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Brake Caliper Insight Needed

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cholmes1

400lb Gorilla
350
216
Denver, CO
I am looking at a variety of options for my front brake upgrade and am curious if someone can provide me 'non-sales' information about why one caliper is superior to another. I have five calipers that I am looking at for the front of my '13 Boss running 305 square.

To my eye, the monoblock design looks to be primarily for strength to handle the added pistons (4 v. 6) but that cannot be the lone reason for the solid aluminum bridge across the top as the PP kits offer 6 pistons without. From a pad changing standpoint this appears to be a large negative for the XA5TO and GT350, but still learning, I am curious to know the performance advantages and disadvantages of each. The XA2E7 was the FRPP selection for the Boss 302S vehicles, but the XB105 appears to be identical short of the removable aluminum bridge. Again, was this for strength or were the pad c-clips not seating properly and this is extra security?

The performance kits are clearly hard anodized and likely have higher wearing internals that can better handle the heat generated in regular track use, but again, I am not certain. The OEM units are substantially cheaper than the motorsports versions, but is this due to the volume of production or significant technology improvements in the motorsports units?

EDIT based on JAJ feedback: These calipers all currently exist as kits for the S197 platform. The ease of the install and maintenance would vary widely for each

Thank you in advance for anyone able/willing to assist.

Brembo XA5T0 (6 Piston) Monoblock Caliper

Brembo XA5T0 6 Piston Monoblock Caliper.JPG

Brembo XB105 (4 Piston) Bolt-In Caliper

Brembo XB105 4 Piston Bolt-In Caliper.JPG

Brembo XA2E7 (4 Piston) Swing Caliper

Brembo XA2E7 4 Piston Swing Caliper.JPG

GT350 OEM Monoblock (6 Piston)

Brembo GT350 6 Piston Caliper.JPG

2015-2019 Brembo Performance Pack (6 Piston)

Brembo Mustang PP 6 Piston Caliper.JPG
 
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Mad Hatter

Gotta go Faster
5,237
4,227
Santiago, Chile
Only had the oem Boss brembos and then upgraded to the S550 6 pot Brembo setup. It was a great upgrade and with race pads like Gloc or Pagid pads, the results have been very good. Probably the best feature of the car, in my series, is the braking. Pads are widely availble and just using the stock discs as they are very cheap and you go through 2 o 3 sets a season.

Am sure that some of the more track oriented kits are better, but these OEM 15" Brembos are a good budget choice. Was delighted to pass a GT3 because my brakes lasted longer then his!
 
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1,246
1,243
In the V6L
This is more complex than it looks. First, there are two different families of calipers - OEM and racing catalog. The OEM calipers have dust boots, aluminum pistons and are designed to be installed and run for a decade with the odd pad change. The bigger ones can handle more heat, with the GT350 caliper being the biggest and most capable. They don't all have the same piston sizes, so there might be some challenges with master cylinder and ABS.

The racing calipers are built differently. They don't have dust boots and they do (mostly) have stainless steel inserts on the pistons to reduce heat transfer. They need to be rebuilt regularly. They don't have anti-rattle springs, so the pads rattle around in the pockets - a lot - so they're noisy. They all take 25mm thick pads, so you get great pad life - OEM calipers have 16mm thick pads, which are a lot thinner. Also race pads for these calipers are pretty widely available, but street pads are not. I had the Brembo Racing track day kit on my 2014 GT500 and those brakes - 350x34 rotors with 4 piston XB1E7's - and they were flat out awesome with ST42 pads. Carbotech made me a custom set of street pads for them. @Fabman has them now, if you're curious how they work. He did a thread on this forum about them after he installed them. By the way, the three different calipers you list all have different mounting centers, and they're designed for different uses. The challenge will be finding brackets and rotor sets that work with them - they're far from interchangeable with each other or with anything else.

So, you're choosing between OEM and racing, take a look at the Brembo Racing kit I mentioned. Easy to install, easy to swap pads and works well under heavy use.

Update: It looks like you're trying to choose from the current range of Brembo Racing kits, so the good news is there won't be any issues with brackets or rotors. If I was looking at this, I'd go for the easy pad changes and choose between the two versions of the 4 piston calipers - XA2 or XB1 - and it really comes down to getting them to fit under your wheels. Thermal capacity of the 380's is higher, so it's a good option (I'd go for Type 3 rotors) but be very careful about making sure your wheels will fit - the bigger rotor means the top of the caliper might hit the inside of the wheel barrel and the thicker pads mean that the caliper body is wider and might hit the inside of the spokes.
 
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cholmes1

400lb Gorilla
350
216
Denver, CO
...By the way, the three different calipers you list all have different mounting centers, and they're designed for different uses. The challenge will be finding brackets and rotor sets that work with them - they're far from interchangeable with each other or with anything else.

So, you're choosing between OEM and racing, take a look at the Brembo Racing kit I mentioned. Easy to install, easy to swap pads and works well under heavy use.

Thank you for the response and personal experience/reaction. For reference, since it was not originally listed in the OP, all of these are available in kits for the S197 platform so while they are not immediately interchangeable they are all possible on the Boss platform.
 
1,246
1,243
In the V6L
Thank you for the response and personal experience/reaction. For reference, since it was not originally listed in the OP, all of these are available in kits for the S197 platform so while they are not immediately interchangeable they are all possible on the Boss platform.
Yes, I figured that out - see the update on my first post. Also, from experience, I'd bypass all the "upgrade with OEM parts" options. If you need robust braking and the car's basically for track use, then get the Brembo Racing kit. When I had them on my GT500, I had them connected with Staubli's and I could swap calipers, brackets and rotors in about 20 minutes a side because I didn't have to bleed them. I ran factory parts for day-to-day and real race parts for track days.
 

cholmes1

400lb Gorilla
350
216
Denver, CO
@JAJ Thank you for the update. I had not heard of Staubli and it appears to be a great option for those that serve time on the street and track. You did mention that you Carbotech made you street pads for your race setup, how complicated was that process and how well did they work? I assume based on your notes of "...they need to be rebuilt regularly. They don't have anti-rattle springs, so the pads rattle around in the pockets - a lot - so they're noisy." it was not an ideal situation which is why you chose the Staubli option. Is this correct?
 
1,246
1,243
In the V6L
@JAJ Thank you for the update. I had not heard of Staubli and it appears to be a great option for those that serve time on the street and track. You did mention that you Carbotech made you street pads for your race setup, how complicated was that process and how well did they work? I assume based on your notes of "...they need to be rebuilt regularly. They don't have anti-rattle springs, so the pads rattle around in the pockets - a lot - so they're noisy." it was not an ideal situation which is why you chose the Staubli option. Is this correct?
Pretty much. At the time, the car was my daily and the racket (the supplied ST42 pads were school-bus noisy) just wasn't going to work when I had to ferry around passengers from work. Getting the street pads was easy - contact a Carbotech dealer and say "I need this compound on this backing plate". No magic required. The backing plates are standard Brembo B18 or B19 (don't remember which) and there's nothing exotic about it. They worked fine but they still rattled around like crazy, but at least they didn't squeal.

The Staubli thing actually started with a different brand of connector - TorquesUK - and they worked great and were relatively affordable. I designed a set of modified OEM front brake hoses (still have them) with a special bracket that isolated the connectors from the motion of the front suspension, so there was no twisting or stress on the 3AN fittings or connectors while driving. Thing with them was that I used Castrol SRF at the time, and Castrol reformulated it to SRF React, and the new formula ate all the rubber components in the Torques connectors causing them to leak. So, I checked with Staubli, and they confirmed their connectors would work with the new Castrol fluid, so I ordered a set from Pegasus and all was well again. One of the fun things was the kit I set up on my pressure bleeder - I had a hose with a connector and a vertical bracket so I could flush and bleed the calipers when they were off the car. Pretty handy, that.
 
Well I searched Brembo's website and I only saw 6-piston calipers listed specifically for the BOSS302. I saw 3 options, 2 of which are cast aluminum which are the GT line. These are like the OEM calipers so there aren't any upgrades there. The third option is the billet monoblock (GT-R line), which I believe is the XB105 you've listed.

When talking calipers only, you want them to be as stiff as possible and as light as possible. The bridge is to add stiffness and the design varies widely. They come in as bolts like in the 13 GT500 or part of the casting like the GT350. The more advanced designs are more complicated (look at stoptech or AP). The cast Aluminum suffers from being heavy, and it loses stiffness as it heats up. Thats why the racing calipers are either forged or machined from billet.
As for internals, AP claims that you don't need dust boots and it won't effect the longevity of the caliper. "If you have a product that is specifically designed to handle the extraordinary high-heat conditions of track use, why would it require more maintenance when used under those conditions vs. brake components that were designed to cruise around on the streets at low speed and temperature?:

Why are looking at upgrading you're brakes? Have you had issues with you're current setup?
 
1,246
1,243
In the V6L
Well I searched Brembo's website and I only saw 6-piston calipers listed specifically for the BOSS302. I saw 3 options, 2 of which are cast aluminum which are the GT line. These are like the OEM calipers so there aren't any upgrades there. The third option is the billet monoblock (GT-R line), which I believe is the XB105 you've listed.

When talking calipers only, you want them to be as stiff as possible and as light as possible. The bridge is to add stiffness and the design varies widely. They come in as bolts like in the 13 GT500 or part of the casting like the GT350. The more advanced designs are more complicated (look at stoptech or AP). The cast Aluminum suffers from being heavy, and it loses stiffness as it heats up. Thats why the racing calipers are either forged or machined from billet.
As for internals, AP claims that you don't need dust boots and it won't effect the longevity of the caliper. "If you have a product that is specifically designed to handle the extraordinary high-heat conditions of track use, why would it require more maintenance when used under those conditions vs. brake components that were designed to cruise around on the streets at low speed and temperature?:

Why are looking at upgrading you're brakes? Have you had issues with you're current setup?
You were on the Brembo consumer website. Brembo Racing parts are on https://www.racetechnologies.com - Race Technologies is essentially Brembo's North American racing support and distribution arm. As for AP Racing, they have great stuff too, but don't be misled by reseller hype. Here's what the actual APRacing.com website says about rebuilds: https://apracing.com/race-car/brake-calipers/brake-caliper-seals-temperature

"Because race brake calipers are sometimes subjected to very high and unpredictable operating temperatures, they must be examined and seals must be replaced on a regular basis to maintain efficiency and safety. Seal life is governed by time at temperature which should therefore be kept as low as possible by provision of cooling airflow. For guidance only AP Racing offer the following recommendations (temperatures measured on outside of caliper adjacent to logo): - Calipers that regularly run at up to 200°C - Re-seal every other event. - Calipers that run intermittently from 200°C to 220°C abd above - Re-seal as soon as possible. - Reduce "soak" temperatures after the car has come to rest where possible (e.g. do not leave foot on brake pedal when stationary with hot brakes) as this can cause excessive caliper temperatures."
 

cholmes1

400lb Gorilla
350
216
Denver, CO
Why are looking at upgrading you're brakes? Have you had issues with you're current setup?

Thank you for your insights. No issues with my current brakes, but I have always been a fan of future-proofing. The car is already well beyond my abilities, but like my father and his golf clubs, if I buy the 'best' then I cannot blame the equipment
 
Thank you for your insights. No issues with my current brakes, but I have always been a fan of future-proofing. The car is already well beyond my abilities, but like my father and his golf clubs, if I buy the 'best' then I cannot blame the equipment

I see, well the stock brake setup is more than capable and can go beyond that with upgrades. Given that you have the basics, brake ducts and a good pad, you can buy stainless steel pistons, SS lines and upgrade to two piece rotors and that would be more than enough without breaking the bank on a BBK.

Also, I personally don't like the brembo kits because of their price, they are way too expensive for even their entry level and you only get the benefits of a two piece rotor on their GT line. You are looking at $6800 or more for the better calipers.
 

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