Uneven wear with AP Racing Sprint BBK

[Sleepless]

Originally Posted by wparsons

That would be activating the rear brakes most likely though, and unless you're driving on an oval should be pretty even left to right.

No, it definitely affects the brake activation in the front.

[JRitt]

Have you run any tracks other than Road Atlanta...maybe one with more brake zones leading into left-hand turns?

I spied your coilovers in your first pic. Was your car corner-balanced taking driver weight into account when you installed the suspension? What is the weight split on the front left to right?

Have you taken disc or caliper temperatures on both front corners with a pyrometer or temperature strips?

Is your duct setup the same on both front sides?

What does your tire wear look like on the driver front vs. the passenger front?

Nothing you wrote sounds like a brake hardware issue to me. As mentioned by CSG, brake calipers and discs are a rather 'dumb' system. That said, the electronic braking/traction nannies can be really messy. We see it all the time with systems that are on or partially turned off, etc. They try to vector the car by applying the brakes, which leads to all sorts of wear that one wouldn't logically expect.

It definitely sounds like your driver front is running hotter than the passenger side front. We need to understand why that is happening, and I don't believe the answer is in the calipers or discs. My hunch is that you're weight balance, alignment, track configuration, trail-braking technique, etc. are all potentially contributing towards getting more weight transferred up and over the driver front wheel, which is taxing the brakes on that side to a greater extent than on the passenger side.

My advice would be to first get some good temperature data to see just how dramatic the difference between the left and right fronts actually is. I'd also love to see those corner weights and your tire wear on both sides. With all of that data in hand you can paint a better picture of what's going on with the car as it gets into braking zones.

My BRZ is NA. The Sprint kit is advertised as sufficient for much heavier, higher power cars. I do brake HARD as you can see in my videos, but I can't imagine that my 200whp 2700 lb car is exceeding the Sprint kit's capacity.

Yes we do have faster more powerful cars running similar kits without issue, and no I don't believe you're exceeding the Sprint Kit's capacity. "Exceeding capacity" would mean that you are running the kit so hot that you're experiencing significant pad or fluid fade. My understanding is that you're not experiencing either, and it sounds like you're actually enjoying the brake kit overall. You're simply wearing through consumables faster than you'd ideally like to be, and the wear appears a bit wonky.

I've talked about this on this forum before, but in professional racing, parts are designed to make it to the end of the race. Then they're basically free to explode, melt, or spontaneously combust. If they last significantly longer than the end of the race, then they were overbuilt, too heavy, etc. Obviously we try to give our aftermarket customers a balance in this area. We know that nobody wants a brake system that will barely make it through a track day, and we'd never design such a product. We want the kit to perform fade-free under the conditions in which they're driving, providing a safe and confidence-inspiring experience in the process. Some people will however require a little extra 'fat' built in. They'll want to change pads and discs less, bleed less often, etc., and they're willing to deal with a little extra weight in exchange for that convenience. For those customers we have the Endurance Kit.

Obviously nobody really knows until they thrash the system if it is best for their scenario. After collecting as much data as possible, we may ultimately find that the Endurance Kit truly is the better choice for your situation if you want to go longer between servicing the brakes. Or, we may find that you're carrying far more weight on the driver front corner when you get into brake zones...or find that the brakes wear perfectly even at a different track. Don't worry though, we'll do our best to try and help you determine that, and to get you where you want to be.

[gramicci101]

Originally Posted by JRitt

brake info

Jeff,

The calipers are the same between the kits, but are the rotor hats? If they are, all that would be necessary to upgrade was new discs and new brackets, right? What would the taller disc do to front/rear brake bias?

[ls1ac]

I am an old guy and like KISS (keep it simple stupid) approach. A small amount of leading edge wear is not unusual. Yours is more than normal. Traditionally this is caused by a poor surface on the disk. This dose not have to be large imperfections, it can be microscopic surface characteristics that can be caused buy heating and cooling over time. These are castings that are finished machined not machined from a solid piece of steel. swap right to left and see if the problem follows the disk.

[mrk1]

JRitt makes a good point about looking at tire wear, maybe find something external from the brakes thats making one side work harder. Also looks to me like your getting to fast for the brakes haha

[ATL BRZ]

Originally Posted by JRitt

Have you run any tracks other than Road Atlanta...maybe one with more brake zones leading into left-hand turns?

I've run one counterclockwise track, Atlanta Motor Speedway (roval), and Barber MSP a few times as well since installing the BBK. Road Atlanta turn 5 and 10A are left handers that are very very heavy on brakes.

Originally Posted by JRitt

Have you taken disc or caliper temperatures on both front corners with a pyrometer or temperature strips?

No, I don't have those.

Originally Posted by JRitt

Is your duct setup the same on both front sides?

Yes, I'm running the 997 GT3 brake air guides on both sides



...that mount to the control arms in the same fashion they do on the GT3, only using zip ties for security



Myself and several others who are running them believe they are functional at drawing in air from the wheel wells at speed and redirecting it to the rotors.

Originally Posted by JRitt

What does your tire wear look like on the driver front vs. the passenger front?

At Road Atlanta and Barber it does appear that my left front tire gets worn a bit more than others but I constantly rotate them and I've gotten pretty even wear on all 4 by doing so after every other event.

Originally Posted by JRitt

Nothing you wrote sounds like a brake hardware issue to me. As mentioned by CSG, brake calipers and discs are a rather 'dumb' system. That said, the electronic braking/traction nannies can be really messy. We see it all the time with systems that are on or partially turned off, etc. They try to vector the car by applying the brakes, which leads to all sorts of wear that one wouldn't logically expect.

It definitely sounds like your driver front is running hotter than the passenger side front. We need to understand why that is happening, and I don't believe the answer is in the calipers or discs. My hunch is that you're weight balance, alignment, track configuration, trail-braking technique, etc. are all potentially contributing towards getting more weight transferred up and over the driver front wheel, which is taxing the brakes on that side to a greater extent than on the passenger side.

My advice would be to first get some good temperature data to see just how dramatic the difference between the left and right fronts actually is. I'd also love to see those corner weights and your tire wear on both sides. With all of that data in hand you can paint a better picture of what's going on with the car as it gets into braking zones.

Yes we do have faster more powerful cars running similar kits without issue, and no I don't believe you're exceeding the Sprint Kit's capacity. "Exceeding capacity" would mean that you are running the kit so hot that you're experiencing significant pad or fluid fade. My understanding is that you're not experiencing either, and it sounds like you're actually enjoying the brake kit overall. You're simply wearing through consumables faster than you'd ideally like to be, and the wear appears a bit wonky.

I've talked about this on this forum before, but in professional racing, parts are designed to make it to the end of the race. Then they're basically free to explode, melt, or spontaneously combust. If they last significantly longer than the end of the race, then they were overbuilt, too heavy, etc. Obviously we try to give our aftermarket customers a balance in this area. We know that nobody wants a brake system that will barely make it through a track day, and we'd never design such a product. We want the kit to perform fade-free under the conditions in which they're driving, providing a safe and confidence-inspiring experience in the process. Some people will however require a little extra 'fat' built in. They'll want to change pads and discs less, bleed less often, etc., and they're willing to deal with a little extra weight in exchange for that convenience. For those customers we have the Endurance Kit.

Obviously nobody really knows until they thrash the system if it is best for their scenario. After collecting as much data as possible, we may ultimately find that the Endurance Kit truly is the better choice for your situation if you want to go longer between servicing the brakes. Or, we may find that you're carrying far more weight on the driver front corner when you get into brake zones...or find that the brakes wear perfectly even at a different track. Don't worry though, we'll do our best to try and help you determine that, and to get you where you want to be.

Thanks for the advice and willingness to help me. After speaking with a few other helpful and knowledgeable people last night, I have a plan of attack after replacing the rotors.

-Get the car realigned and possibly corner balanced
-Get some datalogging going (Aim Solo DL) and share the logs with the knowledgeable folks here
-Get temp strips and/or pyrometer and check temps on hot pits
-Start doing the pedal dance religiously (get the 86Nanny pedal dance device once its available)
-Adjust my braking method to brake slightly earlier into faster corners and see how that affects my times
-Look in to revisiting brake ducting to get some extra air to the rotors
-Last resort would be the Endurance kit upgrade. Questions on that: Would I keep my calipers and just get a different mounting bracket and Endurance rotors and pads that would be it? Would the Endurance kit fit under my Mach V Awesome wheels?

Again I really appreciate the response and I am still happy with my BBK and the way it performs on track. I hope that if anyone else is experiencing the uneven wear that they'll speak up about it so we can come together and find the root cause of the issue.

I'll try to keep this thread updated with my findings. It may be a month or so before I start cracking away at this as I have some other financial obligations to take care of first.

[CSG Mike]

Originally Posted by ATL BRZ

-Last resort would be the Endurance kit upgrade. Questions on that: Would I keep my calipers and just get a different mounting bracket and Endurance rotors and pads that would be it? Would the Endurance kit fit under my Mach V Awesome wheels?

For the price of new brackets, hats, and rotors, you'll be better off getting a new Endurance kit, and selling your Sprint kit. The only components you'd be keeping are the lines and calipers.

Also, the Endurance kit has built-in brake duct air guides

[JRitt]

IMO, those GT3 brake ducts aren't likely doing a whole lot for you. More and more cars these days have that sort of plastic piece on the undertray. The C7 Corvette Stingray is another good example. Realistically however, for brake ducts to be moderately effective, the air needs to be dumped directly into the area where that air is needed. Otherwise the air is just diffused...it spills all over the place. In your case, you need cooling air in the center of the disc flowing into the vanes. Otherwise, most of the air isn't reaching its intended target. Please see the pic of our Endurance Kit integrated duct below. That is what a proper duct termination at the disc end looks like. The air only goes where it is supposed to go, and there's not really anywhere else for the air to go:

Thanks for the advice and willingness to help me. After speaking with a few other helpful and knowledgeable people last night, I have a plan of attack after replacing the rotors.

-Get the car realigned and possibly corner balanced
-Get some datalogging going (Aim Solo DL) and share the logs with the knowledgeable folks here
-Get temp strips and/or pyrometer and check temps on hot pits
-Start doing the pedal dance religiously (get the 86Nanny pedal dance device once its available)
-Adjust my braking method to brake slightly earlier into faster corners and see how that affects my times
-Look in to revisiting brake ducting to get some extra air to the rotors
-Last resort would be the Endurance kit upgrade. Questions on that: Would I keep my calipers and just get a different mounting bracket and Endurance rotors and pads that would be it? Would the Endurance kit fit under my Mach V Awesome wheels?

Again I really appreciate the response and I am still happy with my BBK and the way it performs on track. I hope that if anyone else is experiencing the uneven wear that they'll speak up about it so we can come together and find the root cause of the issue.

I'll try to keep this thread updated with my findings. It may be a month or so before I start cracking away at this as I have some other financial obligations to take care of first.

No worries...That's what we're here for!

That looks like a good/logical plan of attack. I have a feeling that addressing your corner weight and alignment will not only make your car handle substantially better, it will help even out your brake and tire wear. That alone should save you money and time in the long haul. On all of my track cars over the years (Integra Type R, miata, Z06, and 350Z), it was unbelievable what a proper setup from a legit race shop did to the handling. I believe it's money very well spent. You won't have to fight the car to do what you want it to do, you'll dramatically decrease your steering input in many situations, you won't have to throw it into certain turns, or rely on brakes to get it rotating...the list goes on. Just make sure you have the car configured as closely as possible to the actual condition it will be when you're driving it in on the track (your weight in the driver seat, half tank of gas, etc.).

As for going to the Endurance Kit, I agree that should be your last resort. Frankly, I don't think you'll need to go that route once you have the car properly sorted. If you do end up going that route, your best bet is to sell your complete Sprint Kit on the used market and start fresh. The cost of the components individually is greater than the cost of the entire kit. Just contact me if it comes to that I'll do what I can to help you out.

On wheel fitment I have the Mach V Awesome 17x9 as a confirmed wheel fitment without a spacer, but I don't know the offset. Someone on this forum has tried it successfully though. You can always check the template to be 100% certain.

You probably aren't going to see a ton of posts about odd wear rates from other owners. We've sold many hundreds of these kits over the past few years, and the only time we typically hear from our customers is when they buy fresh pads and discs or win an event. Very few of them are having any problems, and the AP Racing hardware tends to be fairly bulletproof. Every once in a great while there are some minor malfunctions after the parts have been flogged unmercifully on the track for long enough, but it's nearly unheard of to have a manufacturing defect, etc.

Anyway, keep us in the loop. I'll be curious to see the results as you work down your list. Again, I think getting the car setup properly is going to pay big dividends for you. The car should feel a lot more planted and stable under just about all conditions, and particularly so in brake zones.

ps I forgot to say...I had my Miata set up with no passenger seat in the car and my body weight in the driver seat (roughly 200 lbs). When I put the passenger seat in and had a 200 lb. passenger, it was unbelievable how much worse the car felt! The thing didn't want to turn worth a darn (relatively speaking). I think on lightweight, low power cars like we have, the car is particular sensitive to changes. You don't have big power, big fat tires with huge mechanical grip, etc. to overcome any flaws. You lose speed and it takes you forever to claw it back!

[ATL BRZ]

So I ordered new rotors on 4/2 from CSG (drop shipped form Essex)

They finally shipped today after learning the purchase order was left open all month without any further processing or recognition and my rotors have been sitting on the shelf at Essex.

Track day on Saturday to hopefully pedal dance and modulate my brakes away from this issue.

[heeltoe86]

I'll add to this since I'm on the opposite coast and have experienced this for myself. (Vegas really, but lately I've been driving to SoCal for 86Cup events) Like the OP I have experienced brake pad taper and equate it more towards not being able to do the pedal dance because of inadequate time for vehicle warm up. I've noticed if not done, and trail braking that the traction light will come on while trail braking into most corners. After a few hot lapping sessions without pedal dance I would end up with pad taper on the loaded front wheel. With pedal dance done properly I wouldn't have the traction light flash while trail braking and obviously brake pad wears more even. CSGMike and David have been a tremendous help with my braking issues. I used to do 3-4 events on a set of race pads like XP10s, ClubRacers on stock calipers. Now with the Sprint kit I've been seeing 8 events on my most recent pads PMu 999s. It is integral to pad life to make sure the pedal dance is done especially for more advanced drivers. This mostly relates to HPDEs and time trials. I have yet to pull the ABS fuse to see how the car really reacts to analog braking. I hope this sheds some more light into the matter.

[86Nanny]

Originally Posted by heeltoe86

I'll add to this since I'm on the opposite coast and have experienced this for myself. (Vegas really, but lately I've been driving to SoCal for 86Cup events) Like the OP I have experienced brake pad taper and equate it more towards not being able to do the pedal dance because of inadequate time for vehicle warm up. I've noticed if not done, and trail braking that the traction light will come on while trail braking into most corners. After a few hot lapping sessions without pedal dance I would end up with pad taper on the loaded front wheel. With pedal dance done properly I wouldn't have the traction light flash while trail braking and obviously brake pad wears more even. CSGMike and David have been a tremendous help with my braking issues. I used to do 3-4 events on a set of race pads like XP10s, ClubRacers on stock calipers. Now with the Sprint kit I've been seeing 8 events on my most recent pads PMu 999s. It is integral to pad life to make sure the pedal dance is done especially for more advanced drivers. This mostly relates to HPDEs and time trials. I have yet to pull the ABS fuse to see how the car really reacts to analog braking. I hope this sheds some more light into the matter.

@heeltoe86 I'd be interested in hearing your report with no ABS. That's IF you don't mind sharing once you've tested with the fuse pulled. I expanded my device from pedal dance with a button push to also controlling ABS as well for drifters in mind. I have a unit testing at round 2 of lone star drift this weekend, but the more data the better.

[philooo]

any update on this ?

[puma]

i just found this thread, all i can bring to the table is that removing the ABS fuse without removing the ABS itself is a really bad idea, you end up with a really f&?ked up bias and you end up with basically no rear brakes


When we first tried it (actually was a mistake, i removed a lot of wiring and seems like i messes to much with ABS) the brakes were horrible so we made a patch to remove the ABS. Then we eneded up with too much rear brakes but it could be fixed with a rear adjustement bias valve or using stronger pads in front.





than we decided we needed a balance bar but didn't want to install a whole pedals kit assembly so we installed that thing and i feel this is the only way to run without the ABS in this car.

[86Nanny]

Interesting find @puma I've been tackling the ABS topic with several of my test drivers for the sake of pleasing drifters who need ABS off to maintain drifts, or track guys who want to escape quick footed "ice mode" / just don't like ABS.

My target hasn't been as in depth as yours since I'm controlling everything over the ECU nodes, but what we've managed so far is ABS disabled without pulling the fuse (button press), zero wire pulling and report of zero bias changes.

Pretty certain I can help you out, so feel free to shoot me a message or email me beastronix@gmail.com

Originally Posted by puma

i just found this thread, all i can bring to the table is that removing the ABS fuse without removing the ABS itself is a really bad idea, you end up with a really f&?ked up bias and you end up with basically no rear brakes


When we first tried it (actually was a mistake, i removed a lot of wiring and seems like i messes to much with ABS) the brakes were horrible so we made a patch to remove the ABS. Then we eneded up with too much rear brakes but it could be fixed with a rear adjustement bias valve or using stronger pads in front.





than we decided we needed a balance bar but didn't want to install a whole pedals kit assembly so we installed that thing and i feel this is the only way to run without the ABS in this car.