BBK Comparison thread: Brembo vs. StopTech vs. AP Racing

[Mike]

Gary,
That new 355 mm rotor, will it work with my GT calipers? Also, do you have a rear one that will work with the stock caliper?

Also, part numbers for them please!

[Gary_C]

Originally Posted by Mike

Gary,
That new 355 mm rotor, will it work with my GT calipers? Also, do you have a rear one that will work with the stock caliper?

Also, part numbers for them please!

Mike,

Good news!

Yes, you can buy my 2pc. fully floating rotor assemblies and end up with what would be a COMPLETE Brembo Gran Turismo system.

I worked with engineering specifically to make this possible so that people have the option to start with the caliper upgrade,...and as they progress they can upgrade their system along the way.

More good news for other people unsure of where to start at;

You can start with the FRONT caliper upgrade...

...down the road, add the 2pc. rotors to complete the FULL GT Front system...

...and again down the road, add the REAR Brembo GT system.

Bias remains appropriate the entire way, and you can realize what each stage of these upgrades offers in terms of performance along the way. I am definitely a mod geek when it comes to my cars and I love the idea of doing things in stages and learning what exactly does what along the way.

[AP - Chris_B]

Originally Posted by Gary_C

Chris,
Do you know if AP tried to go after that OEM account as well?

As far as I can tell, AP Racing spends about zero effort in going after OE accounts from Detroit, although the marketing people at that level don't drop many hints. They do supply GM's Holden HSV programs in Australia, but AP are not really geared for high volume production. It's all been the specialty stuff like the newest cars from Arash, McLaren, Gumpert, Rossion, Lotus, Tramontana, GTA, Caparo, Plethore, etc. These are all low-volume, extreme supercars, not production vehicles like the 'Vette.

[vividracing]

+1 Gary This Thread Needs to be Thumbnailed!

[AP - Chris_B]

Originally Posted by imag

Basically everyone is asking us to trust them. That's fine, but it's different than most industries, where I can really research the products I want to buy. I'm not used to it.

Me neither. But over the 20 years I've been in this industry I've learned that reputations mean something. They are hard earned and quickly lost. I have also come to understand that I'm buying an experience, not a product. It's a bit like the guy who goes into a home improvement store to buy a drill. He really wants holes, not the drill!

Just because I may reason that one product is slightly better than another, the service after the sale can trump small differences in product offering. All it takes is some bad experiences with a company to undo any perceived product advantage.

Originally Posted by imag

One metric I referred to before that I would like to consider is weight. It obviously cannot be looked at in a vacuum, but it is a relevant data point, as we all realize the benefit of unsprung weight reduction. If each of the main BBKs are probably going to be fade-free for 30 minute sessions, lighter is better. I don't know if anyone has data on caliper/rotor weight for each of the BBKs, but it would be nice to have.

AP5700 (Front 6-piston kit with 362x32mm 2-piece disc) --

Caliper weight, unloaded: 7.3 lb. / 3.31 kg
Caliper weight, loaded w/pads: 10.4 lb / 4.72 kg
Pad area: 72.50 cm^2
Pad thickness: 16.8mm
Rotor weight, assembled: 20.3 lb. / 9.21 kg

Notes: This kit was developed to fit many 18" wheels for those who wish to have a larger selection of track tire compounds. The matching rear kit is strongly recommended for optimum mechanical and thermal brake bias.


AP3750 (Rear 4-piston kit with 330x25.4mm 2-piece disc) --

Caliper weight, unloaded: 4.7 lb. / 2.13 kg
Caliper weight, loaded w/pads: 6.7 lb. / 3.04 kg
Pad area: 48.62 cm^2
Pad thickness: 16.0mm
Rotor weight, assembled: 22.8 lb. / 10.3 kg (iron hat for long-life parking brake function)

Approval and backing by the legendary, record-breaking driver Steve Millen: Included in all AP Racing BBKs at no extra charge!

A note about bolted vs. floating kits. In our experience in designing and building aftermarket upgrade brake systems since 1990, bolted disc assemblies should be used wherever possible. The maintenance-free nature of this type of assembly clearly trumps any advantage of a floating assembly for most users. Only when the thermal capacity of the system is being tested regularly should a floating system be considered.

One drawback of floating systems on street vehicles is lack of proper maintenance. Race teams have a crew of mechanics that perform regular maintenance schedules, which includes an intense amount of brake servicing. For the street, we all just like to bolt them on and forget them. Floating disc assemblies, while definitely having distinct thermal expansion advantages in the upper temperature ranges, tend to collect brake dust, road grime, salt, etc., in between the bobbins and the hat. If cleaned out regularly, this poses few problems. However, most owners aren't up for the extra maintenance (or, more likely, aren't told about it by whoever sold them the kit). But if left to build up, this debris can actually start to prevent the disc from floating -- only now its location is not controlled.

Example: We have seen drivers who have stated their system performs normally when warm, but there is a pronounced steering wheel judder when left overnight. After driving for a bit, thermal expansion of the warmer rotors allowed the parts to become free again. Once hot, parking the vehicle leaves the iron disc just slightly out of plane with respect to the aluminum hat. During cool down, the disc "sticks" in this position due to debris and dust. Once warm again, the disc frees up and all is back to normal.

I am NOT saying this happens all the time with all floating kits! But I am saying it is an issue (like potential rattling sounds) that is entirely prevented when staying with a bolted disc assembly. Talk to anyone with an R35 GT-R who goes over speed bumps or into driveways and hears his car sound like someone bumped into a dishwasher full of large plates. The large discs on that car overpower the float springs and leave drivers sure they have suspension components loosening up!

My rule of thumb: Only go to a floating assembly when it is proven necessary. Several AP Racing systems are sold in a floating arrangement for such applications -- the G's and Z's haven't been two of them. We have done full-floating, dedicated track kits in the past and can continue to do so if the demand is there, but these are not really something most people want to live with on the street. You guys with dedicated track cars -- get in touch with us and we'll work something out. It's a little pricier, but you'll be glad you did.

A better solution? AP Racing's Strap Drive system is the best of both worlds. The disc and hat are free to expand as needed and move slightly relative to each other -- and there are no moving parts to rattle or trap debris. This system is limited in availability at the moment, but could find its way into more kits in 2010. If anyone is interested, that is...

Chris

[ChrisSlicks]

For reference the OEM front rotor is 29 pounds. I haven't weighed the rear, but I'm sure it is similar given only a slightly smaller diameter and have a larger hat.

I'm also interested in what Mike weights the stock calipers in at, when I had them unbolted they felt pretty hefty but I never got to weight them.

All I know is that these Akebono calipers are some of the worse OEM calipers on this class of car I've seen in a long time. They definitely went for the 95th percentile on this one.

[Gary_C]

Originally Posted by AP-Chris_B

A note about bolted vs. floating kits...

Here's a good example of a difference in opinion, most likely created by each companies various experiences over time, which ultimately lead to different solutions for their own products.

All of Brembo's 2pc. discs are full floating, specifically for the benefits they offer to performance, longevity, and safety...both on street and at the track.

Brembo uses a very unique float hardware that they developed and patented which specifically addresses many of the issues that Chris mentioned above. Despite the fact that the topics Chris mentioned above can be true in one form or another, it was a conscious decision by Brembo to develop a product expressly for the additional benefits, while focusing on eliminating any potential side affects.



Regardless of the type of usage, track or street, all metals expands with heat. Because of the fact that cast iron and aluminum also expand at different rates, it's important to allow the disc to have room to grow so that it doesn't stress the mounting points or hardware between the different materials. There are issues that affect the rate of fatigue when you join dissimilar materials and expose them to high stress applications. This is the exact reason that racing applications lead to the development of floating rotors, and away from fixed/bolted applications.

Cast iron by nature doesn't have the ductility to deform and return to it's original state which is why there is a higher chance of warpage and/or cracking when it is not allowed proper room for expansion. I personally do not recognize the "maintenance-free nature" of a fixed/bolted disc unless you are fully aware that you are not introducing the components to temperatures/expansion that exceed the natural elasticity of the materials used. Some companies simply recommend that you regularly inspect and re-torque the disc assemblies, others suggest that you safety wire each piece of hardware. A few specifically use steel hats/bells to bring the material likeness closer together, while some offer the opinion that the product is not ideal for excessive track use (which should also include aggressive street driving that can create nearly identical peak temperatures).

Again, an example of a difference in opinions based on each of our personal experiences. I just wanted to share that the Brembo float hardware does off the best of both worlds with none of the issues previously mentioned.

[Mike]

Factory sport calipers:
Front
11.0 bare, 13.0 with pads
Rear
5.6 bare, 7.0 with pads

[AP - Chris_B]

Originally Posted by gary_c

Regardless of the type of usage, track or street, all metals expands with heat. Because of the fact that cast iron and aluminum also expand at different rates, it's important to allow the disc to have room to grow so that it doesn't stress the mounting points or hardware between the different materials. There are issues that affect the rate of fatigue when you join dissimilar materials and expose them to high stress applications. This is the exact reason that racing applications lead to the development of floating rotors, and away from fixed/bolted applications.

Gary and I agree that for racing applications, floating disc assemblies are preferred for the many advantages they offer. Brembo has done a good job over the years mitigating the side effects for the street, with the GT-R being one notable exception. Others have used floating discs in an attempt to hide poor metallurgy, sub-standard engineering or lack of testing. To modify an old phrase: If you don't know, float it!

But for most mortals that keep bulk disc temperatures below 1150°F or so, we have found that floating discs are not required or even desired in many cases. This applies to almost all street guys and most beginner to intermediate track guys. In fact for many kits, the downside outweighs the benefits since the advantages don't even come in to play at lower temps. Note: I am only saying this under the assumption that high quality materials and workmanship are used throughout. Brake systems that spend time over 1150°F would benefit from floating discs more than the drawbacks. These are the faster intermediate and advanced drivers or those that, for whatever reason, are just harder on their equipment than most. Anyone who tracks their car should be at least using temperature paints on the OD of the disc so they know what temps their brakes are seeing. This is imperative for pad selection and the common discovery that better cooling might be a good idea.

Originally Posted by gary_c

Cast iron by nature doesn't have the ductility to deform and return to it's original state which is why there is a higher chance of warpage and/or cracking when it is not allowed proper room for expansion. I personally do not recognize the "maintenance-free nature" of a fixed/bolted disc unless you are fully aware that you are not introducing the components to temperatures/expansion that exceed the natural elasticity of the materials used. Some companies simply recommend that you regularly inspect and re-torque the disc assemblies, others suggest that you safety wire each piece of hardware.

Cast iron is a less ductile material than aluminum, for sure, but it certainly expands and contracts during thermal cycles. The trouble begins if it is operated beyond its plasticity region. It doesn't much matter if the disc is bolted or floating, once taken beyond the plastic part of the stress-strain curve, the material is screwed. Floating disc assemblies do hide problems better as they decouple the disc from the hat, but the problem is still there if it ever starts.

The most common mode of failure for bolted disc assemblies is coning, or the out-of-plane distortion that occurs when a very hot iron disc is trying to expand due to temperature and high rotational speed, but is held on only one side by the hat. While the aluminum hat does give a bit for the iron, at a certain point, a combination of temperature and speed, it is not enough. This is the primary issue that floating discs address (among a few others). Yet it only occurs under extreme use and extreme temperatures, approaching race usage. Again, full-on racing brake systems are different for a variety of reasons. Not all of the solutions found on the track could or should be used in brake systems primarily meant for the street, but a lot of advances to come from racing. Anyone who has tried race pads and full-floating rotors on the street (and lived to tell about it) knows exactly what I'm talking about!

This is where I usually hear, "Great Chris, just cut to the damn chase and tell us if floating discs are better than bolted!" OK, here's my answer, "Yes. And no. And sometimes. It depends on what they are being used for." Now isn't THAT helpful?

Since we're on the topic, I do not agree at all with those companies (not Gary's) that tout they race on the same exact equipment they sell to the street guys. This leads to either an under-performing race setup or an overly compromised street system. When comparing both applications, there are certain requirements that are diametrically opposed and that is why both AP Racing and Brembo use different equipment for each. If you compare a professional racing brake system to even the highest-priced street systems, you will find a significant price difference (sometimes 2-3x!). Some of the most advanced systems cost over $30k per car, not including pads, lines, fluid, hardware, etc. That should tell you a lot about the differences.

And for those that might be reading this and wondering, we would NEVER, EVER recommend re-torquing an AP Racing disc assembly. These are carefully torqued during assembly to a prescribed value that takes thermal expansion into account. The #1 cause of broken hardware is an over-eager, but well-meaning, mechanic torquing the nuts to a value that might be considered "normal" for a 1/4-28 steel fastener (usually 85-90% of yield strength). Then when everything gets hot and starts to expand, the bolt is stretched beyond its limit and either loosens up or fails outright. Either of which is a recipe for disaster!

Chris

[Mike]

Originally Posted by AP - Chris_B

And for those that might be reading this and wondering, we would NEVER, EVER recommend re-torquing an AP Racing disc assembly. These are carefully torqued during assembly to a prescribed value that takes thermal expansion into account. The #1 cause of broken hardware is an over-eager, but well-meaning, mechanic torquing the nuts to a value that might be considered "normal" for a 1/4-28 steel fastener (usually 85-90% of yield strength). Then when everything gets hot and starts to expand, the bolt is stretched beyond its limit and either loosens up or fails outright. Either of which is a recipe for disaster!

Chris

Thank you so much for that little nugget of info! My powdercoating business focuses on brake calipers. I've done 2 sets of rotor hats for AP racing setups on the 350Z. Fortunately, they were both show cars and the brakes will probably never even get warm, but I now will not do them at all, or just mask the rest of the rotor if I do and leave them assembled.

When the ring wears out do they have to buy a whole new assembly? Or send them in to have them re-ringed?

[AP - Chris_B]

Originally Posted by Mike

When the ring wears out do they have to buy a whole new assembly? Or send them in to have them re-ringed?

The iron outer rings are are sold separately and can easily be replaced by a qualified mechanic (or an experienced DIY'er that is methodical about reading instructions). New hardware should always be used so the torque values are accurate with the new discs.

BTW, powder coating hats that are bolted to discs does not present a huge problem, although I wouldn't do it on a car I was taking to the track. I would not recommend powder coating floating hats as the clearances would change too much with the added thickness of the paint. Depending on which type of float hardware is being used, you might not even be able the get bobbins back into the slots!

Chris

[Mike]

I don't offer any powdercoating for cars that see the track. I do ceramic coat the hats on solid rotors, as that holds up much better and still prevents rust. And I do powdercoat my own calipers that see track duty, but thats because I can redo them whenever I want.

[imag]

Chris and Gary: thank you. I hope I didn't start anything, but the comments from both sides are pretty epic for a forum. You have outdone yourself.

I looks like the weight is just not a deciding factor; it's too close to really be relevant. Thanks for listing them though. There are some other things that have gotten my attention, but I will leave it to each person on here to judge on their own. I can see a few pros and cons either way, but I would say that you both more than justified AP and Brembo kits for this car. It might sound dumb, but I actually feel honored that you both took time to give us this much detail.

Anyway, I'm happy. Now I just need to wait for my bonus to get mine on order...

Chris - I am curious. Why does the iron hat on the rears help the parking brake function?

[AP - Chris_B]

Originally Posted by imag

Chris - I am curious. Why does the iron hat on the rears help the parking brake function?

Vehicles that have a drum-in-hat (DIH) mechanism for a parking brake, like most Nissans do, rely on the hat portion to stand up to the load put on them by the brake shoes. There a hill-holding requirement in some U.S. states that test for this as part of an annual inspection. And, some people actually use the parking brake to help rotate the car in slow corners. I know it is hard to believe and I'm sure you have never personally done this (), but it has been known to happen.

Although lighter, aluminum would not survive nearly as well over time in this environment. The first issue is abrasion from the shoes once any plating wore through. The second is the possibility of the parking brake being set after hot lapping (I suggest never doing this regardless of hat material). If done, there is a good chance that a very hot aluminum hat would distort and go out of round. Iron hats don't suffer the same fate as they pretty much last forever. There are some cars for which aluminum rear hats make sense, but the Nissans did not meet all of our qualifications for such.

Chris

[imag]

Originally Posted by AP - Chris_B

Vehicles that have a drum-in-hat (DIH) mechanism for a parking brake, like most Nissans do, rely on the hat portion to stand up to the load put on them by the brake shoes. There a hill-holding requirement in some U.S. states that test for this as part of an annual inspection. And, some people actually use the parking brake to help rotate the car in slow corners. I know it is hard to believe and I'm sure you have never personally done this (), but it has been known to happen.

Although lighter, aluminum would not survive nearly as well over time in this environment. The first issue is abrasion from the shoes once any plating wore through. The second is the possibility of the parking brake being set after hot lapping (I suggest never doing this regardless of hat material). If done, there is a good chance that a very hot aluminum hat would distort and go out of round. Iron hats don't suffer the same fate as they pretty much last forever. There are some cars for which aluminum rear hats make sense, but the Nissans did not meet all of our qualifications for such.

Chris

That makes sense... thanks!

And of course I never e-braked turns in my first car, an '86 Ford Taurus, in parking lots at night. The tricky thing about that car was that it had a foot brake, which is not easy to feather when you're trying to steer and hold the release out at the same time. Not that I would know...

I would also never use the e-brake when a cop is coming up on me, but it's good to know I could continue to not do that if I got an AP kit.