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Looking at buying either of the above as upgraded rotors for my C7 Z51. The AP J hooks are significantly more cost than the RB rotors. I looked for comparisons and did not see much. Any feedback on them from forum users who may have tried both? Car is used for HPDE type events and the stock rotors are not disipating enough heat causing fade and fast pad wear. I am about a 8/10's driver.
Looking at buying either of the above as upgraded rotors for my C7 Z51. The AP J hooks are significantly more cost than the RB rotors. I looked for comparisons and did not see much. Any feedback on them from forum users who may have tried both? Car is used for HPDE type events and the stock rotors are not disipating enough heat causing fade and fast pad wear. I am about a 8/10's driver.
I'm obviously a wee bit biased, but I'd suggest investing the extra $ into our J Hooks. The initial purchase price is higher, but you need to look at the ownership costs over the few years you'll likely have them. The primary purpose of an aftermarket racing disc is to flow more air and run cooler. Heat is what is causing your issues in the first place. Nothing, and I do mean nothing, will hold up to a beating or flow air like our J Hook discs. Here are few of the big differences between the products:
AP Racing
RB
Air Gap- AP J Hooks have an open path for the air to flow through the vanes. If you look at the RB discs, their hat attachment points block a considerably portion of the disc. The flanges on the iron rings cross over the area where air enters the internal vanes, blocking airflow. The only places where the air isn't at least partially obstructed is in between hat attachment points, which is less than 50% of the disc (there are 9 gaps between the 10 hardware attachment points).
Here's the underside of the AP Racing disc with an open path to the 72 internal cooling vanes:
Compare that to the mostly obstructed path, and considerably lower vane count of the RB discs:
Slot Design- AP's J Hook slot pattern distributes heat far more evenly around the disc than a conventional slot pattern, which leaves cold spots between slots. The J Hook reduces stress across the disc face when heated, and also promotes more even pad distribution.
As for the price difference, you're honestly comparing two different classes of product. The AP J Hooks are the best product available, and are the same design we use in our Competition Big Brake Kits, and the same design that have repeatedly won Le Mans on the factory C5.R, C6.R, and C7.R's for the past decade+ (C6.R below).
In the short-term going the cheap route seems like the path towards saving money. In the long-run however, it will end up costing you more. We see it constantly with our customers who come to us after unsuccessfully trying less expensive products. Also keep in mind that the more times you have to change your discs, the more times you have to take off your wheels and calipers. So even if something cost exactly the same in terms of dollars, it costs you a lot of time and energy to be changing the discs more frequently.
Also, I like to think we offer good support for our products, so you can feel confident dealing with us if you ever run into any issues or need advice. We have guys emailing all the time at night and weekends who are out at the track and asking what I think of their discs, or which pad to use, etc.
Looking at buying either of the above as upgraded rotors for my C7 Z51. The AP J hooks are significantly more cost than the RB rotors. I looked for comparisons and did not see much. Any feedback on them from forum users who may have tried both? Car is used for HPDE type events and the stock rotors are not disipating enough heat causing fade and fast pad wear. I am about a 8/10's driver.
I'm obviously a wee bit biased, but I'd suggest investing the extra $ into our J Hooks. The initial purchase price is higher, but you need to look at the ownership costs over the few years you'll likely have them. The primary purpose of an aftermarket racing disc is to flow more air and run cooler. Heat is what is causing your issues in the first place. Nothing, and I do mean nothing, will hold up to a beating or flow air like our J Hook discs. Here are few of the big differences between the products:
AP Racing
RB
Air Gap- AP J Hooks have an open path for the air to flow through the vanes. If you look at the RB discs, their hat attachment points block a considerably portion of the disc. The flanges on the iron rings cross over the area where air enters the internal vanes, blocking airflow. The only places where the air isn't at least partially obstructed is in between hat attachment points, which is less than 50% of the disc (there are 9 gaps between the 10 hardware attachment points).
Here's the underside of the AP Racing disc with an open path to the 72 internal cooling vanes:
Compare that to the mostly obstructed path, and considerably lower vane count of the RB discs:
Slot Design- AP's J Hook slot pattern distributes heat far more evenly around the disc than a conventional slot pattern, which leaves cold spots between slots. The J Hook reduces stress across the disc face when heated, and also promotes more even pad distribution.
As for the price difference, you're honestly comparing two different classes of product. The AP J Hooks are the best product available, and are the same design we use in our Competition Big Brake Kits, and the same design that have repeatedly won Le Mans on the factory C5.R, C6.R, and C7.R's for the past decade+ (C6.R below).
In the short-term going the cheap route seems like the path towards saving money. In the long-run however, it will end up costing you more. We see it constantly with our customers who come to us after unsuccessfully trying less expensive products. Also keep in mind that the more times you have to change your discs, the more times you have to take off your wheels and calipers. So even if something cost exactly the same in terms of dollars, it costs you a lot of time and energy to be changing the discs more frequently.
Also, I like to think we offer good support for our products, so you can feel confident dealing with us if you ever run into any issues or need advice. We have guys emailing all the time at night and weekends who are out at the track and asking what I think of their discs, or which pad to use, etc.
Using Carbotech XP 12 front and XP 10 rear QUOTE=naschmitz;1590975279]What pads are you using? Any pad that gets heated beyond it's operating range will fade and wear quickly, regardless of rotor.[/QUOTE]
Stay away from racing brake. When i worked at PFC we would collect broken and cracked rotors. We did this to analyze the failures. a rotor is a ware item so like all ware items rotors do fail. We wanted to know if the pad caused it, or if the rotor was poorly engineered. We had a few AP rotors, a few of our own, some brembos, but
We had a 4' tall stack of Failed Racing Brake rotors. they are engineered like garbage. the failures where horrendous. if you value your life stay away from RB.
the part that would fail are these tabs. when the rotor tries to thermally expand these tabs sheer off. this will cause you to lose braking on one corner. That will either lock the wheel, or when you hit the brakes you would spin out of control. even at 8/10ths you would crash.
Last edited by johnny c; Nov 25, 2015 at 10:41 AM.
The first thing you should do is increase the flow of cooling air to the rotors and see if you can extend the performance of your current rotors. Adding cooling air may reduce your problem sufficiently but if it doesn't you will still need it when going with aftermarket two piece rotors.
Another thing is to pay attention to how you are using the brakes. You may be applying them in a way that increases heat retention in the rotor.
All valid points Bill. I have the stock Z51 cooling ducts that "direct" air towards the brakes. Not as good as spindle ducts and that will be next as my driving gets better. According to the PDR data I am not dragging my brakes so not sure what to look for on your second point. QUOTE=Bill Dearborn;1590977031]The first thing you should do is increase the flow of cooling air to the rotors and see if you can extend the performance of your current rotors. Adding cooling air may reduce your problem sufficiently but if it doesn't you will still need it when going with aftermarket two piece rotors.
Another thing is to pay attention to how you are using the brakes. You may be applying them in a way that increases heat retention in the rotor.
I wish I could get the J hook rotors for the rears of my C5. They are amazing as far as wear and performance go. Jeff, do you even have anything that will fit on OEM C5 rears? in a j-hook?
I just want to back up the point Jeff made about customer support. Essex has been fantastic to work with. After every event I'm sending Jeff a bunch of random questions, pictures, measurements, and he's been great about answering them and making suggestions without me feeling like an idiot.
While I can't compare the AP Racing kit to RB I will offer this one anecdote about the importance of rotor design. When I first built my C6Z I opted for the Brembo GT kit with the 355mm 34-vane front rotors. As I got faster I found that the brakes were really operating outside of their temp range and as a result I was wearing pads very quickly and was getting to be pretty hard on rotors.
Brembo suggested I upgrade to their 350mm 72-vane J-hook rotors and keeping everything else the same the difference was night and day. The brakes ran much cooler, pads lasted much longer, and in this case the new pad shape was quite a bit cheaper. So even within a single manufacturer you get much better performance out of the higher end product.
Looking at buying either of the above as upgraded rotors for my C7 Z51. The AP J hooks are significantly more cost than the RB rotors. I looked for comparisons and did not see much. Any feedback on them from forum users who may have tried both? Car is used for HPDE type events and the stock rotors are not disipating enough heat causing fade and fast pad wear. I am about a 8/10's driver.
AP sorry but as others have said spend the money for the quality product. One question what tire are you on?
I'm obviously a wee bit biased, but I'd suggest investing the extra $ into our J Hooks. The initial purchase price is higher, but you need to look at the ownership costs over the few years you'll likely have them. The primary purpose of an aftermarket racing disc is to flow more air and run cooler. Heat is what is causing your issues in the first place. Nothing, and I do mean nothing, will hold up to a beating or flow air like our J Hook discs. Here are few of the big differences between the products:
Vane Count- AP Racing C7 Z51 J Hook discs have 72 vanes, vs. what appear to be 24-48 on the RB discs. More vanes increases airflow and disc face stability.
Our response:
Vane count for most brake manufacturers (including AP) is based on single count (ie. 48, 52, 72 etc.), however RB’s cooling vanes are variable between the inner and outer rotor edge (typically 36 inner and 54 outer) to optimize the cooling effect. The traditional single vane count is certainly not the primary factor for rotor cooling; the design of how to effectively cool the disc is what really "counts".
RB’s convergent vane design utilizes wide inlets and narrow outlets. Velocity of airflow increases as it enters through wide inlets, and exits through narrow outlets. Wider inlet can maximize the airflow at lower pressure, while its velocity decrease through (more) cooling vanes to absorb more heat from the disc before exiting to the outlet.
Conventional or competitions' "single vane count" design has a flaw in which due to the rotor outer diameter is larger than inner, so it ends up being "Divergent" vane which is opposite to optimizing the air flow for effective cooling per Bernoulli's principle illustrated below.
Benefits of the convergent vane design can be supported and better understood with review of Bernoulli’s convergent duct principle.
Bernoulli's theorem states: "When a gas or fluid is flowing through a convergent duct (as in nozzle stator vanes or venturi), its speed will increase and its temperature and pressure will decrease.”
t1 = Inlet air temperature
t2 = Outlet air temperature
Assume the air flow and inlet air temperature are constant, we want the outlet air temperature to be as high as possible to maximize the cooling effect.
RB's convergent vanes optimize the cooling effect not only can remove more heat and keep the disc cooler but result a more uniform disc temperature across the braking surface which is essential to keep the rotor from warping and cracking.
The advantage of RB two piece rotors last more than 20 track days and run 100-125 deg F cooler was officially recognized and reported by an NSX track racer in 2006.
I am eagerly awaiting the rest of y'all's response, in particular in regards to the reports of Racing Brake rotors separating from the hats. Thank you.
Racing Brake rotors vs AP Racing J hooks
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