Dirk Miller

I enjoy a half dozen HPDE outings each year with my ’08 C6 manual. Since I usually have a passenger ride with me as we participate in level 4 NASA events, safety has been a major focus of mine. Having cooked my brakes 4 or 5 times, I see my brake system as the weakest link in my car so far. With this in mind, I’m considering Big Brakes. Due to the cost of this upgrade, here is my question. Can I install a big brake such as AP CP5060 6 piston or Brembo 6 piston only on the front and be happy?
The following is a list of my upgrades I’ve installed so far: Pfadt Light sway bars, SKF hubs, DBA slotted rotors, Raybestos ST43 pads, SS brake lines, Quantum Cooling ducts, Dewitts radiator, Setrap power steering cooler, Accusump, Z06 oil cooler, CAI and Z06 exhaust manifolds cats and H pipe (424 Rhp), race seat, harnesses and Brea Kraus bar. Once at the track I change out my toe in and camber for use with Hoosier or Avon hard compound slicks. Along with brakes, I will be exchanging out my F55 magnetic selective shocks to coil overs plus I plan to install LG motorsport poly bushings.
So, for a budget minded guy who does his own work what might I expect if I only upgrade the front brakes?

63Corvette

I have Stoptech ST60 (front) and ST40 (rear) and love em.
That said, I expect JRitt (http://www.m3post.com/forums/showthr...=921567&page=3 )to weigh in, and his brake packages are respected and used by most of the wheel to wheel (SCCA and NASA) racers here on the Forum. I personally would do a matched set front/rear, but I believe that many racers are using stock rear brakes on track (with modern race pads and fluid, of course)

UrbanKnight

AP Racing big brakes here on my full tilt z06 with STOCK rears.. No issues or concerns... You are fine with just bigs in the front... 70+% of the stopping force is from up front...

Bluefire

+1 for AP Racing

I'm tracking a C5 with their Endurance kit in front (stock rear calipers). They are far superior to the stock calipers. I no longer fear late braking. gained ~3 sec. a lap.

naschmitz

I ran with the Hardbar/AP Racing T1 kit in front with stock rears from 2010 until last November on my 06 base coupe. System is a big step up from stock and was highly affordable. I just recently upgraded to the Radi-CALs and an Essex rear kit but that is about 3X higher cost.

Charley Hoyt

I was in this position a few years ago. I ended up with the Stop Tech ST60/40 set up and really liked them. They worked well on the street and on the track. I seriously considered one of the floating rotor kits that is extremely popular on this forum.... Until I went for a ride in a car that had them. They were a great set up for the track but I wouldn't want to live with all that noise on the street. They rattle a lot... My experience was a few years ago so things may have changed, but you still can't go wrong with the Stop techs

Charley

NemesisC5

Didn't know floater discs would be that loud...good info Charley.

Last C5

Stoptech 60s in front with stocks in the rear. Never been a problem. Make sure you check the cost of expendable parts for any system you buy.

naschmitz

The Hardbar/AP T1 kit with Gary's hats and bobbins were quite loud with the rotor rattling around the hat as the disc rotated. The beauty of that kit was that you could easily swap in a stock rotor for the street and eliminate the noise when you swapped back to street pads.

I can tell you that the Essex floating rotor setup with the anti-knockback spring clips work very well.

NemesisC5

I was told by PFC that the floaters that performed best were noisy because they needed a certain amount of flexibility to perform as designed. I think his comment was primarily targeted at friction/drag of the rotor against the pad when no brake pressure is applied.

JRitt@essex

The key issue is the brake torque output of the kit in question. As long as the kit you're considering is sized properly, it can integrate seamlessly with your OEM rear brakes. All of our front Essex/AP Racing kits are designed to have the appropriate brake torque output with the stock master cylinder and the OEM rear brakes. We accomplish that through careful sizing of both the caliper pistons and the disc diameter. FYI, StopTech also sizes their front kits properly to mate up to the OEM rears. That said, our kits have a laundry list of benefits over StopTech's offerings. I'll post those differences below in a separate post.

As you've surely seen, the front brakes are the weakest link on the C6. You'll typically go through 3-4 sets of front pads for every set of rears. Addressing the front with the best brake system you can afford is the proper solution, and will give you the biggest ROI.

We have an array of kits for all budgets and needs. Click here to see all of our kit options for the C6. For your particular setup, one of our 355mm/six piston kits would be a perfect choice. The 372mm kits would be overkill for you. They would add unnecessary unsprung weight and cost. The 355's will work great for you, especially since you have a proper brake duct solution.

For your car and situation, these are the two kits I would focus on:

Front CP5060/355mm

Front CP9660/355mm

The discs are identical in the above kits. Both use our 355x32mm, 72 vane disc that won the Daytona Prototype Championship in 2012 on the Action Express Corvette DP's.

The difference in those kits is the caliper. The CP9660 uses AP's latest Radi-CAL technology, which makes the caliper stiffer, lighter, and cooler running. They're slightly more expensive, but they are the latest and greatest, and far beyond any bolt-on solutions our competitors offer at any price.




Below is some additional info I posted in another similar thread recently.

Over the past decade I've helped hundreds of C6 Z06/Grand Sport owners with their brakes. There are some serious deficiencies in the OEM brakes on that car, with both the calipers and discs. While throwing band-aid solutions at the car appear less expensive, they will end up costing you in the long-run. Even more importantly, they will perpetually inhibit your fun with the car, and limit your ability to improve your consistency and confidence.

The OEM calipers are not particularly effective. You've already seen all of the issues with the one-piece pads vs. padlets, funky pins/bolts that make swapping pads a hassle. Those calipers also weigh a ton, have aluminum pistons, not terribly stiff given their mass...the list goes on.

The OEM discs don't flow much air, they're heavy, not terribly crack-resistant...again, the list goes on.

For those on a budget who are serious about tracking their car, my recommendation on this particular trim level (C6 Z or Grand Sport) is to go with the best front brake system you can afford. Most people go through 3-4 sets of front pads and or discs for every set of rears. The front is where these cars have the biggest issues, and where you'll reap the greatest dividends from a complete big brake kit. The OEM rears have all the same problems as the front, but they aren't as much of an issue because they simply don't see as much abuse as the fronts on these cars. Later on if you decide you need, or just want, a rear BBK, we have matching ones that can be added on and will integrate seamlessly.

Rather than going with 2-piece discs at all four corners, that money will be far better spent if you go with a killer front brake kit and just continuing on with the rear setup you're running now (upgraded rear pads, discs, lines). The rears will hold up okay, and there is no sense throwing money at the rear if they aren't problematic.

Here's what one of our complete front brake kits will give you:
1. Confidence- There's no replacement for diving into a turn from any speed, on any track, and not having to even think about your brakes. Our customers mention this word over and over again when describing our kits vs. the stock brakes.

2. Consistency- That confidence comes from consistency. Our brake kits allow you to run all day, every day without any chance of fade, and the brakes feel the same on the last lap of the day as they did on the first.

3. Convenience- You won't have to bleed between sessions. Some of our customers don't even bleed their brakes between numerous events. You won't have to fiddle around with weird hardware to swap pads, and it will take you longer to jack the car up than it will to change pads. Our kits use a pad shape that is available in every compound from every manufacturer. We also now have a bunch of people running our kits out at the track, so someone may even have spare pads on hand if you need them in a pinch. You'll be able to hang out and relax between sessions, rather than messing with the car and potentially missing out on expensive track time when they call your run group.

4. Cost- The up-front cost is higher to go with a complete front BBK, but it will save you money in the long-run. The longer you own your car, and the more frequently you go to the track, the more money you will save. One of owners on the BRZ forum wrote a cool "cost/benefit" review. He shows that our brake system paid for itself in less than a year, just on consumables savings (pads and discs). He helps run Chin Motorsports and is constantly tracking his car more than most, but it exemplifies the cost savings associated with a proper brake kit designed for heavy use. The biggest factor is that when you sell your car, you'll be able to pull off our kit and recoup 60% of your initial investment. If you spend $1,600 on two-piece front and rear Girodiscs now, you're not going to get much of anything back for them after beating up on them for a couple years. If you bought our six piston/355mm kit for $3,599, you'd likely get $2,000 back for them after running them a few years. That means your out of pocket over the long-haul is going to be about the same ($3,599-$2,000=$1,600). The big difference is that during the next few years you'll get to enjoy all of the benefits of the BBK listed above!

We recently had a Gen.5 Camaro owner come to us in a similar situation. He was running the six piston calipers off of the ZL1 on stock-style discs. He had all of the same issues we see with the C6Z/Grand Sport OEM setup...charred paint, melted dust boots, leaking bleed screws, etc. You can see a good list of the benefits of our AP Racing calipers vs. OEM painted road calipers in this blog post.

For your car I'd recommend one of our systems with a 355mm disc and six piston caliper. They will give you all you need. If you plan to go with a forced induction setup, one of our 372mm systems would be a consideration. Otherwise the 355mm kits will be perfect.

Our standard Essex/AP Racing CP5060/355mm kit is IMO the gold standard for this chassis. We have hundreds of these kits on tracks all over the world doing HPDE, Time Trials, AutoX, and wheel-to-wheel racing, and they have proven bulletproof. The 72 vane AP Racing discs in this kit were actually used in 2012 to win the Daytona Prototype championship...they are stout!






Our recently introduced Radi-CAL kits ratchet things up another level and have a few more options. You can see discussion of our Pro5000R Radi-CAL kits in this thread. The CP9660/355mm kit uses the same discs as the above kit, but the caliper adds considerable stiffness and weighs a little less than the conventional caliper design.








Our CP9668/355mm kit uses a 25mm thick pad. It's far from a necessity, but if you don't want to fiddle with pad changes, that big 'ole inch thick pad burger will give you a LOT of freedom from messing with them!









Support is another big issue. Down the road, are you going to have spare iron disc rings available when you need them? Will you have someone who can rebuild your calipers in a few years when it's time to sell them? Will you have someone to consult if you run into an issue, have a question, or want to discuss which brake pad to run? With Essex/AP Racing, you will. We've been in business over 30 years, and also forum sponsors for about 6 years now. We also frequently email and talk with customers while they're out at the track on the weekends. We know brakes, and we know these cars:


Is our front BBK a big investment? Yes it is. That said, we have never had a customer tell us that it wasn't worth what they paid. Even though our kits are the most expensive on the market, our customers consider them a great value. Most tell me it is the single biggest improvement they've made to their car for track days. The C5.R, C6.R, and C7.R's have all won Le Mans running AP Racing brake kits during the past 15-20 years. They don't run AP because they're cheap, they run them because they are the best available at any price. You can go with lesser equipment from a different brand, but none offer the laundry list of benefits that our kits offer. My advice if you can swing it is, "Do it once, do it right." All of our customers tell us they wish they had done our full kit sooner, rather than incrementally trying twenty six different things until they got it right. Our kit will free you up to worry about other things while you're at the track, not brakes. It will pay dividends for as long as you own it via low running costs, and when you sell it, it will pay you back again due to the high resale value of the premium AP Racing brand.

Feel free to ask any questions via PM, email, or phone. We are open from 8am-5pm ET, M-F, and you'll always get a live person on the phone.

JRitt@essex

"How does your kit compare to StopTech?" is a question we get from customers almost every day. Below is a synopsis I wrote the other day on the BMW M4 forum, comparing our front Pro5000R Radi-CAL BBK's to StopTech's ST-60 kits. In this particular instance I was comparing our 372mm kits to their 380mm kits. All of the basic points hold true when comparing our 355mm kits to their 355mm kits as well.

For reference, I was the sales manager at StopTech for 4-5 years back in the early to mid 2000's when they were getting their legs. I also ran the StopTech ST-60 system on my C5 Z06 for several years while I worked at the company, so I'm intimately familiar with their products. It is an excellent system with high quality parts. When we designed our Essex/AP Racing kits however, we set out to make every component in our kits lighter, stiffer, more durable, than anything else on the market. I believe we have succeeded.

Calipers

Core Design
The StopTech ST-60 is a basic, no frills, conventional design from roughly year 2003. It was designed to be as versatile as possible to service a wide range of vehicles from sports cars to trucks out of the same casting. Over time it has undergone some changes, moving from a casting to a forging, losing a little weight, etc. It is a quality road caliper. The Trophy version was conceived in roughly 2009. It is the same caliper with a bit of fat trimmed, and the option of running AKB springs at an added cost.

The Pro5000R Radi-CAL's, CP9660 and CP9668, were designed in 2014 using AP's collective knowledge gained from roughly 7 years of Radi-CAL designs in Formula 1, NASCAR Sprint Cup, DTM, etc. You can read about The Radi-CAL design philosophy here, and the huge impact they had at the elite level of racing. The primary benefits of the Radi-CAL design are:

• Massive Stiffness Increase- A 30+ % increase in both static and dynamic stiffness allows for far less deflection under load, which means superior pedal feel & modulation, more even pad wear, and longer caliper service life.

• Considerable Mass Reduction- Removing all extraneous caliper mass lowers the caliper weight, despite the huge stiffness increases

• Optimized Airflow- Air moves around and through the caliper more efficiently, providing superior heat evacuation.

• Efficient Packaging- The wide, asymmetric caliper profile and internal porting allows the caliper to fit into tighter spaces.

From a technical standpoint, the Radi-CAL design makes everything else on the market a bit of a dinosaur. They are the current state-of-the-art in caliper design, and the gold standard in elite racing.

Anti-knockback springs

AP Racing has them, StopTech doesn't, unless you pay extra for their Trophy kit. 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= Domed-back, ventilated, machined stainless steel

Stainless is far superior at keeping heat out of your brake fluid. The domed-back provide added stiffness and superior pedal feel, and the ventilation also allows them to run cooler. StopTech will tell you that SS pistons are a problem because they expand at a different weight than the aluminum caliper body when they are heated, which can lead to piston cocking and problems. That is complete rubbish. Every serious racing caliper on the planet runs either SS or titanium pistons. I've been with Essex/AP Racing for seven+ years now, and we've sold thousands of calipers with SS pistons in the aftermarket at this point, and we have NEVER had an issue with a piston cocking, etc. Literally, not once.

Weight

AP Racing CP9660 Pro5000R weighs 6.2 lbs. without pads. Our CP9668 (which is wider and takes a 25mm thick pad) weighs only 6.8 lbs. The StopTech ST-60 weighs roughly 8.8 lbs.

Dust Boots

StopTech uses a street caliper, and as such uses dust boots. AP Racing Competition calipers have 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

StopTech has an external crossover pipe for fluid, and outer bleed screws, while the Radi-CAL Pro5000R's have internal porting and don't even have an outer bleed screw. This feature protects the hydraulics from track debris, and when you're swapping wheels. No chance of knocking a bleed screw or bending a crossover tube.

Materials and Bridge

The caliper bodies on the ST-60 and Pro5000R are both high quality forged aluminum parts. The bridge on the AP uses two bolts and is easier to manipulate. On the CP9668, a spring clip quick-change bridge option is also included, which reduces pad change time to about six seconds. You squeeze the spring clip and lift...that's it, no tools required! (see pic below). With four bolts, the bridge on the ST-60 can be a hassle to get in and out. On my car I had to wrestle with it a bit to get it seated properly.


Pad choice/cost/size

Both the ST and AP calipers use an old AP Racing pad shape and have tons of pad options. The radial depth on the Pro5000R calipers is 54mm vs. 51mm, so you get a tiny bit more pad volume with the AP's. Thickness on the ST-60 and CP9660 is 18mm, but our CP9668 offers 25mm thickness if you're endurance racing, or if you're just lazy and don't like to change pads as often!

Stainless Steel hardware

Both calipers have good stainless steel hardware.

Footprint/size

In addition to weighing much less, the CP9660 has excellent wheel fitment, partially because it has no outer bleed screws and it is tapered on the corners. It fits inside OEM 18" and 19" F80 wheel options without a spacer. Despite being considerably wider, the CP9668 is still a compact package and will fit many wheels.

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 (again see the OEM caliper below turning green). 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. You can send your calipers to Essex and have them rebuilt by the same techs who service NASCAR and IMSA teams. I'm unsure of ST's procedures, policies, and prices on rebuilds at this time.

Discs

Design
Both companies offer high quality discs for the kits in question. Discs from both manufacturers are quality castings that are crack resistant and will last a long time under heavy track use. That said, the StopTech discs are a more pedestrian 48 vane design, whereas the AP Racing discs have 84 vanes (nearly twice as many). That means more disc face stability and higher airflow. Our discs also have the patented J hook face slot are the #1 choice at the elite level of motorsports (NASCAR, IMSA, DTM, Aussie V8, Super GT, etc.). That said, there are plenty of World Challenge and Grand Am teams running StopTech discs with great success.

Size/Mass/wheel fitment
The discs in the front StopTech kit are 380x32mm. Our front discs are 372x34mm. Both are very similar in weight at roughly 21 lbs. The big difference is that we've packed more mass into a smaller package, which makes a big difference when trying to fit behind 18" wheels. Our discs are thicker and have nearly twice as many vanes, and you'll have more wheel fit options.

Spare iron price
StopTech 380's are $360 each, and our 372mm discs are $399. We believe that small cost difference is more than offset by the technology and longevity embedded in our discs.

Disc hats

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

Disc Burnishing
For $100, Essex will burnish your discs with the pad compound of choice. That means you don't have to fiddle around with bedding-in your discs, or worry that you're doing it properly. Our patented burnishing machine and process make sure it's done properly every time. We burnish thousands of discs each year for pro race teams. StopTech does not offer this option/service.

Brake Lines

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

Other Factors

Initial Purchase Price

StopTech ST-60/380mm kit=$3695
StopTech ST-60/380mm Trophy Sport Kit= $4495 (if you want dust boots, it's more)
Essex Designed AP Racing CP9660/372mm kit= $4099
Essex Designed AP Racing CP9668/372mm kit= $4499

Obviously I'm a bit biased, but it's almost inconceivable that anyone would pay a similar amount for the aging StopTech technology vs. our latest AP Racing Pro5000R offerings. The Pro5000R Radi-CAL kits are a step beyond the ST kits in every facet. Yes, our kits are initially ever-so-slightly more expensive than the basic ST-60 kit. However, there is a HUGE difference in the level of hardware you're getting in each kit, all for a meager few hundred dollars. Our setup is something similar to what you find on various factory BMW race cars. Every component is designed to be stiffer, lighter, and more durable than anything else on the market. There's nothing even close.

Brand/Reputation/Panache
StopTech has a solid reputation for supporting grassroots racers, providing quality parts at an obtainable price (I like to think I was actually a large part of building that reputation early on ). Lots of lower-level racing series use ST products successfully.
AP Racing is the best of the best, with over 700 Formula 1 wins on their brake components. Just about all factory BMW race cars run and trust AP Racing. They have the most cutting-edge products, and when people see the AP Racing logo, they think "the best."

Aesthetics
The OP was concerned with aesthetics, so I'll throw this one in there. Other than not being available in fancy yellow or blue paint, I don't think it's a remotely close comparison as to which kit looks better. Behind the wheels, 380mm discs effectively look nearly identical to a 372mm. The radius of the 380mm disc means it only sticks out 3mm closer to the wheel on either side vs. a 372mm, which is negligible visually. The J Hook slots also look way cooler than a straight slot.

The ST-60 caliper makes the AP Racing CP9660 and CP9668 look like spaceships! The M4 is a technology-laden car dripping in carbon fiber and all of the latest gadgetry. The AP Racing calipers are much more inline with the overall high-tech feel and aesthetic of the M4. Which one of these screams technology and high-end?









StopTech underside vs. Pro5000R






In summary I'll say that I'm not trying to bash StopTech. I have nothing against them, and they make nice products. I also still have friends who work there. That said, time has moved on. We now have superior technology and offerings available to the average enthusiast that weren't an option 10 years ago. We've had a number of customers switch from an old StopTech system to one of our new systems, and I have yet to hear from one who wasn't pleased with their decision to make the switch. Onward and upward.:thumbsup:

meldog21

100%. I spent a bunch of time and money doing slight upgrades to the brakes on my C5 Z06. I naively thought I could make the brakes work for A group trackdays with cooling, better pads, etc. The brakes never held up and I kept having to repair, replace, and maintain, instead of driving without worrying about the brakes.

After all the trouble I had I finally bit the bullet and spent a few thousand on a Full StopTech set up with spindle ducts(I had to purchase larger spindle ducts to go with the larger rotors, replacing my smaller spindle ducts). Now I can just drive with confidence.

I am not endorsing one brand over another, just agreeing with the four points above. Its not cheap to go to a complete high quality brake system, but it is so worth it. Now my car is like my motorcycle, I never have to worry about my brakes.

By the way, those AP brakes do look nice. Oh, my StopTech brakes that were red when new are now brownish red after many hard sessions.

Just spend the money and get a good quality set up. You will be happy.

Dog

TKOGTO

Dirk - you can absolutely run a good BBK setup in the front leaving the rear stock and be in good shape. I did it for about 2 years and added the matching Wilwood rears only after growing unsatisfied with getting a good complimentary rear pad in stock shape to match the Wilwood H pad I use up front. If you can find a good match with the AP (or other) setup, the only other issue is the PITA pad change with the stockers. Brake performance wise, BBK front/OEM rear is just fine.

I am curious about what you meant by cooking the brakes. With those cooling ducts, pads and I assume appropriate fluid, the brakes should survive OK.

Dirk Miller

Well I know I need to continue to improve on my braking techniques and realize i've been a pretty hard braker as compared to smooth. At Thunderhill I heated the front calipers to where the right front spread out an 1/8" and I had to replaced with a new oem caliper on the passenger side. As stated earlier brakes totally have left me 4 times. My brakes haven't lived up to the grip of the Hoosier scrubs that i've been using. Turn 2 at laguna Seca is quite demanding on the brakes too.

JRitt@essex

Race tires eat brakes. We had a C5Z customer (chief instructor for Turn One at CMP) who was rebuilding or replacing OEM calipers every other event because he was running into the same thing.

The car in the vid below is equipped with our standard front CP5060/355mm Essex/AP Racing BBK...gives a good idea of his brake markers on a track you're familiar with, and what the brakes can do.

63Corvette

GREAT video!!! That shows what the track "line" looks like at speed.

Brandon's Z

Great info but doesn't apply to me. I have a 1990 Zr1. I am trying to understand the best way forward and I guess my biggest question now is do I need to upgrade my calipers. I think I have come to the 100 % conclusion to upgrade for many factors, but now I need to figure out what the best upgraded caliper is and use a system around that caliper. I couldn't find stoptech or Ap for my car and the brembo set up I have to upgrade wheel and tires. Not desired

Now I looking at Wilwood 4p vs 6p and Baer. What are your thoughts between those two or anything else I should be considering. Sorry I looked and look through the threads but can't find good info on C4 calipers and best replacements for 17" wheels.

FASTFATBOY

OP what is your current setup?

Pad

Rotor

Fluid

Tire

Any video f you on track?

Brandon's Z

Current set up
Stock calipers
HD napa rotors
Raybesto pads
Ate fuild before events
Nitto tires