several times, we want to provide our customers with what they want. Sometimes people don't know what they need, and require guidance. Other times they just want what they want, which I totally understand. I've been there many times myself.

So, if you've been seriously considering buying one of our kits but the smaller disc size is holding you back, shoot me a PM or email me and let us know. Thanks gents.
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      09-25-2014, 04:35 PM   #180
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Jeff, I am fine with the disc option, but I wish you used a cheaper pad with more volume. I have a similar pad in my ST60 kit and if I try hard enough, I can blow through a set of pads pretty quickly, and with replacement pads costing north of $500 they are expensive to run.
I know there are limitations with what can be produced, but are there any plans for thicker pad option like your 4pot kits?
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      09-25-2014, 10:33 PM   #181
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That would be great, Jeff. A kit just like the one you've put together, but then with front discs in the 368-378mm range (rears at approx. 355mm) and with an APR Pro 5000+ series caliper that would take 25mm pads would be an amazing setup for more endurance oriented applications.

I will PM you about this later. Thanks for being open to this possibility.
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      09-26-2014, 12:38 PM   #182
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Understood gents. Thank you very much for your input.

Quote:
Jeff, I am fine with the disc option, but I wish you used a cheaper pad with more volume. I have a similar pad in my ST60 kit and if I try hard enough, I can blow through a set of pads pretty quickly, and with replacement pads costing north of $500 they are expensive to run.
I know there are limitations with what can be produced, but are there any plans for thicker pad option like your 4pot kits?
Understood on the pads. A couple of further notes to consider on our setup vs. the ST setup you're running now. ST uses the same basic pad shape as our AP Racing calipers (it's originally an old AP Racing shape). They use a D51 radial depth however, while ours is a D54, which gives our kit a bit more pad volume (although admittedly not a great deal more).

The bigger issue would be with the discs however. If you're running a high vane count disc like the one in our kit (72 vanes vs. 48 vanes), you're moving more cooling air, your discs temps are going to be lower, and your resulting pad wear rates will be decreased. All of the components in the system work together towards the end result.

That said, I hear you on the 25mm thick pads. One of the big problems that comes into play when going to calipers that use pads that thick is wheel fitment. When going from an 18mm thick pad to a 25mm, you're typically losing most of that 7 mm on wheel spoke clearance. When we designed this kit, we took that into consideration, and felt that the superior wheel clearance was worth the tradeoff for most of our customers, considering how they use their cars. Again though, that's not obviously the case with everybody.

Quote:
That would be great, Jeff. A kit just like the one you've put together, but then with front discs in the 368-378mm range (rears at approx. 355mm) and with an APR Pro 5000+ series caliper that would take 25mm pads would be an amazing setup for more endurance oriented applications.

I will PM you about this later. Thanks for being open to this possibility.
Understood, and no problem. We want to make what our customers need and want. While we obviously can't have 47 different brake kits per platform , but I'm not opposed to multiple kits for the same platform. We're already doing so on a couple of the existing platforms that we service.

If we did a kit with a bigger disc, it would likely be tied to a thicker pad as well. So you'd be getting a significant increase in thermal capacity from both the pad and disc in the same kit. If we go down that path, maybe we'll call it our "Obscenely Overkill" big brake kit, or our OOBBK.

Also a note...It's going to be tough to fit anything much bigger than a 362mm disc inside an 18" wheel. Our Factory AP Racing BBK for the Corvette uses a disc that size, and the caliper is literally grazing stick-on wheel weights on the barrel of the wheel. Keep in mind that you still need enough room to drop a caliper on top of the disc. The shape of the caliper, pad retention mechanism, etc. all come into play, so what works for one manufacturer's setup on a disc of X size, may not work with a different caliper.

Behind an OEM C6 Z06 18" wheel


Behind an aftermarket, multi-piece 18" wheel
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      09-27-2014, 12:32 PM   #183
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On the front, an AP Racing 5260 caliper with 25mm thick pads on a 368mm disc clears the wheel barrel, at its tightest point, by a 13 mm margin. This is on an Apex EC-7 18”x10” ET25 wheel (a fairly typical track-oriented application). It should also easily clear similarly track-oriented 18” wheels. So it should be feasible to go to an even larger disc without too much worry.
The template for this particular combination is downloadable from the APR website. This combination should also clear the stock 18” wheel with a 15mm spacer. Most of us would not be running stock wheels at this point, however.
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      09-29-2014, 09:20 PM   #184
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Addendum to my previous post: the aforementioned setup has the discs at 36mm thick.
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      11-04-2014, 07:57 AM   #185
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how does changing between a street pad and a track pad wear on the rotors? is it possible that one of the two will embed differently and cause some shudder, vibration, or uneven wear?

also, in the original post, the rotors on the m3 and the rotors on the corvette appear to be a little different. the m3's design doesn't have the hat cutouts (or maybe its the rotor?). but it says the m3 kit will look exactly like the vette kit. any clarification on this?
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      12-01-2014, 02:19 PM   #186
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Quote:
Originally Posted by roastbeef View Post
how does changing between a street pad and a track pad wear on the rotors? is it possible that one of the two will embed differently and cause some shudder, vibration, or uneven wear?

also, in the original post, the rotors on the m3 and the rotors on the corvette appear to be a little different. the m3's design doesn't have the hat cutouts (or maybe its the rotor?). but it says the m3 kit will look exactly like the vette kit. any clarification on this?
Managing pads and discs when switching between street and race friction is an important aspect of any brake system. Please check out my video on the topic, Swapping Between Street and Race Pads.

Our hat designs vary depending on platform, cooling needs, etc. If you look at the pics of the hats on our website, those are the production hats that ship in the kit.
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      12-05-2014, 10:45 AM   #187
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Some sweet pics of the Yost M3 as it preps for 25 Hrs.


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      12-05-2014, 11:16 AM   #188
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Here's another great review of our brake kit from a One Lap of America winner after a few days at VIR. In this case, the kit actually went on a rare, 420hp, 1M Coupe...pretty cool! He used our standard E92 M3 kit, which comes from the factory with the same brakes as the 1M.


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      01-08-2015, 08:05 AM   #189
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We just received some awesome feedback from one of the drivers of the Yost M3, which recently completed the 25 Hours of Thunderhill. His comments give you a pretty good idea of the durability and performance of our kit under grueling wheel-to-wheel race conditions. They started the race on a used set of AP Racing discs, ran them over 1500 miles during the full 25 hours without a disc change.

Quote:
Just wanted to get you some quick feedback on the brake kit. Long story short, we were completely blown away at how well they worked for us. We asked a lot from them and they delivered well beyond our expectations in every way. We ran them for the full 25 Hours of Thunderhill without a single issue, even without brake ducting. Being our first race with this kit we expected to have to change rotors once and pads twice during the course of the race. We started on the used set of rotors that we used for testing before the race and saved our new set for the rotor change during the race. We kept inspecting the rotors throughout the race and are extremely pleased to report that they never had to be changed and we ran all of our testing prior to the race, practice, qualifying, and the full 25 hour race on the same set of rotors. Simply amazing. As for the pads, we started the race on a brand new set and realistically probably could have made the entire race on one full set of pads as well, but they would have been close. We changed all the pads a little over halfway through the race to be safe and the pads we took out had about 14 hours on them and had probably still about 40-45% left.

We were completely shocked at how well they were holding up and we can only attribute that to the performance of the kit. Even without brake ducting the temps stayed in the optimal range for wear and performance. And the performance was out of this world. Brake torque, pedal feel, everything was spot on. They lasted so much longer than expected because we simply didn't need to stand on the brakes every corner to get the car to slow. The pedal feel remained consistent the entire 25 hours as well. You guys have really created the ultimate set of brakes and if these don't sell out immediately I don't know what else to tell you. One thing's for sure, we will never be switching away from AP. Thanks again for your support and we are incredibly proud to be able to test this kit and get back to you with such positive notes! Here's to 2015!
You can read more about their race results and the car at Yost Autosport. They're planning to have the full story and video up within a few days.

Also, here are a couple of cool renderings of the Yost M3 that a fan created in Forza 5 on XBox One...amazing amount of detail, and pretty darn believable!





Here's a profile of the real car for comparison...
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      01-08-2015, 08:59 AM   #190
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More good news...One of our customers drove his Essex/AP Racing-equipped M3 to a GT Class time attack victory at Sepang over the weekend. He put his car through 100 laps of abuse at the famous Formula 1 circuit while securing the win. Sepang is a 3.4 mile track with 15 turns and 2 long, high speed straights that end in notoriously demanding brake zones.




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      01-08-2015, 04:07 PM   #191
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Group Buy?!?!?!
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      01-26-2015, 02:36 PM   #192
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Do you sell your caliper brackets and disc hubs separately?
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      01-27-2015, 07:02 AM   #193
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Quote:
Originally Posted by bdaddylo View Post
Group Buy?!?!?!
We sell wholesale, so we don't offer group buys or discounts to retail customers.

Quote:
Do you sell your caliper brackets and disc hubs separately?
No. We only sell complete kits.
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      04-13-2015, 02:15 PM   #194
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Did the tax man help you or hurt you this year? If he hooked it up, please keep reading!

For the first time ever, we're offering a $400 off sale on our front E92 M3 BBK.

It likely won't happen again any time soon, so get 'em while the gettin's good! Thanks.
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      04-16-2015, 04:05 PM   #195
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This is awesome.
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      05-14-2015, 09:37 AM   #196
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Just an FYI gents...our development on the e92 platform soldiers on. Please see this post for details. The AP Racing Radi-CAL cometh!

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      05-15-2015, 06:32 AM   #197
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If I was doing this all over with what I know now, I would have installed AP instead of Stoptech.
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      05-16-2015, 05:50 PM   #198
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Quote:
Originally Posted by surlynkid View Post
If I was doing this all over with what I know now, I would have installed AP instead of Stoptech.
I've pretty much come to the same conclusion for when it's (almost) time to go BBK but would be curious to hear your thoughts on the matter.
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