Soma07

Need some feedback for those of you out there with the AP Sprint kit or Hardbar T1 kit.

For reference purposes Sebring is my home track and its pretty brutal on brakes. My car is a C5Z06 that's nearly stock. I'd consider myself to be a intermediate to advanced driver and my quickest lap there is a 2:29 (on street tires).

1. Is anyone running the Quantum Competition duct kit with the AP J Hook rotors? Diameter wise my measurements show it would be really close. Not sure how far the AP disc is offset vs stock though.

2. What kind of life are you seeing out of the J Hook rings? I know they are quality parts but I have to wonder what their limits are being only 12.8".

Right now I'm only seeing 3 days (12 sessions) out of a set of OEM style rotors (fronts) before the heat cracks get to the edges and I don't feel comfortable running them anymore.

3. What the pad life like? Any noticeable difference in pad life or performance with the D50 pads vs the D41's?

I've been running Raybestos ST43 pads in the OEM calipers and I'm pleased with their durability. 6 days so far and they probably have one more in them. I do feel like they have too much initial bite for street tires so I'd probably try the DS1.11's in the AP calipers.

4. Lastly if you had to do it over again would you go with the same setup?

Thanks!

StreetSpeed

1. This is the setup I run. You'll need to do a smidge of bending or dremelimg to make everything fit and not rub but not much.

2. I would go through plain rotors in about 3 days. Since adding the AP Kit last June, I haven't replaced a rotor. Off the top of my head that is 2 days at WGI, 2 days at Mt Tremblant, 2 days at VIR, 2 days at Summit, 2 days at NJMP, and 1 day at Limerock. I might be missing another couple days somewhere. They've got several more days left in them.

3. I'm using Ferodo ds11 or something and pad life is at least double what I was getting from Carbotech XP20.

4. Only regret is I didn't do it sooner. FYI last year was my first year in the Vette but I've been driving on track since 2006 and instructing since 2010. The car is too damn fast to not be confident that every time you hit the brakes the car will be rock solid. I never felt good about the brakes in the C5Z til I switched to the AP kit. Now it's the last thing I worry about.

argonaut

OEM rotors are interchangeable with the AP rings and Harbar hats - no shims or other adjustments necessary. Therefore the offsets should be the same and the Quantum duct kit should work. I used the non-competition Quantum duct kit and had no issues.

I was getting about 10-12 days (~38-44 sessions) out of a set of rings. Thats mostly on R-comps and driving in advanced run groups.

From the data I have handy it looks like I got 8 days (30 sessions) out of a set of DS1.11. I'm not sure if those were D50 or D41 - I have run both and don't recall an appreciable difference - but I don't have the data to back that up.

The DS1.11 pad does not have a whole lot of initial bite. That's why some guys don't like them. They do have fantastic modulation. Some pads, like DTC70, are an on/off switch and its really easy to get into the ABS. DS1.11 is not like that. They are a really good track pad to use when you have street tires on.

For your stated usage the AP 'Sprint' kit sounds perfect. To me the biggest positives are: fits under 17" rims, cheap pads, can use stock rotors, no tapering, good solid, dependable performance. It's nice to be able to get to the track and forget about your brakes with the knowledge that they will be there for you - no bleeding between sessions, no rotating pads and replacing cracked rotors every other day.

Take everything people say here with a grain of salt. Driving style, ability, tracks and setup have a huge effect on brake performance and wear. I'm probably a little harder on brakes than most - experienced and aggressive enough to really exercise them but not good enough to be one of the really fast guys who turn lap times 4-6 seconds quicker than me and yet seem to get twice the number of sessions out of a set of rings.

JRitt@essex

I'll answer your questions based on customer feedback I've received, which is abundant. You can see a couple reviews of the kit that I just posted on our blog yesterday as well. They give some indication of disc wear.

The disc in our Sprint Kit sits on the same plane/same offset as the OEM disc on a C5. We always recommend a good cooling setup, and I know some of our Sprint Kit customers are running the Quantum kit. The one thing you need to be very careful of is do not bolt anything between the caliper bracket and the upright. Doing so effectively changes the offset of the bracket and caliper and can lead to serious problems such as disc and caliper contact. In other words, you need to make sure the caliper and disc are sitting where they were designed to rest. Anything modifications that change those planes will obviously create issues.

This one is going to be all over the map, as there are a ton of factors involved...track, driver, power, tires, etc. The AP Racing J Hooks are incredibly efficient vs. OEM-style discs, and you will see considerably longer life out of them. It's really, really tough to put a number on it though.
I've heard mixed results from customers on this one, but the preferred pad that we've been recommending is the Ferodo DS1.11 in the D50 radial depth. They are awesome pads and we have a lot of converts using them since they've taken the plunge. They last a long time, have a great linear torque curve, aren't tough to bed-in, and are generally pretty easy on discs.

We've had a whole bunch of guys run the T1 and Sprint kit in HPDE, Time Trials, and wheel-to-wheel racing. It has won national level races, and is quite capable.

So far I think I've only had one customer out west who was clearly exceeding the heat capacity of our Sprint system on a C5 Z06. He was running Miller Motorsports and he was just putting too much heat into them. He sold his setup and moved up to our six piston Endurance kit. To my knowledge that cured all of his issues.

To my knowledge I have not had anybody fade our 355mm Endurance setup on any Corvette...C5, C6, or C7.

It's a tough call on which way to go. Clearly if you are running 17" wheels, the Sprint Kit is the obvious choice as our bigger kit won't fit. If you're running 18" wheels, you can go either way. Here's a basic breakdown:

Sprint Kit advantages over our Endurance Kit:

• $1,000 lower initial purchase price. Keep in mind though that the kit's resale value when you move to your next car will reflect the purchase price. In other words, if you sell the Sprint Kit used for $1599, you'll likely be able to sell the Endurance Kit for $2599. So this point is really a wash if you have the money to spend presently.

• Saves a little more weight vs. the larger 355mm kit...roughly 1-2 lbs. They are very close in weight though, with both saving 8+ lbs. per corner of unsprung weight. Even though the 325mm disc is smaller in diameter vs. our 355mm, it has thicker faces and actually weighs almost exactly the same. The weight difference between the kits is in the caliper/bracket/pads.

• OEM style C5 discs can be run with Sprint Kit if necessary

• Spare 325mm disc prices are lower ($249 vs. $359 for the 355mm)- That said, the larger ones will likely need less frequent replacement

• Spare pads are less expensive for the four piston vs. six piston ($200ish on average vs. $300-$400 on average)- same situation with the discs though...the six piston pads will likely be replaced less frequently. The four and six piston pad shapes both have countless friction options available for them.

• Clears OEM C5 Z06 17" front wheels

• Pad change is one bolt vs. two bolts, but both are super easy.

Endurance Kit advantages over our Sprint Kit:

• Larger 355mm disc spreads heat over greater surface area, and has 72 vs. 70 vanes.

• Pad has larger surface area, and again spreads heat a bit more vs. the more compact pad shape used in the Sprint Kit
• Six piston caliper has ventilated, domed back pistons (vs. flat back, non-ventilated pistons in the four piston). These features give a firmer pedal feel and provide additional cooling to help keep heat out of the brake fluid.

• Machined logo vs. painted logo on the four piston. Some people like that the machine logo won't get messed up by brake fluid, whereas paint will. On the other hand, some think the painted logo looks better or is more eye-catching.

• Can be used with C6 Z06 OEM-style front discs when a 0.8mm shim is installed between the caliper bracket and upright (see our site for details)

• Fills 18" wheels out a bit more so you can say, "Look at my big brakes!" as you blow past someone into turn 7 at Sebring.

Commonalities between our two front kits:

• Both save a ton of unsprung weight. Okay...maybe not literally a ton, but 8-10 lbs. per corner.

• Both have stainless steel pistons with anti-knockback springs, and no dust boots

• Both use uber-common pad shapes

• Both use heavy duty AP Racing J hook discs that take a pounding and then some. Spare discs are reasonably priced vs. competitors, and actually a tremendous value when you look at their longevity.

• Both clear OEM Z06 wheels without spacers (Sprint clears C5 Z wheels & C6 Z wheels, and the Endurance clears C6 Z wheels)

• Both use an anodized finish which holds up better to track heat and brake fluid vs. painted calipers.

• Both have a simple pad change with 1 or 2 bolts

• Both use the same float control/anti-rattle disc & hat attachment hardware.

• Both come with Spiegler SS brake lines

• Both kits qualify for our caliper rebuild service for as long as you own the kit

• Finally both of our front kits integrate seamlessly with our rear kit if you ever decide to go down that route, so no issues there.

Either kit will most likely get the job done for you. In my eyes, the larger Endurance Kit is sort of the final word in terms of a long-term brake solution. It spreads the heat around a bit more than the Sprint Kit, and has a few nice additional features like the whizzy ventilated pistons (that's a technical term). Unless you're running 24 hour races, it's likely going to be all you'll ever need. You wouldn't have to replace pads or discs quite as frequently as you would with the Sprint Kit, and possibly wouldn't have to bleed the brakes as frequently either. For these reasons I generally view it as the slightly 'less risky' proposition for customers who are on the fence between the two kits. It is a bit more expensive in terms of both initial purchase price and spares, but consumables will likely last longer, and you'll get more money back for it used. So the cost difference is really a bit of a wash assuming you have the extra grand available up front.

That said, the Sprint Kit packs a huge wallop despite the slightly more diminutive components, and it is a tremendous value. The discs are small in diameter, but are incredibly stout. There's nothing else on the market even close in terms of overall feature set vs. price. It is a tad bit lighter, offers a little more flexibility in terms of wheel choice (17's), and consumables are a little less expensive per purchase. Again though, the running costs likely balance out however. For most customers, the Sprint Kit will get the job done, but there will be the occasional driver/maniac who will exceed its limitations. Usually those customers would be in a modified C6 Z06, supercharged, running steamroller Hoosiers, etc. For someone on street tires, I can't imagine them ever having any problems with the Sprint Kit.

Hopefully that is helpful. You're doing the right thing to ask actual users however. There are a number of guys out there who have moved from either the T1 or Sprint to the Endurance Kit.

Let us know if you have any other specific questions, and thanks for considering our products.

JeremyGSU

I have an '04 Z making 392whp with the old Hardbar T1 kit and stock rears. I run XP20 / XP10 pads. I have the Doug Rippie brake duct kit and LG spindle ducts. Sebring is also my home track and my fastest lap is around a 2:24.

I would say I'm not really seeing that much better life out of my rotors than when I was running the stock calipers and XP12's. Probably 6 track days or so, or 3 weekends. I blame this on the fact that once I got the new kit and saw the car stopped consistently I started braking harder than before. Now I am practically standing on the brakes at 95% of what it can do at every corner. So while the material is better and should last longer I'm not braking the same as before so it's not a fair comparison. Sebring is hard on brakes though and everyone "brakes" different as mentioned above. I also would not compare what people run at other tracks. If they don't run Sebring as home, throw out the data. When I track at Road Atlanta I hardly touch the brakes compared to Sebring. My pads and rotors would last forever there, but that doesn't really tell you much does it? Some tracks don't use the brakes much. I also have found instructing that people who say they are braking "hard" often, aren't. I have caught people hard in braking who have full Wilwood 14" front and rear kits while I only have a 12.8" kit and stock rears. So braking is subjectable.

I also do not change my rotor rings in between events and drive on the street with the same rings to/from the track as well as around town. I just switch the pads to a Carbotech street pad. So my life is less because of that for sure.

You're going to get heat cracks on the AP rotors too. Until you actually crack them you need to keep running them. My AP rotors pretty much get heat cracks the first weekend at Sebring.

I tried a Forado pads once and didn't like them. I did make the mistake of using them on the street but I still didn't care for them that much. They came apart off the backing plate. I will say I go through the Carbotech pads QUICKLY and have considered trying something else. I go through a set of 20's in less than 2 weekends, or right at it.

I like the AP setup and it works much better than before. However, I have NOT had the luck of getting any kind of regular rotor to fit within the caliper other than the Hardbar 2-piece rotors. They just hit the caliper. I have tried DBA, NAPA, and stock. All of them did not fit. Kind of frustrating. The kit does clear 17" wheels so that's nice.

If I had to do it all over again I would have spent the extra money and gotten a Stoptech front and rear kit big brake kit. It would have been more money so it's not a true fair comparison but I just feel like I am working this little 12.8" kit too hard. I got sold on all the little "features" that make it "better." but that little kit is just trying to do too much for the speeds I'm going. I think a 14" kit would have been a better idea. However, this kit does work well.

I will also say what's great about the 2-piece is they never warp. I never have had the sensation of shaking since I've switched to this. They heat crack and will then crack all the way through and still never warp. I love that feature.

Hope this helps.

Rob Willis

Soma07: I sent you a personal message.

0Randy@DRM

I have a customer that runs Sebring all the time. He just ordered his 4th set of pads and no talk of rotors yet. So I would say he is doing very well on the J-hook rotors. He has a proper duct kit! The races are 30 minutes so long enough to be a good data point.

Randy

UstaB-GS549

I run stock type rotors with my Hardbar kit and had to shim the caliper brackets .040" to center the rotor and keep it from rubbing on the caliper. NAPA, Raybestos, Centric etc. all fit fine.

JeremyGSU

Thanks. This sounds like what I am going to have to do.