StopTech C43 vs StopTech Trophy Front BBK. Pls help me decide

[Obioban]

Which pads do you run?

OE Porsche pads on the street, Ferodo DS1.11 on track.

https://www.fcpeuro.com/products/porsche-performance-brake-pad-set-ferodo-racing-frp3051w

https://www.fcpeuro.com/products/porsche-race-brake-pad-set-ferodo-racing-fcp1307w

[SQ13]

Great, informative discussions going on. Much thanks.

I guess I should also ask this..what performance benefits would a larger rotor offer? Is it just improved cooling, leading to lower pad and disc wear rates? How significant would the reduced wear rates be? Say 332mm vs 345mm vs 355mm with an appropriate rear setup that maintains a bias close to the ZCP bias (64%F and 36%R).

He was used Pagid Yellows, I was likely on PF01s. Not a huge difference.

Why the C43 kit? If it’s weight, not sure it’s really worth it compared to the impact of improved braking.

For me, I’d consider throwing on the 4 wheels C43 kit to save some weight but I don’t need a parking brake for the TX state inspection. If it needs to be street legal then the ST40/355 kit is kind of a no brainer. You want a 4 wheel kit.


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I feel like an endurance pad vs a sprint pad is kinda a big difference? Lol

C43 seems appealing bc of the weight and price of replacement parts (mainly pads). 4-5 lbs lighter per corner and PFC 11s are half the price. What kind of improved braking would the 355mm Trophy offer over the 332mm C43? I clearly don’t understand brakes very well, so please edumacate me.

I’m in Texas and the car is driven to/from the track. But I like the parking brake when the car is parked on a slope..don’t like only putting the car in gear. I do plan on getting a front and rear BBK, but at this point I’m just not fully informed on the pros and cons between kits of varying rotor sizes. Gotta make a well-informed decision.

[heinzboehmer]

I guess I should also ask this..what performance benefits would a larger rotor offer? Is it just improved cooling, leading to lower pad and disc wear rates?

Yeah bigger rotor means greater surface area, so heat capacity increases. It's not so much that a bigger rotor will lead to better cooling, but more so that it takes more energy to heat up the rotor.

In addition to that, a bigger rotor will also provide more braking torque. Torque (as a scalar) is defined as force multiplied by radius. If we keep the clamping force constant, a bigger rotor (greater radius) will create a greater torque.

Howeever, as gizmo mentioned, BBKs tend to have smaller effective piston areas and thus a smaller clamping force (because it's a hydraulic system, not because the force is related to the surface area of an object). So if you really want to know whether the braking torque will change when switching to a different rotor/caliper setup, you have to do the math and figure out the clamping force for both setups.

Point is, the same caliper on a larger rotor will lead to a greater braking torque, but that might not be the case if you're changing both the caliper and rotor.

Also worth mentioning that the need for greater braking torque is debatable, since the stock brakes can lock up the wheels just fine.

[Nihilation]

Something I noticed while looking at your Instagram photos is that while the rotors are advertised as having pillar vanes, your rotors have the traditional curved vanes. Can you comment on that?

Adam gave me the option to add dust boots to the C43 kit, but maybe he was mistaken. I’ll ask for clarification. Can you expand on maintenance/care of dust boot-free pistons? Debris will definitely be present, so would I just wipe it off from time to time, maybe every six months? Did they say anything on how often rebuilds would be required?

My rotors look like the rotors in every other C43 kit I've seen. I haven't seen anything different to compare against. If I received the incorrect rotors, I'd like to know!

Adam was mistaken about dust boots. When I spoke with Robert at Stoptech, I was assured there is only one caliper design, and it does not support dust boots. He mentioned nothing of caliper rebuilds when I asked about longevity and performance vs the ST40. I was trying my hardest to get him to recommend the ST40 over the C43 for my application (track focused, occasional weekend street) but he did not. I was told the C43 was without question the better caliper, but it would need more maintenance in the form of checking and clearing debris. He didn't say how often, nor did he seem concerned or hesitant about street use. Guess there isn't a suggested maintenance interval -- just depends on the environment.

I've reached out to Christina Lam to get her thoughts on maintenance, pad wear and longevity. Her car is under 3,000 lbs though, so our mileage may differ.

[Obioban]

My rotors look like the rotors in every other C43 kit I've seen. I haven't seen anything different to compare against. If I received the incorrect rotors, I'd like to know!

Adam was mistaken about dust boots. When I spoke with Robert at Stoptech, I was assured there is only one caliper design, and it does not support dust boots. He mentioned nothing of caliper rebuilds when I asked about longevity and performance vs the ST40. I was trying my hardest to get him to recommend the ST40 over the C43 for my application (track focused, occasional weekend street) but he did not. I was told the C43 was without question the better caliper, but it would need more maintenance in the form of checking and clearing debris. He didn't say how often, nor did he seem concerned or hesitant about street use. Guess there isn't a suggested maintenance interval -- just depends on the environment.

I've reached out to Christina Lam to get her thoughts on maintenance, pad wear and longevity. Her car is under 3,000 lbs though, so our mileage may differ.

I have needed to rebuild my stop techs, which see no track use, 3 times. I’ve never needed to rebuild the brembos, which see track and street use.

[Nihilation]

I have needed to rebuild my stop techs, which see no track use, 3 times. I’ve never needed to rebuild the brembos, which see track and street use.

By rebuild, do you mean just replacing the dust boots?

[Obioban]

By rebuild, do you mean just replacing the dust boots?

Dust boots/seals, yes.

[Nihilation]

Check them talk about the C43 caliper during SEMA in 2017. Additional pathways for pad cooling, redesigned piston for less contact on the pad for less heat transfer to the fluid as well has supporting knockback springs. Also a mention of street use.

[bigjae46]

I feel like an endurance pad vs a sprint pad is kinda a big difference? Lol

C43 seems appealing bc of the weight and price of replacement parts (mainly pads). 4-5 lbs lighter per corner and PFC 11s are half the price. What kind of improved braking would the 355mm Trophy offer over the 332mm C43? I clearly don’t understand brakes very well, so please edumacate me.

I’m in Texas and the car is driven to/from the track. But I like the parking brake when the car is parked on a slope..don’t like only putting the car in gear. I do plan on getting a front and rear BBK, but at this point I’m just not fully informed on the pros and cons between kits of varying rotor sizes. Gotta make a well-informed decision.

A pagid yellow isn’t that much different than the PF01s. Yellows have a little less bite and a slightly higher operating temp range.

I get SR34 pads for $210-$230 per pair. If it’s the pad shape I’m thinking about pad pricing is about the same.


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[RazorM]

I have ST40 355/32 on all four corner on my M3. I bought it like that. I use the car on weekend spirited driving and occasional track use. Stoping power is strong I think, using DS2500 now. Do you guys think that this setup is okay, or would you consider changing rears or would not bother?
I have changed the rotor rings for girodisc ones.
I am mostly thinking about it since I see that lot of you guys run smaller lighter rear setups

[mrgizmo04]

I have ST40 355/32 on all four corner on my M3. I bought it like that. I use the car on weekend spirited driving and occasional track use. Stoping power is strong I think, using DS2500 now. Do you guys think that this setup is okay, or would you consider changing rears or would not bother?
I have changed the rotor rings for girodisc ones.
I am mostly thinking about it since I see that lot of you guys run smaller lighter rear setups

How heavy is your car and how long are the sessions you run when you do get out on track?

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[RazorM]

How heavy is your car and how long are the sessions you run when you do get out on track?

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i typically run up to 30min sessions or one Nurburgring lap.
the car is 1460kg/3215lbs now. I will doing some weight loss soon with carbon roof and apex wheels I calculated to get under 1400kg/3080lbs hopefully. It’s more of a Clubsport build than pure track car. But I am trying to loose as much weight as possible without uncivilising the car too much.
I was wondering if I would even feel the difference or is there any performance left in the table with possibly overkilled brake setup.

[arg617]

I've been running the C43 front and rear for just over a year now. Vastly improved feel over my previous stock/comp pack brakes, albeit only pushed during auto-x so far. This is on a weekend/track build (working my way towards a full track setup). The lack of a parking brake tends to be in the back of my mind when I need to park on an incline. Thinking of getting a set of wheel chocks for scenarios where they could come in handy. I like the idea of them being more lightweight than other options I was looking at. For me it was a deciding factor.