02impactblue

I need to upgrade the brakes on my c5 z06 track car and have narrowed it down to the 2 kits mentioned. I believe both kits will serve me well, so the deciding factor will be running costs. I think the pads are cheaper and slightly thicker on the AP kit, so advantage AP. The next concern would be rotors. I have heard great reviews on the stoptech rotors lasting an entire DE season of 10-15 weekends. I like the fact that the T1 AP kit can use a stock rotor in a pinch but does anyone have any info on the 12.8" J hook rotor life? I think the cost on replacement rotor rings between AP and stoptech are comparable. I can use my 17" wheels with the AP kit, so tires would be cheaper..advantage AP. Any recommendations from anyone actually using these brake kits?

UstaB-GS549

The stock 17" Z06 wheels will clear, but OEM Grand Sport 17x9.5 fronts will not.

argonaut

I thus far have 10 track days on the AP rotors and they look really good, slight heat checking but no cracks at all. I'm amazed, I use to crack "napa" type rotors with regularity.

I was in the same position as you last summer and decided on the AP kit primarily because it fits under my 17" fronts. I've been exceptionally happy with the decision.

Joy of 6

Got my vote also.
The bigger pads will absorb more heat and keep the braking very consistent all day long!!

JRitt@essex

02impactblue,
I'm uniquely qualified to answer this question...I was the sales mgr. at StopTech from 2003-2008, and I now work for Essex (the importer and distributor for the components used in the AP T1 kit). I worked with the AP folks and Gary at Hardbar to spec the T1 kit. Here's the breakdown as I see it.

Calipers
Anti-knockback springs
AP Racing has them, StopTech doesn't. People severely underestimate how valuable these springs are. After going through S turns, you'll have a much lower pucker factor in the next brake zone with the springs installed.

Piston type
StopTech= cast aluminum
AP= machined stainless steel
Stainless is far superior at keeping heat out of your brake fluid

Weight
ST-40 weighs 7.94 lbs. without pads
AP Racing CP8350 weighs 4.8 lbs. without pads...roughly half of the StopTech's

Dust Boots
StopTech is a street caliper, and as such uses dust boots. CP8350 has none. If you've ever run dust boots on the track, you'll find that they burn up and cause a big mess almost instantly. Their only value is if you're driving on winter or debris/dirty roads. As soon as they go on track they essentially lose all value.

Seals
Both calipers have quality, high temp seals.

Hydraulic protection
ST-40 has none, while the CP8350 has it for both bleed screw and crossover tube. This feature protects the hydraulics from track debris, and when you're swapping wheels.

High quality forged aluminum
The caliper bodies on the ST-40 and CP8350 are both high quality forged aluminum parts.

Pad choice/cost/size
Both calipers have tons of pad options. The pad surface area on the ST-40 is slightly larger, but they are a few mm thinner than the pads used in the CP8350. Overall pad mass is very comparable, but the nod goes to the thicker pads in terms of wear rate. On average, pads for the AP caliper are $100 less per set for the same compound.

Stainless Steel hardware
Both calipers have good stainless steel hardware.

Footprint/size
In addition to weighing much less, the CP8350 has a substantially smaller footprint and offers superior wheel fitment.

Finish
StopTech= painted. Look pretty, but will not look as good after hard use. Paint and powdercoat tends to change color dramatically at track temps. If you're driving through road salt, they will be better protected than anodized.
AP Racing= anodized. Look 'racier' (like what you see on full-blown race cars like C6R) and do not color shift nearly as much.

Rebuild Service
Essex offers a lifetime professional reconditioning service. For a $125/caliper you can send your calipers to Essex and have them rebuilt by the same techs who service NASCAR and ALMS teams. StopTech can rebuild, but I'm not sure how formalized their procedures, policies, and prices are at this time.

Discs

Quality and Price
Both companies offer high quality discs for the kits in question, at very similar prices. The AP's are actually a bit cheaper for replacement iron ($249) vs. $275 (i think it's still this much) for the StopTech's. Discs from both manufacturers are quality castings that are crack resistant and will last a long time under heavy track use. Due to the enormous number of variables, it's tough to say one would give you more longevity than the other. There are plenty of users of both on this forum who are getting the type of wear rates you describe.

The fact that the AP's are able to get similar wear, even though they are over an inch smaller (12.8" vs. 14.0") is notable however. Their 70 vane internal construction, and patented J hook face slot are the #1 choice at the elite level of motorsports (NASCAR, ALMS, DTM, Super GT, etc.). That said, there are plenty of World Challenge and Grand Am teams running StopTech discs with great success.

Disc hats
Both have a quality design and are made from aircraft grade aluminum. Both are optimized for weight and airflow.

Weight
I don't know the weight offhand, but I'm fairly certain the AP's will be a bit lighter.

Wheel Fitment
Wheel fitment is superior with the AP system as a whole.

Brake Lines
Both systems came with a high quality set of brake lines.

I actually ran the StopTech ST-60 system on my C5 Z06 while I worked at the company (and their ST-40 system on my 350Z). It is an excellent system with high quality parts. That said, the AP T1 kit was based with that system firmly in our sights. We tried to look at every piece of that system and produce something that eclipsed its performance, all while keeping the costs down. I believe we have succeeded...more technology, higher specification, lower running costs, etc.

Rednels

Wow, good info.....

John Shiels

I would go AP!

02impactblue

thanks for the detailed comparison JRitt

BERETTA

Thanks for taking the time to show us the comparison, great info

dvandentop

thanks for the in depth comparison

JRitt@essex

No problem gents, thanks for the continued support.

I ran some more specific price comparisons on popular race pad replacements. These are either prices we offer, or that I found with a quick web search for the brand we don't sell (PFC). I looked at the same pad compound for both the StopTech ST-40 and the AP Racing CP8350:

CL Brakes RC6
ST-40= $300.53
CP8350= $192.00
Difference= $108.53 per pad set

Hawk DTC-70
ST-40= $249.00
CP8350= $154.79
Difference= $94.21 per pad set

Ferodo DS1.11
ST-40= $421.83
CP8350= $210.92
Difference= $210.91 per pad set

Ferodo DS2500
ST-40= $215.12
CP8350= $125.08
Difference= $90.04 per pad set

PFC 01
ST-40= $326.00
CP8350= $172.93
Difference= $153.07 per pad set

The average cost difference across those five pad compounds comes out to $131.35 per pad set. Using the numbers above in an example...If you run through 4 pad sets of DTC70's in a season (conservative estimate), you'd spend $996 with the ST-40's, but only $619 with the AP's. That's enough for couple of sets of pads for the AP calipers the following season. With something like the DS1.11's, it's a much larger difference. Four sets for the ST-40's would be $1687,32 vs. $843.68, a difference of $843.64. That would go a long way towards an extra set of tires for the season, or would cover the entry fee for multiple events.

TGiuliante

Is anyone running AP on a c6Z?

Rob Willis

I have a set on my 2011 GS.

TGiuliante

how do they hold up at the end of your sessions

fatbillybob

Actually stoptech makes an SCCA T1 kit with 4 calipers using the st40 front and st41 rear caliper set for the c5 and c6.

ST has these an an option for the race kit. When a caliper flexes the knockback is a problem and springs solve that. That's why we have the huge pad taper with the oem calipers. The ST40 is one of ST's generic calipers and it is beefy and does not flex on our cars. I have amazingly zero tad taper. Well...there has to be some I'd have to get the micrometer out. I don't think the ST's need the springs.


less weight is less unsprung weight = good. I do not know the st40/41 weight but they look big. Big is a big heat sink. I think that reduces caliper flex, and reduces heat transfer and build-up so pistons can be aluminim. I'm pretty sure on the race kit the pistons are SS or an option. I have never pulled the pads to see.


there are no dust seals on the ST race kit


The st bleeders are right out in the open but the position is such that you would need a pretty direct hit to break them off. That would mean just screwing another bleeder in. Not sure that is a big deal unless that happened in an enduro. I wonder if people have to bleed a caliper during an enduro? Does the recess in the AP make it more difficult and cost time to get a wrench and bleed tube in there? I also bleed brakes with my wheels on through the wheel spokes. I'm too lazy to take the wheels off. The ST has nice easy access.

My set of pfcs were 400 bucks for all four corners. I like the thick pads but I have been surprised at how long my thinner pads have lasted. Maybe it is because of a surface area thing. Interesting thing about a big flat pad like the ST's is that my brake pedal height remains very constant all through the wear range right down near the backing. This means a very consistant pedal feel all through pad life and easier consistant heal toe position for a track hack like me.



I'm not sure superior fitment. I've been in many T1 discussions on wheels. Both offer terrible choices that are economical. We racers use about 3 sets of wheels. So far the only wheesl to fit that are 17" without spacers are the 949 wheels that Oli uses. Most have given up and gone to 18" wheels but even there only the forgestar wheel is of the proper offset for the BBK's. There are other 18" wheels that fit with small spacers. The cheapest option is the 18" C5Z rear on the front. I don't think either caliper has a win on fitment. Other popular BBK's are the brembos and willwoods and I think each is different and the wheels guys are probably confused and have really not supported the idea of making us some wheels. Even CCW JohnP who supplied most of us the race wheels on the old oem brakes has just kinda thrown up his hands and does not want to really get involved making us any wheels. If you go 18" there is no advantage here. Weight! that makes a difference. I have no clue what the ST weighs. One of these days I'll weight it.

The ST's come painted or anodized. Painted is cheaper. I don't think there is a performance advantage there. ST also makes the trophy caliper that is the same ST40 caliper cutout and lightened and anodized. There is no stopping advantage there but a minor weight advantage. Not sure how much I was trying to keep my costs down. ST will rebuild calipers just send them in or they will sell you the rebuild kits and you can diy and save some money.



I don't know about weight either. the ST T1 kit is 14" front and 12.8" rear. iirc that's 355x328mm. Those dimensions are the T1 racing max sizes 5% over Z51 sizes. I don't know the cost never replaced the rings. The T1 kit uses the "trophy" rotor not the aero rotor on the street kits. The trophy is for racing and is full floating. It comes with 010" of play but you can get other levels of float too.


I agree with the essence of JRitt. A lot of thought went into the AP's. The AP's certainly appear to have a different approach to braking the car. It is a great looking system and is winning races in T1. You can't take anything away from it. The ST T1 kit was developed after the AP kit but because of ST's size I think they have more instantly available product. That is how I got involved with ST. As it was explained to me ST thought the oem rear caliper was holding the chassis back. They thought they could optimize braking more than their front axle kit by upping the rear caliper yet retain the stock master cylinder per the T1 race rules. There is no question the current AP is less cost than the ST system. But the ST is four calipers/rotors etc.. The ST race kit does not have a front axle only option as far as I know. It was designed as a 4 caliper system and it is more costly but they thought that's what it takes to get the best braking they could deliver. Going fast always costs money. I have been very happy with the ST's and glad to rid my car of the OEM boat anchors.

I hope my comments are taken as informational and not confrontational. I respect both systems.

sebdavid

I thought at least the AP system and the LG Wilwood Gstop Wilwood kit both allowed use of the stock 17" Z06 wheels?

Speaking of the LG system, I'm curious why the OP eliminated it from his purchase process. Looks to be a pretty good kit as well and Wilwood is a well-respected name, no?

DOUG @ ECS

Great comparisons guys.

I personally have StopTechs, but I have not raced on track with the AP's so I have no comparison other then I am very happy with the Stop Techs in both wear and performance.

Good luck with your choice!

trackboss

I've dealt with stoptech for many years. They originally sponsored my old AI race car. I currently have their setup on my C5. I recently chose to rebuild the calipers and added the springs. I have not really driven the car much, but IMO they are a bit stiff. I've installed springs in other calipers, similar to the AP stock car style ones above, and the springs were much lighter and worked very well. I like the fact that the AP's have a boss for the spring to register on the piston.
I'd have to say stoptech are excellent brakes. The only thing I absolutely hate about them is the coating. They are anodized then powdercoated. Powdercoating calipers is something I'd consider stupid. Of course I see the retards all the time with nearly 10k worth of brakes simply for show so I suppose it does help sell brakes to so many that will never need them. It is not meant to tolerate heat well and discolors after use. Not to mention just plain wears easily. Especially when trying to clean the calipers of brake dust. Brake cleaner removes the finish.

argonaut

Gary's AP T1 does fit under the 17" Z06 speedlines and alcoas with plenty of room to spare. That's one of the primary reasons why I bought them.

drivinhard

Just a note on the wheel fitting thing (for folks looking in that maybe want to purchase either). Do not confuse wheel diameter clearance, with caliper to wheel spoke clearance. You can have 1 of the 2, and still not have them "fit". Most of the 13 and 12.8" kits will fit under the 17" dia, in terms of the caliper fitting inside the barrel of the wheel. Most of the fitment issues with these bigger caliper kits are the caliper to spoke clearance, which is almost all dependent on the caliper and wheel combo but has really nothing to do with the dia of the wheel.

This isn't directed to anybody in particular, as I've heard guys P&M about it a the track plenty enough, is about "X" brakes not fitting under the CCW classics. Well duh, it's the wheel design, they have terrible spoke clearance (for any caliper). Once you hang 2 or 3 pistons on the OUTSIDE of the caliper, and stick a 20mm pad in there, it HAS to come off the face of the rotor a lot farther, period. Any fixed multi pot caliper is like that, this is not a brand A or brand B problem. It's a terrible wheel for caliper/spoke clearance, and it's noticeable the second you lay eyes on them, even without a wide 4/6 pot caliper behind them!