Brake Project and Interest: AP Racing CP9668/9660 Kit
 

Price breakdown:
10/19/22

Calipers: $2100
Brackets, lines, bolts and hats: $850
Rings: $900
Bobbins: $125
Total: $4075

I've spent way too much time researching brake kits for my Z and not being fully happy with any of them and have decided to work with a shop to manufacture bracket and hat adapters for the AP Racing 9668 calipers for the 370Z with 370x34 or 36 mm rotors with 72 vanes. Hardware made with 6061 or 7075 aluminum.

Would anyone be interested in this? It would help reduce my manufacturing costs and my goal is to be competitive with the Stoptech trophy kit on pricing while offering better cooling.

ADVANTAGES OVER THE TROPHY KIT:

• Lighter caliper by 1.5 to 2 lbs vs Trophy kit.
• Thicker pad (25mm) that can provider much more life for just a tiny bit more cost per set
• Stainless steel pistons vs aluminum on the Trophy kit (upgraded pistons cost $1200 from Stoptech)
• Higher 72 vane count (dissipate more heat)
• Wider air gap in rotors (pump more air)
• 370mm rotor maintains compatibility with most 18 inch wheels
• Similar rotor replacement cost for better heat dissipation
• Can switch between 9660 and 9668 with the same hardware to save on upfront cost.

ADVANTAGES OVER THE WILWOOD AERO6 KIT:

• Still lighter than the Aero6
• Thicker pad by 5mm
• Larger, better flowing rotors
• Much easier pad changes
• I assume stiffer caliper (for sure much stiffer than the Forged Narrow Superlite)

ADVANTAGES OVER THE (NONEXISTENT) ESSEX AP RACING KIT:

• Will actually exist (Essex has been stringing me on over 2 years on this and won't just take my money)
• Almost certainly cheaper
• Rotor replacements will for sure be cheaper
• Potentially better cooling rotors (by a bit, not by much)

CONS:

• Due to how damn expensive these calipers are, you'd have to source them separately, but I'm looking through suppliers who can keep costs below $1300 per caliper. $1000/ea if going 9660.
• Calipers have fixed piston sizes, not as many options like Stoptech does, so you'll need pad stagger, such as XP12/XP10 front/rear.

ESTIMATES:
Around $1500 give or take 250. This should cover the hats, rotor rings, bracket, all hardware.
Doesn't include pads, since people have large differences in preference.
Timelines are likely 2 to 3 months out between my initial designs, 1-2 revisions, several test days, and finalized hardware run.

GOALS:
I will be testing these myself first. I mainly test at Blackhawk Farms Raceway, which is very hard on brakes.

On the rotor side, my goal is to lower my rotor temps by at least 50F over my current wilwood 72 vane setup, which already lowered by 100-150F over my Z1 2-piece setup, which at the time, already lowered by around 100F over stock. So vs stock I'd estimate 200-300F lower rotor temps. This should be reasonable because these are wider, larger, and have a better vane design. They must also come in lighter than my custom Wilwood setup, much lighter than stock.
On the caliper side, my goal is to at least double my pad life, via thicker pad AND cooler temps. It must come in lighter than the stock Akebonos including bracket.
I figure people on the forums would be interested in the progress on this.

Current state:
All crucial dimensions taken for OEM brakes
Handful of shops identified for rotors and CNC work

Next steps:
I need to get a pair of 9668's.
Mock up bracket to test against current 355 rotor setup to validate offsets
Finalize dimensions
Decide on rotor ring
Model brackets and hats

7/8/21 Update:

• Calipers sourced, pending payment.
• Bracket and hats initial designs submitted to first shop, and paid for.
• Rotor rings finalized and ordered, pending shipping (may take a while).
• Caliper bolts ordered.

What's left:

• Finding reliable supplier for bobbins and hardware kit (may need to be from the UK directly)
• Finding reputable brake line source. I believe our calipers use M10x1.0 so may not be too difficult. But may just get a longer line and skip our weird front brake line tomfoolery.

7/8/21 Evening update:

• Bobbins and hardware sourced, awaiting order confirmation
• Rings shipped!

7/9/21 Update:
All parts ordered. Now just waiting as parts come in.

7/10/21 Update:
Rings came in!

7/12/21 Update:
Brackets and hats manufactured! Will see how tolerances and initial measurements were. Fingers crossed, but will be a while before next update.

7/13/21 Update:
Oh wow, FedEx international shipping is amazing....
Calipers delivered today!

7/16/21 Update:
Hats and brackets arrived today!
Fitment test was perfect on the hats and I am feeling good on the bracket.
In the home stretch!

7/20/21 Update:
Bolts and washers came in!
Mounts right up, now just gotta grab some pads from a friend so I can test fit while I wait for my Glocs to come in!

7/31/21 Update:
GLocs came in! They are FAT. My friend's pads were worn but these, oh boy.

Pics:
https://lh3.googleusercontent.com/c9...-no?authuser=0

https://lh3.googleusercontent.com/WA...-no?authuser=0

https://lh3.googleusercontent.com/Lv...-no?authuser=0

wondering . . . why not Brembo GT?

9668 is lighter, has way thicker pads, comes at a lower price for the same quality (Brembo GT line requires the GT-S caliper to be comparable, maybe even the GT-R), and has way easier pad changes. I also find way better documentation around AP Racing calipers.

I just don't like the caliper as much. I see a lot of people on other platforms run the 9668/9660 calipers and they absolutely love them.

Some seriously thick pads with the 9668.

A nice article on 9660 vs 9668:
https://www.essexparts.com/news-blog...9660-or-cp9668

Yup! Hoping to EVENTUALLY make some of the cost back via less frequent pad changes.

Used to be able to get the AP Radical II BBK's for the Z from Stillen and a few other places in the states. Then all of a sudden. Everyone quit selling the kits. Just as I was ready to squeeze the trigger for them. :shakes head:

interested.

Did you look at Stoptech? Make sure you get the brake bias correct otherwise it will no work correctly.

:rolleyes: :rolleyes:

He literally mentions it in the 4th sentence.

LOL, I didn't see it. I checked on the Stoptech's for my car and they were dang expensive. 8k and change.

Yes, and Stoptech Trophy, even the STR calipers, have aluminum pistons.
And their rotors aren't as effective based on vane design and count.

I decided after some comments on my FB thread to use the AP racing 372x34mm discs.
Finding the bobbins are the toughest part. They really make them hard to find in the US if you aren't buying a full kit from Essex, but I have part numbers I can get from the UK.

Brake force with 9668's is 12% less vs stock calipers with the same rotor diameter. Moving to 372mm rotors makes brings it to a 7.5% reduction, easily compensated for with pad stagger. Or, once my project funds recover, new calipers for the rear.
Stoptech's kits DO keep it at 100% +/- 1% change. 92.5% is still closer to stock than Wilwood's kit, which is at 91.5%.

SAME! I'd finally convinced myself and checked they'd fit my wheels.
Been on quite the research journey since then and I'll be ending up with a better setup than the Radical street kit would've been.
We dodged a bullet there though. The rotor rings with the Radical kit are no longer available.
The ones I'm using will remain supported by AP for much longer. So many kits use this size. (Literal worst case, once I get the initial designs manufactured and tested, switching out to new disc sizes will not be too painful either. Both design wise and money wise. I don't expect this to be necessary though)
The 9668 caliper is also far more popular than their Radical street kits.

That's a lot of work done, thanks for sharing!

Nice work! The big elephant in the room is the OEM ABS system. It still sucks. I am not saying the BBK upgrade will not bring gains but because the ABS system is lacking there is still more on the table.

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Oh yeah. I believe there's braking performance to be gained shifting bias a bit rearward but am wary of it because I've heard ABS consistency gets worse, especially if rears lock first. I'll let Austin Hertel and other folks pioneer the MK60 swaps before I jump on that.
So far, my ABS doesn't get in my way.

Rotor rings ALREADY shipped out, should get here Monday. Bracketry and hats I expect a few weeks lead time. I'll just get to start at the AP rings for a few weeks while I wait on everything to get here I think.

LOL, Austin and I have been talking since he made the decision to switch his out. The shop I am using suggested I do swap as well. I got a good quote on on the swap. I also got a serious upgrade that I will share later. Dialing bias should be a significantly improved.

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Got the rings in yesterday!
Super fast shipping. Which is awesome. My Wilwood rings have had a 2 month backorder. Bodes well for the future with this kit, because I won't need to stock one set in advance like I do today.

https://photos.app.goo.gl/wh82J7jRedzeXGSv7

Good deal.

We run the Essex AP Racing radical 9660 bbk on the TT RS. It cut 26lbs of unsprung weight off the nose compared to the oem 8 piston calipers (1st gen r8 brakes).

These brakes are the bees knees, best brakes we (wifey and I) have ever had on a car.

If y’all can get this to work, you won’t be disappointed.

PS- rusty, stillen never sold the real track/race AP radical brakes, afaik, Essex parts is the exclusive North American importer/supplier for these kits. Stillen sold the street bbk AP Racing radical bbk setups. Go look at Essex parts website, you’ll immediately see the difference. They’re the real deal, but unfortunately still don’t offer a kit for the 370z. I’m hoping that’ll change for the z35. :tup:

Agreed! The shop that is doing my ABS swap uses AP for swapping ceramic brake kits on Porsches, McClaren, Ferraris and all other serious track cars.

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9668 calipers shipped out from the UK! I ordered mid Friday, so after their business hours. Pretty much next day or same business day shipping.

Super nice bonus will be that the bracket design AND pads are interchangeable between 9668 and 9660 (according to Essex, I will eventually confirm against AP's diagrams for each), so someone wanting to run the lightest setup possible can trim off 3-5 lbs using 9660 instead.

:excited::excited::excited:

Hardware manufactured! Now just waiting on calipers plus all the rest of the hardware from UK.

What are you going to do for an e-brake?

Just front kit right now.

Might try a rear rotor option later on, since our rear setup is only 20mm wide. I have a BBK from Massive Brakes who had a steel ring attached on the other side of the aluminum hat for an E brake. And some companies make the hat in the barrel shape but warn you E brake is for holding still only.

But my rear temps are 200-250F lower than my front so they are not gonna get prioritized.

My RacingBrake rear rotors have a steel ring inside the hat.

Okay, so thaaat's why shipping cost so much

Fedex pretty much overnighted these internationally.

The calipers are made SO WELL. I almost don't want to mount these, and just keep them on our coffee table to admire forever....

Agreed! LOL, I felt the same way with my Stoptech calipers and rotors. Quality products are just that, they look good and perform better!!!

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Oh the bad influence that present themselves in this forum!!!!

Hats and brackets finally came in today! (when you pay for cheap Fedex....)

Just waiting on caliper bracket bolts before I test mount them. And then pads before my next track day.

Am currently running R10 rears, with a spare set of R8. I am thinking either sticking with R12 front or trying out the endurance R14 pads and bumping down to R8 rears again.

Potentially trying out now pad compounds.

:yum:

Starting to compile pad compounds. I went ahead and ordered Gloc R12 for now to make sure I can test next month.

Out of curiosity, what else would people like to run? I can put together compound combos that I think would work well as a starting point.

Brand------Shape/Part number----Est Price
Pagid--------1539-----------------------$550
PFC----------CP3558D54----------------$350
Ferodo-----------------------------------$600
GLoc--------GPX14----------------------$350
Hawk------- HB109U.980---------------$425

Okay so as with many things one company make products for various other companies or subsidiaries. Porterfield makes brakes for Raybestos, Hawk, Pagid, Setrab, Tilton, Wildwood, Brembo, Stoptech, XRP, DEI, Motul and Redline. I only mentioned all of those because if you are NASA member you can get a 20% discount on Porterfield, Rabestos and PFC 10%, Hawk 15% and Pagid 5%. Porterfield and Rabestos are popular brands not on your list.

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Just for reference, we run ferodo dsuno’s front, ds 2500’s rear. Been very pleased with this setup, iirc, the dsuno’s have been superseded now with a newer compound. Much better setup compared to carbotech pads used on the z with oem nismo brakes. To be fair, the carbotechs were xp10/8 combo and the dsuno’s iirc are more comparable to a xp16/20.

Long story short, I’m a fan of ferodo pads. :tup:

Every Pagid pad that I've used on front or rear has chunked off into pieces. They can't take the heat (no ducting for me). (RS29, RS19, RS2-4)

I'd have to look up your model #'s for the Hawk and PFC to be sure of the compounds.. but I've had great success with those brands. DTC-60 front and PFC-01 rear respectively (they don't make the PFC-01 any longer.. unfortunately)

I'll be trying a different Ferodo this weekend (1.11 i think). The first Ferodo (ds2500) held up to the heat, but didn't perform to my liking (as a rear pad).

I've been considering switching to Ferodo in the future just from the good things I've heard on longevity from other forums too. What was lacking with the DS2500 on the rear? Too low friction, too low operating temps?

As a quick update on the kit, I'm getting caliper bolts in today, to mount the caliper to the brackets. Should be able to test fit this week! This weekend is busy, and I'm still waiting on my R12s to come in, so likely looking at the first week of August for initial street tests.

Grade 12.9 hardware in! I remembered a friend from autocross also runs 9668s at the track and turns out he has spare pads, so I'll be able to run a test fitment this week. Even before the GLOCs come in.

https://lh3.googleusercontent.com/Yl...-no?authuser=0

Once the pads were warmed up, the friction was too low. Bias shifted to my fronts and was getting lockups in the front (DTC-60s, Dunlop Star Spec III tires). So, I could have adjusted more bias to my fronts (I removed ABS and have a proportioning valve to adjust rear bias).. but I feel like I'm already putting a lot of load on the front.. so I'm trying a different Ferodo compound on the rear. The DS2500's withstood the heat fine.. ie. they didn't crack apart like the Pagids.

Everyone's situation is going to probably be a little different. You may have to try out some different things to match what works for you and your setup.

https://www.ferodoracing.com/product...e-pads/ds2500/

Test mounted!
Perfect radial offset. The shop mixed up translating a dimension, so I'm getting another set of brackets. made.

There's over a CM gap with my Titan TS5 wheels in 18'" diameter, so room to upgrade to 380 or even 390mm rotors in the future if absolutely necessary (shouldn't be, I have a friend running these with his Camaro SS in 372mm and C6 Z06 in 355mm without temp issues).

Anyone interested in getting this kit, post to let me know! I can get these made in 6061 or 7075 aluminum.

https://lh3.googleusercontent.com/pw...-no?authuser=0


https://lh3.googleusercontent.com/pw...-no?authuser=0

Pricing?