[M3SQRD]

Originally Posted by TopJimmy

M3SQRD I know I can’t speak to the bolts and stuff, but you had asked about pad centering. Today while swapping wheels I measured both inside and outside edge ridges, which were 2.0 and 1.6mm, so the pads are centered well. My pix are completely parallel and show how the pads do sit straight, not crooked.

Hum…I would have preferred to have a wider unswept area at the rotor IR (3.6 mm) than a 1.6 mm unswept area at the rotor OR. Once the rotor starts to wear, you won’t be able to install a new set of pads. You’re now stuck having to change rear rotors every time you have to swap rear pads.

[ginohhh]

For those asking about the rotors, they were rockauto rotors. I have since swapped them to the oem rotors.

And there are no shavings on the caliper? It’s a crappy pic. I will post an updated pic of what they look like up close.

I have no complaints thus far and love the kit.

[nbennettksu]

Originally Posted by ginohhh

For those asking about the rotors, they were rockauto rotors. I have since swapped them to the oem rotors.

And there are no shavings on the caliper? It’s a crappy pic. I will post an updated pic of what they look like up close.

I have no complaints thus far and love the kit.

He’s making mine now 😍

[dentprotony@gmail.com]

Originally Posted by M3SQRD

I think it’s a mistake but the oem rotors don’t have a hat connected to the rotor so it might be harder to see it. The real question is whether there’s full coverage at the rotor OD without any pad overhang. The second picture makes it look like there’s a lot of pad overhang but I hope that’s due to the caliper black mounting SHCS not being completely installed.

M3sqrd pads are separated in the picture, owner just installed the caliper and pistons arent compressed yet but visually look like pads overhang. Somehow most on here (not in any other group like m5, x5m/x5, x3m) think somehow my kits are raggedy with pads hanging over the rotor edge, grounded down parts etc etc etc. we also had a discussion on total piston area a couple months prior.
Each kit that i provide undergoes rigorous testing, thats severe braking /overheating attempt, fit and finish qc, material that we use are also picked very carefully. It takes me months to release a kit, thats why ccb crowd was crying for a month or so now because it takes me 1.5-2.5 months to release a new kit. From scan to study to cnc to however many revisions it takes to build the 🔥🔥🔥🔥🔥 set up that is both looking top notch and delivers at least comparable to stock but usually substantially better and more consistent braking performance.
I have multiple nice vehicles incl m5, x5m, not slow duramax, and an m40i.each kit goes through my hands from beginning to the post office hence it takes me a good bit to build/assemble/wrap and ship out. I am VERY picky about my cars and i would not want junky trashy half ass parts on any of my vehicles. I wont want this for my customers for sure.
I definitely would not be one of the very well known people in the bmw community over past 8-9 years by providing half ass work or crappy fitting kits/parts. My name comes up 5-6 times a day on fb, i am not as active here because i am overwhelmed with work as is already.
I am the one who cane up with the driveline solution for thousands of x5 vehicles and these driveshafts sell out weekly before they even built.

As far as the pictures go, op and i had a deal that in exchange for a lower price he will post a ton of pictures and an install video. 2-3 months later this was all i got with aftermarket rockauto rotors which are meh in my book. I am working on getting a video done by another member as well as perhaps finding a local m3/4/2 owner and making a YouTube install like i usually do.

PS picture of the pad is angled, you see pad backing plate but actual pad material is not visible/hazy (shitty picture), pad is about 1mm shorter on the disc vs stock, it is negligible imo and it is also 1.5mm inside the rotor edge. Overall kit fit and performance is superb. Just shitty pictures but ill address this soon just crazy busy

PPS anyone can text me 6016181023 if yall have any questions, concerns, so far i have about 8-9 kits out and everyone was beyond happy with these

[M3SQRD]

dentprotony@gmail.com

First, I wasn’t suggesting your kit’s inferior or junky. I’m just trying to understand a few critical details.

TopJimmy’s rear pad has an unworn/unswept area at the rotor OD. Is this not correct? Are there new pictures of your other kit (OP) with the blue caliper kit?

I’m not clear on how your large adapter is secured to the rear hub? Load path and magnitudes are very different from stock. Any structural hand and/or FE analyses performed to ensure the design satisfies loading requirements and fracture mechanics life? This is one of the major critical safety systems on a car. If I’m interpreting the mounting locations correctly, the magnitude of the braking/caliper loads are higher and the load path is more complex. Are straight tapped aluminum holes being used? This will eventually, possibly even during its initial installation, result in a galling issue(s) between tapped aluminum holes with steel fasteners.

[dentprotony@gmail.com]

Originally Posted by M3SQRD

dentprotony@gmail.com

First, I wasn’t suggesting your kit’s inferior or junky. I’m just trying to understand a few critical details.

TopJimmy’s rear pad has an unworn/unswept area at the rotor OD. Is this not correct? Are there new pictures of your other kit (OP) with the blue caliper kit?

I’m not clear on how your large adapter is secured to the rear hub? Load path and magnitudes are very different from stock. Any structural hand and/or FE analyses performed to ensure the design satisfies loading requirements and fracture mechanics life? This is one of the major critical safety systems on a car. If I’m interpreting the mounting locations correctly, the magnitude of the braking/caliper loads are higher and the load path is more complex. Are straight tapped aluminum holes being used? This will eventually, possibly even during its initial installation, result in a galling issue(s) between tapped aluminum holes with steel fasteners.

Heres a couple pictures from one of the g80 threads on fb for fitment reference.there is mo FE analysis made for load dissipation/reaction , t7075 plate is secured by 5 fasteners (2xM12 and 3xM8), plate and spindle are both aluminum, i also do not see galling to take place given this particular set up and considering rear brakes aredoing 30% of the job. I would go on a limb and state that aftermarket brake companies (wilwood etc) do not perform this particular analysis either. I have wilwood 16” kit on my duramax and brackets appear to be weaker than what my x5m kits come with. Thats 9100lb truck with 35” tires that pulls. But again im being more emotional than scientific, i have no proof to the last claim i admit.

[clutchdj]

Originally Posted by dentprotony@gmail.com

M3sqrd pads are separated in the picture, owner just installed the caliper and pistons arent compressed yet but visually look like pads overhang. Somehow most on here (not in any other group like m5, x5m/x5, x3m) think somehow my kits are raggedy with pads hanging over the rotor edge, grounded down parts etc etc etc. we also had a discussion on total piston area a couple months prior.
Each kit that i provide undergoes rigorous testing, thats severe braking /overheating attempt, fit and finish qc, material that we use are also picked very carefully. It takes me months to release a kit, thats why ccb crowd was crying for a month or so now because it takes me 1.5-2.5 months to release a new kit. From scan to study to cnc to however many revisions it takes to build the 🔥🔥🔥🔥🔥 set up that is both looking top notch and delivers at least comparable to stock but usually substantially better and more consistent braking performance.
I have multiple nice vehicles incl m5, x5m, not slow duramax, and an m40i.each kit goes through my hands from beginning to the post office hence it takes me a good bit to build/assemble/wrap and ship out. I am VERY picky about my cars and i would not want junky trashy half ass parts on any of my vehicles. I wont want this for my customers for sure.
I definitely would not be one of the very well known people in the bmw community over past 8-9 years by providing half ass work or crappy fitting kits/parts. My name comes up 5-6 times a day on fb, i am not as active here because i am overwhelmed with work as is already.
I am the one who cane up with the driveline solution for thousands of x5 vehicles and these driveshafts sell out weekly before they even built.

As far as the pictures go, op and i had a deal that in exchange for a lower price he will post a ton of pictures and an install video. 2-3 months later this was all i got with aftermarket rockauto rotors which are meh in my book. I am working on getting a video done by another member as well as perhaps finding a local m3/4/2 owner and making a YouTube install like i usually do.

PS picture of the pad is angled, you see pad backing plate but actual pad material is not visible/hazy (shitty picture), pad is about 1mm shorter on the disc vs stock, it is negligible imo and it is also 1.5mm inside the rotor edge. Overall kit fit and performance is superb. Just shitty pictures but ill address this soon just crazy busy

PPS anyone can text me 6016181023 if yall have any questions, concerns, so far i have about 8-9 kits out and everyone was beyond happy with these

hi has this kit been tested on any tracks with constant (sessions) heat on it. I'm thinking about the constant brake torque on these, ie; say I want to bias my braking to the rear via different pad coefficients on the f&r axles. tia

[SwankPeRFection]

So two things that maybe you knew or didn’t know… 1) The bleed screw isn’t in the perfect 12 o’clock position as it should be, but it’s somewhat close enough in orientation to where it might not matter much.
2) You changed the brake force design from a compression generating force to a lift generating force with putting that caliper on the back side of the rotor.

[M3SQRD]

Originally Posted by dentprotony@gmail.com

Heres a couple pictures from one of the g80 threads on fb for fitment reference.there is mo FE analysis made for load dissipation/reaction , t7075 plate is secured by 5 fasteners (2xM12 and 3xM8), plate and spindle are both aluminum, i also do not see galling to take place given this particular set up and considering rear brakes aredoing 30% of the job. I would go on a limb and state that aftermarket brake companies (wilwood etc) do not perform this particular analysis either. I have wilwood 16” kit on my duramax and brackets appear to be weaker than what my x5m kits come with. Thats 9100lb truck with 35” tires that pulls. But again im being more emotional than scientific, i have no proof to the last claim i admit.

Galling is due to dissimilar material running against each other. When you screw a steel/SS fastener into a straight tapped aluminum hole. Also the pullout strength of tapped aluminum hole is extremely low and that’s why SS or phosphorus bronze helicoils are used in aluminum areas that require threading.

What temper/heat treatment of 7075 is used; e.g., 7075-T351, 7075-T73, 7075-T6, etc? 7075 strength drops off by 30-40% at temps between 200-300 F. Fatigue life with a SCF = 4.0 and a R ratio of 0 has a stress runout limit (infinite cycles) of ~6 ksi so any stress >= 6 ksi eats into the fatigue life of 7075 parts. Post-machined parts re-heat treated?

Your method of mounting your large adapter brake is very different from making a caliper adapter bracket that bolts to the same threaded holes as the stock caliper. Top brake manufacturers will at least perform structural hand analyses of their braking kits which would take < 10 min to complete. Brakes are a critical human safety system that comes with liability. Your method used to secure the caliper adapter bracket is still not clear to me. No FB account. Is it the two holes outboard of where the caliper mounts and the three raised threaded bosses? What’s the cross-sectional area width and height? This large adapter bracket adds a lot of compliance compared to simple adapter brackets. What’s the purpose of the vertical wall at the top of the adapter bracket in your pics above? Your mounting scheme subjects the caliper bracket to tension, shear and bending which is far worse than the loads a typical caliper adapter bracket is subjected to. The three raised bosses also introduce local bending to the 3x M8 fasteners going into tapped aluminum holes. Mixing fastener sizes is poor design practice and affects the load distribution.

I’m still not saying your four-piston caliper kit doesn’t function properly.

[dentprotony@gmail.com]

Originally Posted by M3SQRD

Galling is due to dissimilar material running against each other. When you screw a steel/SS fastener into a straight tapped aluminum hole. Also the pullout strength of tapped aluminum hole is extremely low and that’s why SS or phosphorus bronze helicoils are used in aluminum areas that require threading.

What temper/heat treatment of 7075 is used; e.g., 7075-T351, 7075-T73, 7075-T6, etc? 7075 strength drops off by 30-40% at temps between 200-300 F. Fatigue life with a SCF = 4.0 and a R ratio of 0 has a stress runout limit (infinite cycles) of ~6 ksi so any stress >= 6 ksi eats into the fatigue life of 7075 parts. Post-machined parts re-heat treated?

Your method of mounting your large adapter brake is very different from making a caliper adapter bracket that bolts to the same threaded holes as the stock caliper. Top brake manufacturers will at least perform structural hand analyses of their braking kits which would take < 10 min to complete. Brakes are a critical human safety system that comes with liability. Your method used to secure the caliper adapter bracket is still not clear to me. No FB account. Is it the two holes outboard of where the caliper mounts and the three raised threaded bosses? What’s the cross-sectional area width and height? This large adapter bracket adds a lot of compliance compared to simple adapter brackets. What’s the purpose of the vertical wall at the top of the adapter bracket in your pics above? Your mounting scheme subjects the caliper bracket to tension, shear and bending which is far worse than the loads a typical caliper adapter bracket is subjected to. The three raised bosses also introduce local bending to the 3x M8 fasteners going into tapped aluminum holes. Mixing fastener sizes is poor design practice and affects the load distribution.

I’m still not saying your four-piston caliper kit doesn’t function properly.

Bracket is made out of t7075-t651 that meets AMS QQA 250/12, ASTM-B209, AND AMS 4045 (my cnc shop response). Brackets are not exposed to heat (barely any) , if anything caliper is exposed to much more and harder heat cycles, even on consecutive harsh stops from 100+ to near complete stop calipers get warm to the touch but not hot. Also when parts are cut they are flooded with coolant to keep the temps low close to ambient
Bracket is secured to spindle by 2 m12 bolts and 3 fasteners that bolt into the heat shield bolt locations. Pictured is the back of the plate, the other side is flat that actually faces the rotor.
My fb name is Tony Chumakov, reason caliper is on the opposite side is because stock epb plug will not reach to the opposite side of the wheel, but brake hose can be built to any length necessary. Vertical wall is where 4 piston caliper is mounted to.

[dentprotony@gmail.com]

Originally Posted by clutchdj

hi has this kit been tested on any tracks with constant (sessions) heat on it. I'm thinking about the constant brake torque on these, ie; say I want to bias my braking to the rear via different pad coefficients on the f&r axles. tia

Two of my customers frequently take their g80 to the track (op actually does), bracket is not exposed to any abnormal heat cycles because it is away from disc , caliper does undergo some stress but again it is a panamera caliper that is not a stranger to severe braking, thats the caliper i use on most of my builds and many of my customers are extremely harsh on their brakes/vehicles, so far it stood to whatever was thrown at it

[clutchdj]

Ok. PM sent

[nbennettksu]

I can't wait for mine to come

[M3SQRD]

Originally Posted by SwankPeRFection

So two things that maybe you knew or didn’t know… 1) The bleed screw isn’t in the perfect 12 o’clock position as it should be, but it’s somewhat close enough in orientation to where it might not matter much.
2) You changed the brake force design from a compression generating force to a lift generating force with putting that caliper on the back side of the rotor.

I pointed this out in a previous post.

Don’t you mean the caliper should be located roughly at the 3 or 9 o’clock position so the bleed valve is close to being vertical at the top of the caliper (valve always pointing roughly vertically upward at the top of the caliper)?

Caliper torque reaction is different and the large mounting bracket adds compliance and a more complex load path.

[M3SQRD]

Originally Posted by dentprotony@gmail.com

Bracket is made out of t7075-t651 that meets AMS QQA 250/12, ASTM-B209, AND AMS 4045 (my cnc shop response). Brackets are not exposed to heat (barely any) , if anything caliper is exposed to much more and harder heat cycles, even on consecutive harsh stops from 100+ to near complete stop calipers get warm to the touch but not hot. Also when parts are cut they are flooded with coolant to keep the temps low close to ambient
Bracket is secured to spindle by 2 m12 bolts and 3 fasteners that bolt into the heat shield bolt locations. Pictured is the back of the plate, the other side is flat that actually faces the rotor.
My fb name is Tony Chumakov, reason caliper is on the opposite side is because stock epb plug will not reach to the opposite side of the wheel, but brake hose can be built to any length necessary. Vertical wall is where 4 piston caliper is mounted to.

7075-T651 is a table III stress corrosion cracking material. Table III materials have a very low resistance to SCC and requires detailed analysis to show there’s no stress > 30% of yield strength. 7075-T7351 is the appropriate heat treated version of 7075 to be used.

Bracket is directly connected to the heat source - the caliper which is not ideally mounted. Aluminum has a high coefficient of thermal conductivity so the heat will be transferred around the continuous mounting bracket. So the calipers are only warm to the touch after a 20-30 min track session? If that’s the case then you’re saying the rear brakes are not contributing any braking torque to the overall total braking torque? What are caliper temps when someone is using MDM on track?

The heat shield mounting points are designed to react the weight of the heat shield, not primary braking tension, shear and moments. The circular standoffs on the adapter at the head shield mounting locations results in secondary moments (shear reaction is vertically offset so M = V*d) being reacted by heat shield mounting points in addition to the primary caliper-induced loads.

Caliper mounts to the vertical wall, not where there’s a caliper footprint machined into the horizontal plane on the lower edge? Or you talking about the raised boss where the caliper mounting footprint is machined? Which set of arrows in the first pic point to the caliper mounting locations? If the lower mounting bods is correct, what’s the purpose of the upper vertical wall/edge? Pad knockback is likely a concern due to the large footprint adapter with in-plane and out-of-plane compliance due to three primary support points being heat shield mounting locations with tall integrally machined cylindrical bosses. In pic 2, are the five mounting locations correctly identified?

[Tall Tom Cruise]

Originally Posted by M3SQRD

7075-T651 is a table III stress corrosion cracking material. Table III materials have a very low resistance to SCC and requires detailed analysis to show there’s no stress > 30% of yield strength. 7075-T7351 is the appropriate heat treated version of 7075 to be used.

Bracket is directly connected to the heat source - the caliper which is not ideally mounted. Aluminum has a high coefficient of thermal conductivity so the heat will be transferred around the continuous mounting bracket. So the calipers are only warm to the touch after a 20-30 min track session? If that’s the case then you’re saying the rear brakes are not contributing any braking torque to the overall total braking torque? What are caliper temps when someone is using MDM on track?

The heat shield mounting points are designed to react the weight of the heat shield, not primary braking tension, shear and moments. The circular standoffs on the adapter at the head shield mounting locations results in secondary moments (shear reaction is vertically offset so M = V*d) being reacted by heat shield mounting points in addition to the primary caliper-induced loads.

Caliper mounts to the vertical wall, not where there’s a caliper footprint machined into the horizontal plane on the lower edge? Or you talking about the raised boss where the caliper mounting footprint is machined? Which set of arrows in the first pic point to the caliper mounting locations? If the lower mounting bods is correct, what’s the purpose of the upper vertical wall/edge? Pad knockback is likely a concern due to the large footprint adapter with in-plane and out-of-plane compliance due to three primary support points being heat shield mounting locations with tall integrally machined cylindrical bosses. In pic 2, are the five mounting locations correctly identified?

Bumping for a response to these questions/concerns.

[SE7EN335]

Originally Posted by M3SQRD

7075-T651 is a table III stress corrosion cracking material. Table III materials have a very low resistance to SCC and requires detailed analysis to show there’s no stress > 30% of yield strength. 7075-T7351 is the appropriate heat treated version of 7075 to be used.

Bracket is directly connected to the heat source - the caliper which is not ideally mounted. Aluminum has a high coefficient of thermal conductivity so the heat will be transferred around the continuous mounting bracket. So the calipers are only warm to the touch after a 20-30 min track session? If that’s the case then you’re saying the rear brakes are not contributing any braking torque to the overall total braking torque? What are caliper temps when someone is using MDM on track?

The heat shield mounting points are designed to react the weight of the heat shield, not primary braking tension, shear and moments. The circular standoffs on the adapter at the head shield mounting locations results in secondary moments (shear reaction is vertically offset so M = V*d) being reacted by heat shield mounting points in addition to the primary caliper-induced loads.

Caliper mounts to the vertical wall, not where there’s a caliper footprint machined into the horizontal plane on the lower edge? Or you talking about the raised boss where the caliper mounting footprint is machined? Which set of arrows in the first pic point to the caliper mounting locations? If the lower mounting bods is correct, what’s the purpose of the upper vertical wall/edge? Pad knockback is likely a concern due to the large footprint adapter with in-plane and out-of-plane compliance due to three primary support points being heat shield mounting locations with tall integrally machined cylindrical bosses. In pic 2, are the five mounting locations correctly identified?

Bumping this up too

[nbennettksu]

Finished mine one Friday 🙏

[dentprotony@gmail.com]

Originally Posted by M3SQRD

7075-T651 is a table III stress corrosion cracking material. Table III materials have a very low resistance to SCC and requires detailed analysis to show there’s no stress > 30% of yield strength. 7075-T7351 is the appropriate heat treated version of 7075 to be used.

Bracket is directly connected to the heat source - the caliper which is not ideally mounted. Aluminum has a high coefficient of thermal conductivity so the heat will be transferred around the continuous mounting bracket. So the calipers are only warm to the touch after a 20-30 min track session? If that’s the case then you’re saying the rear brakes are not contributing any braking torque to the overall total braking torque? What are caliper temps when someone is using MDM on track?

The heat shield mounting points are designed to react the weight of the heat shield, not primary braking tension, shear and moments. The circular standoffs on the adapter at the head shield mounting locations results in secondary moments (shear reaction is vertically offset so M = V*d) being reacted by heat shield mounting points in addition to the primary caliper-induced loads.

Caliper mounts to the vertical wall, not where there’s a caliper footprint machined into the horizontal plane on the lower edge? Or you talking about the raised boss where the caliper mounting footprint is machined? Which set of arrows in the first pic point to the caliper mounting locations? If the lower mounting bods is correct, what’s the purpose of the upper vertical wall/edge? Pad knockback is likely a concern due to the large footprint adapter with in-plane and out-of-plane compliance due to three primary support points being heat shield mounting locations with tall integrally machined cylindrical bosses. In pic 2, are the five mounting locations correctly identified?

Sorry for the late response, crazy busy with work and family, as far as corrosion properties of the aluminum that is used, yes it is not the best out of 3 available, but additional steps are taken to help prevent corrosion and brackets are also anodized after they are cut to spec. I will consider using other alloys but from the last 4 years i been building brackets out of 7075 aluminum i only had issue once , it was a canada customer and i believe the shop that installed his kit (now consider the fact that my x5 brackets are smaller and skinnier than g80 brackets), shop used an impact vs using torque wrench and essentially cracked the bracket and over time , element exposure, and daily use brackets developed stress cracks. I will definitely talk to the shop but again im pretty confident corrosion will not be an issue given anodization as an additional protective step

Temps come from personal experience with my x5m, it is a heavier vehicle vs g80 , i dont track it but i do spiritually drive it every now and then , and with consecutive 100+ to 0 braking sessions front brake calipers get very warm to the touch (warm as in 100f or so) which will not distort the aluminum strength. I do not have experience in temps that rear g80 calipers would be exposed to, but considering that rear brakes are not as involved as the fronts i would ASSUME bracket structure will not be weakened because pad/caliper got hot. I went through some mixed info available and it seems that 7075t6 will start weakening at consistent exposure to 300F. From cosmetic standpoint i can tell you that caliper paint will wrinkle and ///M decal will be damaged at temps far below that. Again this is just a rule of thumb but *front* calipers (most braking) on my x5m get very warm to the touch (you still can touch them and hold your hand against them ) after 3-4 120-130 to a very low speed stops, and f85 is a very heavy vehicle.
Something very important to remember is that caliper is also made out of aluminum, heat exposure would affect the caliper and caliper seals/paint before anything else like a bracket etc. caliper doesn’t get hot hot, now Pads and pistons do see extreme temps.

I also attached a couple pictures to give an idea on the bracket mounting to the spindle. Dust shield bolts are used to assist any flex or vibration prevention, they do not carry any actual mounting or shear mission.

I definitely want to remind everyone that brake system is a crucial safety component, if anything looks sketchy about this set up , if any of the forum members dont feel comfortable or believe that any of this is unsafe or can lead to any brake system or safety issues in the future , id advise against using my set up and either stick with factory or go with many other true and well tested kits that are available on the market.

PS pictured is a bracket that will be tested for x3M f97 crew, g80 part looks a little different but i currently dont have any in stock, shop is cutting more just takes time to restock especially around Christmas time. This bracket is used to give an idea how everything is put together and secured to the factory spindle

PPS apologies for not responding fast enough, i been overwhelmed with work and trying to spend time with the family as much as i can

[M3SQRD]

dentprotony@gmail.com

7075-T7351 is a much better option than any 7075-T6xxx. Although it is quite expensive, 7050-T7452 is the best choice if parts are machined from plates > 3” thick. 7075-T7451 has very high residual temperatures. It’s common to rough machine a 7075-Txxxx part, reheat treat to minimize residual stress and then final machining of the part. SCC is not the same as common corrosion. SCC is due to salty air from being around oceans, etc. (east coast and west coast environments).

Calipers can reach 500-700 F on track and this temperature will spread throughout the bracket. A 20-25 min, especially a 45 min, session is a sufficient amount of time for the caliper heat to reach a steady-state temperature in the bracket due to the high thermal conductivity of aluminum. I’d ask someone who’s tracking your kit to place caliper temperature stickers and/or caliper temperature sensitive paint to understand the temperature distribution on the caliper adapter bracket. Yes, calipers are made from aluminum but the melting temperature of aluminum is around 1220 F. High-end race pads can reach temperatures above 1220 F but all of the pad temperatures are not transferred to the caliper/adapter bracket. Your large spaced out mounting points may have thermally-induced loads and strains epsilon_temp = alpha x DeltaT and the mechanical loads are F =
A x E x (epsilon_mech - epsilon_temp). My guess is it’ll be a secondary effect on mounting points.

How can the heat shield mounting fasteners not react any load? The stock calipers use M12 bolts whereas the heat shield uses M6 bolts. Very difficult strength and preloads. No supporting analysis showing the shear load distribution on the M6 fasteners (not uniform due to different stiffness at each caliper bracket mounting location) and their margins makes this kit unsafe, IMO. The EPB caliper uses the original main one-piston sliding caliper, correct? I haven’t seen the backside of the g8x rear brake hub so I’m not sure what the structure looks like that’s reacting the load.

Your mounting scheme is what results in an indeterminate load distribution; e.g., there are too many mounting points and too few equilibrium equations. The two fasteners closest to the two caliper attachment locations will react in more load than the rest of the adapter mounting points. Conservatively, I’d react all of the caliper lateral shear load (fastener shear loads in the two lateral directions) and differential axial fastener loads due to the bending moment from generated from the lateral shear offset of the caliper midplane to the adapter bracket (two fasteners react the moment as differential axial forces). If you can show positive margin with factors of safety of 3 (yield) and 5 (ultimate) with all loads, including thermally-induced loads, reacted by just the two fasteners then you should be fine. You could use a classical bolt group analysis to calculate the loads on all bracket mounting points but you’ll have to increase the different fastener tensile area and then assume a peaking factor to account for the statically indeterminate fastener layout.

[km111222]

Does anyone have any track pad recommendations that will fit these rear calipers AND are available for stock front calipers. Would appreciate any advice. Are RSL29s available? We've got this kit on the car with giro discs and DS2500 right now but would like a more dedicated track pad. Thanks.

[SneakyHobbitses]

Originally Posted by M3SQRD

dentprotony@gmail.com

7075-T7351 is a much better option than any 7075-T6xxx. Although it is quite expensive, 7050-T7452 is the best choice if parts are machined from plates > 3” thick. 7075-T7451 has very high residual temperatures. It’s common to rough machine a 7075-Txxxx part, reheat treat to minimize residual stress and then final machining of the part. SCC is not the same as common corrosion. SCC is due to salty air from being around oceans, etc. (east coast and west coast environments).

Calipers can reach 500-700 F on track and this temperature will spread throughout the bracket. A 20-25 min, especially a 45 min, session is a sufficient amount of time for the caliper heat to reach a steady-state temperature in the bracket due to the high thermal conductivity of aluminum. I’d ask someone who’s tracking your kit to place caliper temperature stickers and/or caliper temperature sensitive paint to understand the temperature distribution on the caliper adapter bracket. Yes, calipers are made from aluminum but the melting temperature of aluminum is around 1220 F. High-end race pads can reach temperatures above 1220 F but all of the pad temperatures are not transferred to the caliper/adapter bracket. Your large spaced out mounting points may have thermally-induced loads and strains epsilon_temp = alpha x DeltaT and the mechanical loads are F =
A x E x (epsilon_mech - epsilon_temp). My guess is it’ll be a secondary effect on mounting points.

How can the heat shield mounting fasteners not react any load? The stock calipers use M12 [...]

I think it’s pretty clear that you are an ME, or some similar type of professional engineer. This kit is clearly a hobbyist derived kit, and I’m sure the quality of the work is great but no FEA was used, no calculations were done. I wouldn’t put it on my car due to this, but I’m sure many others will. No matter how many times you explain what you are seeing as being possibly inadequately designed for the application, there isn’t going to be a clear answer in response obviously.