BRZ STi?

[dpfarr]

Further more, I submit my ts was the deal of the century.

[Irace86.2.0]

Originally Posted by ZDan

Preface this by saying that I have worked with Brembo in Italy, Continental (Teves) in Germany, and with J.Juan in Barcelona developing brake and ABS systems for 2-wheelers. Structural engineer but at this job I was also responsible for general vehicle development including brake performance.
Anyhoo...

Yeah, main reason is the moment due to pad/rotor friction acts to load up the leading edge of the pad and unload the trailing edge. You will usually balance this with a smaller-diameter leading piston to get more even pressure between pad and rotor along pad length. It's really not a huge deal though. I did notice a *slight* front-to-rear taper wear when I changed out my track pads, but very slight and of course can be fixed by swapping inside/outside pads next install.

They may tout them as "radial mounted", but how is that bracket mounted to the upright? Axial bolts. Actually this setup is marginally *less* stiff as you have an extra bolted joint (the "radial mount" part) in addition to the factory axial mount bolts.

For overall bolted-up caliper asembly stiffness, I would bet on the factory PP setup...

Besides uneven wear, there will be uneven pad contact that will reduce brake performance. I don't know by how much, but it will likely get worse and worse as the pad wears, especially if someone isn't rotating their pads like you mentioned. The STI rotors are staggered, even if they are axially mounted.



I think you mean it has an increased opportunity for flexion or failure if it wasn't secured properly. It should be stiffer. Think of it like a welded joint, which is stronger than the material it is joining, yet it has an increased opportunity for failure if poorly done. Similarly, the steel bolts running through the materials should make for a strong union. Moreover, the positioning is better, and the materials are stronger.

You will notice that the Brembo brakes on the PP use a small spacer between the caliper and the axle, which creates a smaller contact patch and a greater moment arm. These brakes appear to be cast, so the long body of the caliper creates an opportunity for deflection.



Compare that to the GT kit or the Wilwood kit. You say that the kit is axial mounted, so there is no difference, but then I would counter, what is the difference between a two piece axle versus a single piece if strength is maintained? In the case for these two kits, the bracket appears to be forged and machined, and it is fairly thick. It also centers the caliper over the rotor, and in the case of the Wilwood kit, uses protrusions that center the caliper like dowel pins. Lastly, the calipers on both of these kits are forged instead of cast, so for all of these reasons, I believe they are much stronger and more secured in position.

The Brembos on the PP are pretty bulky though, so perhaps that makes up for their shortcomings. Obviously, the bulk was necessary for some reason, and it makes for a smaller capacity for pad thickness.




Again, the point isn't to say the Brembo brakes are terrible. They are an upgrade, but there are aftermarket ones that are an upgrade from them for a similar investment for some. If you can do the labor like myself and sell your old brakes, the price is pretty good for what you can get. Regardless, the point of all this was just to provide a different perspective that the PP may not be the deal of the century. I'm glad that people are happy with their purchase, and I am not trying to change that, but it is healthy to have a realistic perspective on the situation--just saying.

[ZDan]

Originally Posted by Irace86.2.0

Besides uneven wear, there will be uneven pad contact that will reduce brake performance. I don't know by how much,

Pad contact will be maintained across the pad, there'll just be a bit less pressure at the front of the pad vs. rear. No loss of braking performance, just *slightly* front-to-rear tapered wear (under hard track usage) as the front of the pad is applied to the rotor with slightly greater pressure.

It really isn't that big a deal... Particularly considering that the car is fairly over-braked vs its power and weight.

but it will likely get worse and worse as the pad wears, especially if someone isn't rotating their pads like you mentioned. The STI rotors are staggered, even if they are axially mounted.

I'm getting *slightly* tapered front/rear pad wear. Of course it'll get "worse" but it's not a big deal. If I didn't take them out and rotate, might cost me ~10% of pad life I would estimate.

I think you mean it has an increased opportunity for flexion or failure if it wasn't secured properly. It should be stiffer. Think of it like a welded joint, which is stronger than the material it is joining, yet it has an increased opportunity for failure if poorly done.

You could consider that "radial" mount portion rigid, and you'll still have the same two *axial* bolted joints connecting your brake caliper bracket to the factory upright. Hence, you aren't getting the benefit of a TRUE radial-mount caliper. You're still axially mounted, you just have an additional joint to a not particularly stiff-looking bracket design with "radially" oriented bolts.

Similarly, the steel bolts running through the materials should make for a strong union.

Strong enough I'm sure, but not infinitely stiff. It's an additional bolted joint with additional flexure/compiance

Moreover, the positioning is better, and the materials are stronger.

How is positioning "better"? Your bracket bolts up to the upright at the factory positions. Those axial bolted joints will have the same (worse actually given the bracket design) flexure/compliance as stock.

You will notice that the Brembo brakes on the PP use a small spacer between the caliper and the axle, which creates a smaller contact patch and a greater moment arm.

That doesn't go between the caliper and upright, it goes behind the upright. I.e. it does not increase moment arm. Basically it increases stiffness of the upright and allows for a longer bolt so that bolt preload isn't as affected by temperature changes.


"Contact Patch", is going to effectively be a diameter of about 2x bolt diameter. But speaking of which instead of having broad beefy continuous cross-sections of material between mounts to the upright, you have an *additional* two small area bolted joints with the Wilwood and aftermarket Brembo GT calipers. Less stiff, more flexure. Of course they're made this way so they can be fitted to multiple different cars. But it *is* a design compromise that reduces stiffness.

These brakes appear to be cast, so the long body of the caliper creates an opportunity for deflection.

Cast 356-T6 aluminum is as stiff (slighlty stiffer) as machined 6061-T6. 10.5 Msi vs. 10.0 Msi modulus of elasticity. That's not an issue. What is is the structural path between the mount to the upright and the caliper. The aftermarket Wilwood and Brembo GT calipers have the additional bracket and bolted joints, there's less beefy continuous contiguous aluminum cross-section between the mounts to the upright and the caliper body. They're gonna be less stiff.

Compare that to the GT kit or the Wilwood kit. You say that the kit is axial mounted, so there is no difference, but then I would counter, what is the difference between a two piece axle versus a single piece if strength is maintained? In the case for these two kits, the bracket appears to be forged and machined, and it is fairly thick.

See above. Forged aluminum isn't stiffer than cast. Bracket isn't that beefy really, and it has a hard 90degree "hinge" built into it. Additional bolted joints with limited effective contact area, vs factory setup which has broad continuous large-cross-sections of material.

It also centers the caliper over the rotor, and in the case of the Wilwood kit, uses protrusions that center the caliper like dowel pins.

Which factory doesn't need because it doesn't have these additional bolted joints. Factory and aftermarket will have the same positional tolerancing due to clearance at the axial mounting holes.

Lastly, the calipers on both of these kits are forged instead of cast, so for all of these reasons, I believe they are much stronger and more secured in position.

These are gonna be stiffness-critical designs, not strength. Cast aluminum vs. forged have the same modulus, same material stiffness. But the factory part is gonna be stiffer as-mounted for the reasons already covered.

The Brembos on the PP are pretty bulky though, so perhaps that makes up for their shortcomings. Obviously, the bulk was necessary for some reason, and it makes for a smaller capacity for pad thickness.

Bigger opening = less stiffness. If you're going endurance racing you might want a wider opening and thicker pads.

Again, the point isn't to say the Brembo brakes are terrible. They are an upgrade, but there are aftermarket ones that are an upgrade from them for a similar investment for some. If you can do the labor like myself and sell your old brakes, the price is pretty good for what you can get. Regardless, the point of all this was just to provide a different perspective that the PP may not be the deal of the century. I'm glad that people are happy with their purchase, and I am not trying to change that, but it is healthy to have a realistic perspective on the situation--just saying.

Absolutely! Here, the OEM solution has some inherent advantages due to not requiring a separate bracket and additional two bolted joints between the caliper and the upright.

Is it really that big a deal? Probably not given that all of these systems are IMO massive overkill for this car at stock power. But for sure the "radial-mount" feature is not a benefit over stock when they both bolt up axially to the uprights. The "radial mount" part just keeps it from being even more of a stiffness reduction.

Honestly, the factory PP Brembo brakes are IMO massive overkill for this car at stock power. When I first learned they were going to be offered in I figured they'd be part of a $3500+ "package" and I was gonna skip it, because I know I could get pads and fluid that will work with the "base" brakes. For $1200, though, it's WELL worth it to me for:
1. ease of pad changes
2. improved braking feel
3. greater range of pad materials will work
4. less frequent fluid changes required
5. looks cool...

A bargain...

[gen3v8]

So we have not seen the PP brakes on the latest gen BRZ. Maybe they will be an even more Overkill. Like the Flouro 18+ WRX STI 6piston 340mm units with rears being similar size to the PP fronts

[Irace86.2.0]

Originally Posted by ZDan

A bargain...

I'll have to agree to disagree at this point. The Brembo GT kit is a significant upgrade over the OEM Brembo kit. The only reason the GT series can be cheaper than the stock brakes are because they are designed to work across multiple platforms verses the OEM kit. Guaranteed the forged calipers and bracket will make a difference. Guaranteed the larger pad thickness with handle heat better and have longer wear, and the GT kit will have more pad options. Guaranteed the staggered pistons will lead to better pad bite and contact, better pad wear and better performance.

It was nice to have a factory option, and they priced it fairly. The best part about these brakes is actually the resale value on the used market is actually pretty good because people see Brembo and think Brembo = Brembo across the board, so if anyone decides to upgrade down the road, these Brembos hold their value. I see them selling for $1500-2000. I can't recall what I sold my brakes for, but I think I paid around $1600 for my front and rear Wilwood BBK after selling my stock components. I'm sure someone could do better with their stock Brembos, but then they also paid more for them, yet in the end, I'm sure they could do better than $1600.

[Willpower]

You boys have gotten to the place where you are talking waaaaay over my pay grade on brake systems for cars haha! Now if you want to discuss treatment for stubborn supraspinatus tendinitis, novel manual therapy techniques for the arthrofibrotic knee following total knee arthroplasty, or the effects of high amplitude therapeutic exercise on the functional mobility of folks with Parkinson’s disease, well then I can wade back in with some expertise anyway.

ZDan: Damn. You go boy!
Irace86: Smart and stubborn modifier of NICE cars, I have just one more message...
DEAL OF THE CENTURY BABY!!!

Wishing you both Happy and Safe Holidays!

[ZDan]

Originally Posted by Irace86.2.0

I'll have to agree to disagree at this point. The Brembo GT kit is a significant upgrade over the OEM Brembo kit.

Um, nah...

Guaranteed the forged calipers and bracket will make a difference.

Not that forged material offers any real advantage in this application, but the GT calipers for the BRZ for sure look to me to be *cast*, I see draft angles and more blended radii vs. typical machined calipers with no draft and visible abrupt transitions from flat to radius. Brembo site says some GT series calipers are cast and some machined from billet. I'm betting these are cast, but again, not really an impact on performance here.

Again, having to have a bracket is a DISadvantage vs. not having one. Honestly though not a *huge* deal, but I'd rather not have the additional bolted joint interfaces.

Regarding pad thickness, yeah, if you wanna go endurance racing, that'd be an advantage. For my usage (track days, time trials, 15-25 minute stints, ~15-20 hours track time per year), not really. If having all that extra pad thickness is critical and "betteer", then once you're worn down a bit to PP pad thickness this advantage has totally gone away. In my experience you have to get the pad material pretty thin before there's any issue here. At least with decent pad compounds.

Regarding price, yeah, if I had a non-PP car and wanted to upgrade, I'd more likely go with the more cost-effective option. But more likely Id optimize the system I had and save my $$$$. Again, $1200 for the upgrade, already installed, totally worth it for me, and, yes, a BARGAIN!

[Irace86.2.0]

Originally Posted by Willpower

You boys have gotten to the place where you are talking waaaaay over my pay grade on brake systems for cars haha! Now if you want to discuss treatment for stubborn supraspinatus tendinitis, novel manual therapy techniques for the arthrofibrotic knee following total knee arthroplasty, or the effects of high amplitude therapeutic exercise on the functional mobility of folks with Parkinson’s disease, well then I can wade back in with some expertise anyway.

ZDan: Damn. You go boy!
Irace86: Smart and stubborn modifier of NICE cars, I have just one more message...
DEAL OF THE CENTURY BABY!!!

Wishing you both Happy and Safe Holidays!

We could talk about that I guess. BS in Exercise Physiology, NASM CPT/CES, some work on my masters, but currently 10+ year healthcare/ER Tech waiting to start nursing school this next fall. Shoot ahead. What do you got?

[ZDan]

Originally Posted by Willpower

DEAL OF THE CENTURY BABY!!!

Wishing you both Happy and Safe Holidays!

Happy Solstice and Happy Holidays!

I just seent the Jupiter/Saturn conjunction, dayum! Hoping it's a harbinger of good times for us all ahead

[HaXx]

Coincidence? I THINK NOT!

[HaXx]

Image taken from the official sti Instagram page. https://www.instagram.com/subaru.tecnica.international/

dont get too excited, the posts are tagged #vizivconcept
these are obviously just cool 1off concepts to promote the brand

[Willpower]

Originally Posted by Irace86.2.0

We could talk about that I guess. BS in Exercise Physiology, NASM CPT/CES, some work on my masters, but currently 10+ year healthcare/ER Tech waiting to start nursing school this next fall. Shoot ahead. What do you got?

Nice! You have my highest respect for going into nursing, and still keeping with that plan in the face of Covid 19. I have worked with some outstanding nurses in my time, and have the utmost respect for the profession. I enjoyed having their backs when I worked in the acute care setting, and was grateful that they always had mine. I’d like to think we had some damn good teams working in the service of our patients. And I’ve worked with some crackerjack CPTs as well. That background will make you a rather rare asset to the nursing profession, and if you work in acute care, the PTs will love working with you!
I’m a physical therapist, been practicing since the 90s. I have my doctorate but don’t wear it on my sleeve, as some of the best PTs I’ve worked with are folks that entered the profession back when a BS was all that was offered. Hard to beat experience! I believe all educational programs in the US have now converted to entry level doctoral programs.
I’ve worked in acute care, pediatrics, and outpatient orthopaedics, and just over 5 years ago went into business with my son (also a PT) and we opened our own clinic. We’re jacks of all trades to a degree, but we prefer working with folks with neuromuscular disorders, in particular Parkinson’s disease, though we have patients with other, less common pathologies, and enjoy working with those folks as well.
Again, I commend you for going into nursing. I worry that Covid 19 is going to make all health care professions less appealing to folks than they have been, and all healthcare professionals always are in short supply as it is. Hopefully we have some light at the end of the tunnel with the mRNA vaccines here now, but we still have a long and I’m afraid dark winter ahead.

[Willpower]

Originally Posted by ZDan

Happy Solstice and Happy Holidays!

I just seent the Jupiter/Saturn conjunction, dayum! Hoping it's a harbinger of good times for us all ahead

Me too brother!

[Irace86.2.0]

Originally Posted by ZDan

Um, nah...

Not that forged material offers any real advantage in this application, but the GT calipers for the BRZ for sure look to me to be *cast*, I see draft angles and more blended radii vs. typical machined calipers with no draft and visible abrupt transitions from flat to radius. Brembo site says some GT series calipers are cast and some machined from billet. I'm betting these are cast, but again, not really an impact on performance here.

Again, having to have a bracket is a DISadvantage vs. not having one. Honestly though not a *huge* deal, but I'd rather not have the additional bolted joint interfaces.

Regarding pad thickness, yeah, if you wanna go endurance racing, that'd be an advantage. For my usage (track days, time trials, 15-25 minute stints, ~15-20 hours track time per year), not really. If having all that extra pad thickness is critical and "betteer", then once you're worn down a bit to PP pad thickness this advantage has totally gone away. In my experience you have to get the pad material pretty thin before there's any issue here. At least with decent pad compounds.

Regarding price, yeah, if I had a non-PP car and wanted to upgrade, I'd more likely go with the more cost-effective option. But more likely Id optimize the system I had and save my $$$$. Again, $1200 for the upgrade, already installed, totally worth it for me, and, yes, a BARGAIN!

I initially was going for PT. It was a masters then, but I was told the field was saturated, as if there were 4 PTs for every one patient. I was talked out of being a sports medicine doc. Frankly, med school didn’t sound great at 22, nor did maximizing the performance of, or mending the injuries of, 0.01% of the population. I decided to work on a PHD because I liked teaching, science and theory, but not the practice, I discovered. I dropped out. Congrats for your academic achievements. I’ve been in healthcare so long, I feel like I am already a nurse. School should be a piece of cake. COVID doesn’t really deter me, but I agree that it might deter many. Stay safe