AP Racing by Essex Brakes for the 2022 GR86

[JRitt]

Originally Posted by zeroomega

I think I need a bit clarification on this as well. I would like to know except for the mounting bracket, what other parts are changed and incompatible in the gen2 kits. I have the endurace kit for the gen 1 FR-S. Purchased from CSG but the package was actually shipped directly from Essex AP Racing. I am anticipated to get a GR86 this year and will carry over my current ap endurance kit. I don't want to be in a situation that I have to sell my used kit and then purchase a new 2nd gen kit given the fact that they are the same calipers same rotor sizes and have almost identical geometry. It's a waste of money.

I also noticed that the replacement rotors rings listed on AP's own web pages have some conflicting information. In page https://www.essexparts.com/essex-des...t-cp8350325brz, the "Whats in the box section" said "One pair 325x32mm AP Racing CP3908, 70 vane, J Hook racing discs, with fully floating 6061 hard anodized aluminum hats, and attachment hardware". However, in the technical spec tab, the rotor listed are "CP3870-138/139GC". The CP3870 are $80 more expensive than CP3908 while both rotor rings are the same 325x32mm 70 vanes design. Are they compatible? Why this conflicting information exist?

We have not measured the new GR86 yet. Our understanding at this point is that unlike the new BRZ, the GR86 uses the old suspension spindle which is identical to the Gen.1 cars. IF the GR86 spindle is identical to the FR-S spindle, your Endurance Kit from your old car will bolt on to the new car with no issues.

Thanks for pointing out the discrepancy on our site. The CP3870 discs have superseded the older CP3908 discs. They were redesigned and cast at a different foundry, and our costs on the new discs went up considerably (just like our costs on everything else over the past two years). These two iron disc rings are interchangeable on the same disc hats.

We have been working through the process of getting any and all info related to these discs updated on our site. We have about 150 applications of BBK now, and as one can imagine it is quite a bit of legwork getting all mentions updated. Thanks for pointing this one out!

[JRitt]

Originally Posted by driveside79

Any word/ETA on getting a GR86 in your shop to measure? Wish I was closer to you otherwise I would totally volunteer my car.

We have the 2022 BRZ coming back in to our HQ in two days for final test fit of the new 299mm (Sprint) Kit. Once we verify that our prototype parts fit, they will immediately go into production. Then it will be about 8 weeks until we can deliver them. We will be accepting orders in the meantime, and the 325mm kit is already available for purchase now.

[zeroomega]

Originally Posted by JRitt

We have not measured the new GR86 yet. Our understanding at this point is that unlike the new BRZ, the GR86 uses the old suspension spindle which is identical to the Gen.1 cars. IF the GR86 spindle is identical to the FR-S spindle, your Endurance Kit from your old car will bolt on to the new car with no issues.

Thanks for pointing out the discrepancy on our site. The CP3870 discs have superseded the older CP3908 discs. They were redesigned and cast at a different foundry, and our costs on the new discs went up considerably (just like our costs on everything else over the past two years). These two iron disc rings are interchangeable on the same disc hats.

We have been working through the process of getting any and all info related to these discs updated on our site. We have about 150 applications of BBK now, and as one can imagine it is quite a bit of legwork getting all mentions updated. Thanks for pointing this one out!

Thanks for the clarification but I think you didn't answer the first question. I would like to know for new sprint and endurance kit for 2022 BRZ, what have changed compared to the original 1st gen FR-S/BRZ kit? We all know the 2022 BRZ kit has a new mounting bracket, but is that all?

Thanks for the clarification on the discs. I am glad I stock up a set of CP3908 rings before they disappeared from your shop. It should cover me another 1.5 years of track days.

[JRitt]

Originally Posted by zeroomega

Thanks for the clarification but I think you didn't answer the first question. I would like to know for new sprint and endurance kit for 2022 BRZ, what have changed compared to the original 1st gen FR-S/BRZ kit? We all know the 2022 BRZ kit has a new mounting bracket, but is that all?

Thanks for the clarification on the discs. I am glad I stock up a set of CP3908 rings before they disappeared from your shop. It should cover me another 1.5 years of track days.

Sorry, I thought I did answer that. Both the caliper bracket and the discs are different. On the endurance kit we are dropping the brake duct provision and will no longer offer that.

[timurrrr]

Originally Posted by JRitt

If just the bracket is changed, our Gen.1 disc makes contact with the [2022 BRZ] suspension components.

Wow!
Thanks for the info.

[zeroomega]

Originally Posted by JRitt

Both the bracket and the disc hat have changed. If just the bracket is changed, our Gen.1 disc makes contact with the suspension components. It unfortunately just won't work. As such, it is a new kit that requires different components. We have the '22 BRZ coming in this Thursday finalize fitment with the new prototype parts.

Do you mean the old disc rubs the new BRZ's ball joint?

[JRitt]

Originally Posted by zeroomega

Do you mean the old disc rubs the new BRZ's ball joint?

I honestly don't have all the details yet, as I wasn't personally under the car. My engineering director may have even been talking about a different kit/platform. We had a meeting last week on about a dozen different new products we are in the midst of launching, and it's hard to keep track of the details on all of them. It may just be that our new bracket had to be relocated slightly laterally, so we had to reposition the disc laterally to keep it centered in the caliper. Regardless of the root cause, I am 100% positive that our new kit includes a new bracket and a new disc hat, both of which are different designs than our Gen.1 components.



As noted above, our test car will be here Thursday and I'll try to get some pics and all the specifics when the prototype parts are bolted up. I'm trying to feed everyone info real-time on this product development/prototyping process, but sometimes that means not getting the full picture until the dust settles a bit. I tend to lean towards offering more info earlier in the process vs. waiting until everything is done and buttoned up, because it gives our customers a peek behind the curtain that they don't always get. Also please keep in mind that this forum and this application are just one of many on which we are actively engaged. Thanks to everyone for your patience. The good news is that we're on the home stretch on our 299mm kit.

[JRitt]

Our prototype test fitment is complete. Our 299mm Kit clears the OEM 18" wheels with 4-5mm clearance to spare, so no issues there. The parts will go into production and we should start delivering kits in 8-10 weeks. Again, if you're in a hurry our 325mm and other kits are available now.





I also got more details from engineering on the new bracket and disc hat situation. As noted previously, the new aluminum spindle on the '22 BRZ mandated that we needed a new caliper bracket. When the new bracket was designed using finite element analysis (FEA), it was determined that the offset must be changed slightly vs. our Gen.1 design to maintain the strength of the part while accommodating the new spindle. If we had kept the same offset while trying to mate to the brackets to the new spindles, we would have had to thin the brackets out too much in critical areas to maintain proper strength. Since the caliper bracket offset was changed, the offset on the discs also had to be changed for them to be centered properly in the calipers.


If you look at the pic below, you can see the issue. The humps on our Gen.1 bracket were preventing it from sitting down far enough on the spindle for the mounting holes to line up. If we removed those humps on the bracket and left it on the same plane, that area of the bracket would have been thinned out too far to maintain proper strength. Instead, we shifted the bracket far enough laterally to the point where we could maintain some beefiness to the part. This is reason number 7,356 why you want parts that were designed by experienced pros, and not by some guy in his mom's basement! We take these things very seriously and don't just hack and slap parts on cars because someone on the internet told us they should fit.


Again though, all of this may be irrelevant to the GR86, since all of our sources tell us the spindle is identical to the Gen.1 cars...which would mean our original designs fit the new GR86. We won't know that for sure until we get a car. If you know of anyone who can loan us their GR86 in Charlotte, NC, please let us know and we will confirm fitment. Thanks!

[Jianlun]

JRitt, I am.planning on getting this new slightly offset 299 Sprint kit, but to place it on my incoming GR86. Because months into the future, I would want to change my front hub carriers to the 2022 BRZ alu ones (and I believe many other will be thinking the same). So it's more future proof.

May I ask if there are any drawback to using these new slightly offset brackets/disc hats on the new GR86 even though it does not "need" this offset? And I guess by extension, any drawbacks to putting them to the gen 1 brz/gt86/ft86?

[zeroomega]

Originally Posted by Jianlun

JRitt, I am.planning on getting this new slightly offset 299 Sprint kit, but to place it on my incoming GR86. Because months into the future, I would want to change my front hub carriers to the 2022 BRZ alu ones (and I believe many other will be thinking the same). So it's more future proof.

May I ask if there are any drawback to using these new slightly offset brackets/disc hats on the new GR86 even though it does not "need" this offset? And I guess by extension, any drawbacks to putting them to the gen 1 brz/gt86/ft86?

I think the front track width will increased by 1-2mm, like placing a very thin wheel spacer. The scrub radius will be changes slightly due to this but I think the change of the feeling will be negligible.

I plan to get a GR86 but I am not anticipating to get the aluminum BRZ knuckles. The weight saving is very small compared to the weight saving from BBK and aftermarket wheels.

[JRitt]

Originally Posted by Jianlun

JRitt, I am.planning on getting this new slightly offset 299 Sprint kit, but to place it on my incoming GR86. Because months into the future, I would want to change my front hub carriers to the 2022 BRZ alu ones (and I believe many other will be thinking the same). So it's more future proof.

May I ask if there are any drawback to using these new slightly offset brackets/disc hats on the new GR86 even though it does not "need" this offset? And I guess by extension, any drawbacks to putting them to the gen 1 brz/gt86/ft86?

We haven't seen the GR86 yet, so no guarantees that our kit with the Subaru aluminum spindle will work on that car. I can't imagine why that wouldn't work though.



We also have not yet gone back and looked to see whether our new kits will fit on the Gen. 1 cars, but that is something we plan to do. That would make our Radi-CAL applications available for Gen.1.



In other words, I would expect all our new kits will bolt up on a GR86 using the new Subaru aluminum spindles or any of the Gen.1 cars without any issues. Again though, we just haven't gotten there yet on verification.

[Jianlun]

Thanks for the quick reply and looking forward to your confirmation. I guess if they fit, the only effect is a very slight scrub radius change as described by zeroomega? Any chance you can find out the scrub radius and which it changes from and to? You know, the old turn your wheels on a powered floor and see the circular marks trick.

[JRitt]

Originally Posted by Jianlun

Thanks for the quick reply and looking forward to your confirmation. I guess if they fit, the only effect is a very slight scrub radius change as described by zeroomega? Any chance you can find out the scrub radius and which it changes from and to? You know, the old turn your wheels on a powered floor and see the circular marks trick.

A generous GR86 owner will be bringing his new car to our HQ at the end of this week most likely. We will update when we know what the situation is.

[timurrrr]

Originally Posted by zeroomega

I think the front track width will increased by 1-2mm, like placing a very thin wheel spacer. The scrub radius will be changes slightly due to this but I think the change of the feeling will be negligible.

What makes you think the track width / scrub radius changes?

Originally Posted by JRitt

When the new bracket was designed using finite element analysis (FEA), it was determined that the offset must be changed slightly vs. our Gen.1 design to maintain the strength of the part while accommodating the new spindle. If we had kept the same offset while trying to mate to the brackets to the new spindles, we would have had to thin the brackets out too much in critical areas to maintain proper strength. Since the caliper bracket offset was changed, the offset on the discs also had to be changed for them to be centered properly in the calipers.

JRitt was talking about the offset of the brake rotor / caliper, not the wheel offset. I'm assuming the offset wasn't corrected by simply putting a spacer under the rotor hat (who ever does that for purpose-built kits?) and rather a new hat is used. I'm also assuming that the thickness of the new hub part of the hat hasn't changed either.

Originally Posted by Jianlun

Thanks for the quick reply and looking forward to your confirmation. I guess if they fit, the only effect is a very slight scrub radius change as described by zeroomega? Any chance you can find out the scrub radius and which it changes from and to?

Even if the scrub radius did change by a couple of mm, you won't notice.
Definitely less change than what you'd get by putting wider wheels for track-oriented tires.