Hi Guys,
I've now had 3-4 forum members message me over the past couple of weeks asking about a direct comparison to the StopTech systems currently on the market. I really appreciate that people don't want to start a mud-slinging brand vs. brand battle in my thread. That said, I'm happy to lay out the facts to those who are interested. I think it's important for people to understand what exactly they're getting when spending thousands of dollars on a brake kit. I don't see any harm in sticking to the facts/specs, and I'll try to leave out conjecture.
I was actually the sales manager at StopTech for roughly five years before taking on my current role at Essex/AP Racing. While at ST I was also involved in just about every part of the process of bringing their products to the market (production, product mgmt., component sourcing, etc.). I doubt there is anyone more uniquely qualified to compare their system to ours. Below is a comparison of the components in our kit vs. those in the StopTech setups, but this info also applies in the same manner to other high performance street big brake kits (painted calipers, aluminum pistons, dust boots, drilled discs, etc.) currently on the market.
Here's the breakdown as I see it comparing our
Essex Designed AP Racing Competition Big Brake Kit vs. the StopTech six piston BBK with 15" (380x32mm) discs.
Calipers
Essex version of the AP Racing CP5060 six piston vs. StopTech ST-60 six piston
Anti-knockback springs
AP Racing has them, StopTech does not. 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 AKB springs installed.
Piston type
StopTech= cast aluminum
AP= machined stainless steel, domed back, ventilated
Stainless steel is far superior at keeping heat out of your brake fluid vs. aluminum. The domed back on the AP pistons adds substantial stiffness, which can be felt as a firmer pedal. The ventilation on the piston edges allows for more cooling air circulation. All of these features add up to greater heat rejection around the piston area, ultimately leading to a lower chance of brake fluid boiling and resulting fade.
Weight
StopTech ST-60 is 8.9 lbs.
Our version of the AP Racing CP5060 weighs 6.2 lbs. without pads...approximately 3 lbs. lighter per side than the StopTech ST-60.
Dust Boots
StopTech is a street caliper, and as such uses dust boots. The AP CP5060 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 temperature seals.
Pad choice/cost/size
The ST-60 and AP Racing CP5060 use the same basic shape (it was originally an AP Racing shape, implemented many years ago. The D54 radial depth version we use in the CP5060 has an additional 3 mm of surface area along the lower edge, giving a bit more pad volume vs. the D51 pads in the ST-60. Pricing on the two pad shapes is the same.
Stainless Steel hardware
Both calipers have quality stainless steel hardware.
Footprint/size
In addition to weighing much less, the CP5060 has a smaller footprint and tends to offer superior wheel fitment.
Finish
StopTech= painted. Look pretty, but will not look as good after hard use. Red turns maroon/brown, etc. Paint and powdercoat tend to color shift dramatically at track temps. If you're driving through road salt however, they will be better protected than anodized.
AP Racing= anodized. Look 'racier' (like what you see on full-blown race cars like the factory M3 racers) and do not color shift nearly as much. I tell people that they go from grey to ugly grey.
Bracket
Both have high quality anodized aluminum brackets and aircraft quality hardware.
Rebuild Service
Essex offers a lifetime professional reconditioning service. For a $150/caliper you can send your calipers to Essex and have them rebuilt by the same techs who service calipers for NASCAR Sprint Cup and ALMS teams. StopTech can rebuild I believe, but I'm not sure how formalized their procedures, policies, and prices are at this time.
Discs
Design
Discs from both manufacturers are quality castings that are crack resistant and will last a long time under heavy track use. That said, the AP Racing discs are a heavy duty 72 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.). The StopTech's are only a 48 vane disc with a conventional slot pattern.
Disc hats
Both have a quality design and are made from high grade, anodized aluminum. Both are optimized for weight and airflow.
Weight
Essex/AP Racing hat/disc=17.6 lbs.
StopTech hat/disc= 21-22 lbs.
When you combine the caliper and disc weights, our system weighs 9-10 lbs. less per side vs. StopTech or 20 more lbs. off the nose of the car.
Disc Size
Each customer will have to decide if they want to go with a 15" or 14" disc. I addressed the 'size issue' earlier in this thread. I believe a smaller diameter AP Racing disc can outperform most larger discs from other manufacturers. A 380mm disc does offer more thermal mass, but design is just as important as size.
Spare Disc Price
Even though the AP discs offer far more features, pricing is almost the same as StopTech's recently increased price per disc. Replacement iron prices per disc are as follows:
$359 Essex/AP Racing Sprint Kit (355x32mm)
$360 for the StopTech 380x32
Other Items
Wheel Fitment
Our Essex Comp kits sit inboard of the StopTech setup a bit, offering superior clearance. I'd need to check to find the specific difference. Obviously with a smaller diameter disc, our kit will fit many/most 18" wheels, whereas the StopTech kit will not.
Brake Lines
Both systems came with a high quality set of brake lines. The Spiegler lines in our setup use all stainless steel fittings made in Switzerland (assembled and tested in Ohio). The fittings on the ST lines are not quite to the same spec.
StopTech Trophy Kit
The other option to go with for a StopTech six piston on a 15" disc would be their Trophy system. The differences in that system vs. their standard setup are: Caliper weighs about a pound less than the standard ST-60 roughly 7.9 lbs...it has more material removed during the machining process, caliper is anodized, available with no dust boots, washers can be flipped on discs to offer more float, disc hats are anodized. AKB springs are available at an additional charge.
Overall Kit Prices
StopTech ST-60 Trophy= $4145
Essex Designed AP Racing Competition Big Brake Kit= $3,599
StopTech ST-60 BBK= $3,395
Our complete kit pricing falls between the two StopTech six piston kits.
Racing Pedigree and Brand Equity
While I'm far from a brand snob, I'd say it's safe to say that AP Racing gets the nod in terms of brand equity, racing heritage, and pedigree. StopTech has had good success in the lower ranks of racing (World Challenge, Grand Am, etc.), but AP dominates at the elite level. Virtually all of the factory BMW race cars use AP Racing (as noted earlier in this thread), DTM, etc. Not to mention AP dominates many of the 'money-no-object' markets when teams have a brake choice (non-spec) such as NASCAR Sprint Cup, Super GT, ALMS etc. (which btw are extraordinarily tough on brakes, even though they're typically going in a circle!).
Which Kit to Choose?
Compared to the ST Trophy kit, I'd call it a no-contest. The Trophy Kits are modified street components designed to work better on track. They have more 'race-like' features, but they are still limited in their capacity by the aluminum pistons, a low disc vane count, and heavier weight vs. our purpose built race caliper and disc. The Trophy base price is over $500 more than our kit, and the specification on the components aren't as high as they are in our kit. As such, I don't expect the components will last quite as long at track temperature vs. the ones in our kit (pads, discs, etc.). I believe our system is a significantly better value.
While our system is a bit more expensive than the standard StopTech ST-60 kit, you're getting a lot more technology for your money. If you peruse the list above, you'll see that every component in our kit meets or exceeds their specification, and is more closely aligned with professional-level race components. That is intentional. When you factor in the fact that the higher specification components will need fewer replacements, the running costs over a year or two will balance out quickly, essentially negating the initial price difference. You'll also be saving about 9-10 lbs. unsprung weight per front corner with our kit!
If you can't live without a giant 380mm disc, then obviously the choice is also clear.
Summary
Ultimately both companies make a great product. I had an ST-60/ST-40 14" BBK on my Z06 while I worked at StopTech (and an ST-40 kit on my 350Z). Both were solid products made by good people. I'm also still friends with a number of their employees (since I hired and trained most of their current sales staff). When we put our Essex Competition Kits together however, I tried to look at every piece of the StopTech system and produce something that eclipsed its performance, all while keeping the costs at a level that the average enthusiast could afford. My past employment there put me in a perfect position to accomplish this task, and I believe we have succeeded...more technology borrowed from pro racing, higher specification, lower running costs, better fitment, etc. I believe what we're doing is taking things to the next level for the average club racer, HPDE student, and autoX'r, and giving them access to previously unobtainable technology and performance.