brake upgrade conundrum

[DRLane]

Originally Posted by Captain Caveman

Good question, let me explain. 99% of the OE retrofit kits that I have seen banded about for our cars, use easily available Brembo calipers that are not optimal for our cars in terms of piston area and they are mostly compromised in some area or other. They therefore:

- Are primarily marketed at ppl caring more about looks than performance
- Use cheap, easily available, often heavy calipers without much thought into piston areas, pedal travel/feel or master cylinder compatibility
- Use caliper designed for much thicker discs, but are marketed for stock discs
- Expect you to retain stock discs, which are a weak point (heavy, not very tolerant to abuse) and the 1st thing I'd change
- Are mostly front kits, with no attention to the rear

I want a kit that is 100% equivalent to the Brembo GT kit, with no compromise, but without the silly price tag. A caliper is a VERY simple piece of engineering, with very little to it. Brembo are just using their brand position to hike up their prices in a near monopoly position.

Through months of research, calculations and refinement, I have therefore now specced a kit that:

- Uses high spec Brembo calipers from a high end sports car
- Upgrades both the front AND the rear brakes
- Has the same piston area and F/R bias as the Brembo GT kit
- Uses larger 2-piece discs all round
- Doubles the available pad area compared to stock
- Requires no butchering/machining of the caliper body to fit
- Is HALF the price of a new Brembo GT kit with no downside or compromise

Hope that helps understand the value proposition and benefit.

Thanks man! Based on your previous posts I figured there was some secret sauce.

[Captain Caveman]

Originally Posted by DRLane

Thanks man! Based on your previous posts I figured there was some secret sauce.

No real 'secret sauce' mate. Just a bit of hard work and common sense. Brake manufacturers like to dazzle us with pizazz and tech specs, but the reality is, the likes of Brembo sell their calipers to car makers for a a few hundred dollars, and then try to charge us $1000s in the aftermarket for pretty much the same thing.

The Brembo GT caliper design (or near identical) is available as OE spec on Audis, Mercs, Alfas, Maseratis, Corvettes, Chevies, Fords, Astons, GTRs, Lambos, Ferraris and a good many other vehicle brands.

We know the piston area of the E92 M3 and the relative piston sizes of each caliper, so it just takes a bot of homework to find OE Brembo calipers with the same piston sizes with radius mount that don't require any messing around with CNC machining etc.

[roastbeef]

You didn't initially mention rotors. What rotors are you planning on using?

[Bartledoo]

for only 3-4 track days per year get the FCP stuff with lifetime replacement, unless you find a very good deal on a used BBK.

[Captain Caveman]

Originally Posted by roastbeef

You didn't initially mention rotors. What rotors are you planning on using?

I am having some 2-piece rotors with alloy bells made up.

- Floating 390mm x 34 front
- Fixed 380mm x 30 rear with steel drum brake insert

I'm a while off with a prototype yet, but will post pics and more info once I have everything nailed.

[roastbeef]

Originally Posted by Captain Caveman

I am having some 2-piece rotors with alloy bells made up.

- Floating 390mm x 34 front
- Fixed 380mm x 30 rear with steel drum brake insert

I'm a while off with a prototype yet, but will post pics and more info once I have everything nailed.

if you have the ability to make custom rotors/hats, why not create an oem direct fit rotor that addresses the weaknesses in the oem system? the rotors don't need to be 390mm, and the parking brake doesn't need to be steel.

[pbonsalb]

Coleman makes custom rotors.

[Captain Caveman]

Originally Posted by roastbeef

if you have the ability to make custom rotors/hats, why not create an oem direct fit rotor that addresses the weaknesses in the oem system? the rotors don't need to be 390mm, and the parking brake doesn't need to be steel.

Fair point. That could be an option, certainly. One thing at a time though.

I am looking to make a solution that provides a noticeable performance increase and that has sound engineering, both on a par with the big name BBKs, whilst giving buyers the 'bling' that many are looking for with the visual impact of a BBK. You don't need a 390mm front disc, but it fits under stock 19" wheels and certainly won't do any harm, apart from adding a tiny bit of extra weight.

[DRLane]

Originally Posted by Captain Caveman

Fair point. That could be an option, certainly. One thing at a time though.

I am looking to make a solution that provides a noticeable performance increase and that has sound engineering, both on a par with the big name BBKs, whilst giving buyers the 'bling' that many are looking for with the visual impact of a BBK. You don't need a 390mm front disc, but it fits under stock 19" wheels and certainly won't do any harm, apart from adding a tiny bit of extra weight.

But if you're making it for tracking performance, no self respecting e9x runs 19s... :seesaw:

If not, then why wouldn't folks just use the existing repurposed solitons? They already solve the street / bling.

[Captain Caveman]

Originally Posted by DRLane

If not, then why wouldn't folks just use the existing repurposed solitons? They already solve the street / bling.

Because the are pretty ill thought out and require some sort of compromise in order to fit.

I can of course offer smaller diameter rotors no problem - I will let the customers decide what they want.

[pbonsalb]

Originally Posted by Captain Caveman

You don't need a 390mm front disc, but it fits under stock 19" wheels and certainly won't do any harm, apart from adding a tiny bit of extra weight.

While I would stick with 380 or maybe 370 to allow 18 inch wheels to work, it is possible that the kit with 390s won’t add any weight. My Stoptech ST60 380mm front kit weighs about 1 lb less than the stock front brakes.

[GeorgeA]

Originally Posted by 911r

Not bad--did you feel like the setup was lacking in any way? Awesome to hear that they didn't fade to a major extent or anything like that.

Yea I was surprised. Just to compare:

Last time I was running better tires (RE-71R, lapping 1:24s) with Stoptech Sport pads and those were done after around 10 laps (they disintegrated).

This time around, the DS2500 was better at temp, i would experience some fade after that many laps but nothing crazy. Also, at that point the car and tires are SO hot that I would have pulled off the track anyways. First time tracking with Hankook RS-4’s and those were a bigger issue than the brakes.

Overall, positive experience with them. Only negative is the noise on street driving. It comes and goes, might have a day of quiet driving followed by a day of loud train-like noises.

[pbonsalb]

Isn’t that one of the reasons track guys change yo a BBK? There are no pads that are great for both street and track use and it is a pain to change pads with the stock calipers. A BBK with removeable bridge makes lad changing easy so you can use great street pads on the street and great track pads on the track. Of course better pedal feel from the additional pistons in the caliper and better heat dissipation from the thicker and better designed, true 2 piece and perhaps larger diameter rotor also reasons.

[Bartledoo]

I actually have no problem with my PFC11 street pads

[roastbeef]

Originally Posted by Captain Caveman

Fair point. That could be an option, certainly. One thing at a time though.

I am looking to make a solution that provides a noticeable performance increase and that has sound engineering, both on a par with the big name BBKs, whilst giving buyers the 'bling' that many are looking for with the visual impact of a BBK. You don't need a 390mm front disc, but it fits under stock 19" wheels and certainly won't do any harm, apart from adding a tiny bit of extra weight.

well, forget about performance with a 390mm kit, no track guy is going to be excited about that. its going to be heavier than oem and limit wheel choices. nobody runs 19's at the track by choice.
my ap racing kit is 355mm, its 5mm smaller than oem, but weighs 10.5 lbs less per corner, for a total unsprung and rotating weight. big size isn't better.

Originally Posted by pbonsalb

Isn’t that one of the reasons track guys change yo a BBK? There are no pads that are great for both street and track use and it is a pain to change pads with the stock calipers. A BBK with removeable bridge makes lad changing easy so you can use great street pads on the street and great track pads on the track. Of course better pedal feel from the additional pistons in the caliper and better heat dissipation from the thicker and better designed, true 2 piece and perhaps larger diameter rotor also reasons.

pad swaps are still sort of a pain in the ass, its not as glamorous as they make it seem. its not like putting toast in a toaster. the only benefit is you don't have to cradle a 15lb caliper once you get it off.
the bridge supports have tight tolerances and can be hard to slide in and out once they are warm and baptized in brake dust. then, you have to spread six pistons at the same time, and while you slide in one of the pads, a piston or two on the other side usually start making their way back out (anti-knockback springs doing their thing) and you have to spread the pistons again.

[pbonsalb]

Originally Posted by roastbeef

my ap racing kit is 355mm, its 5mm smaller than oem, but weighs 10.5 lbs less per corner, for a total unsprung and rotating weight. big size isn't better.

I thought you had a Stoptech ST40 kit?

[911r]

Originally Posted by Bartledoo

I actually have no problem with my PFC11 street pads

Stock brakes otherwise? I think we have similar suspension setups, I'm just not running aero.

[roastbeef]

Originally Posted by pbonsalb

I thought you had a Stoptech ST40 kit?

no, i have the essex ap racing cp5060 (front) and cp5040 kit (rear). the combined kits get rid of 37 pounds of weight in the braking system alone.
i was sold on the kit after talking with jordan yost at a track event. he had just competed in the 25 hours of thunderhill with his e92 m3 equipped with these brakes. he said he never had to worry about the brakes.

i often refer people with budgetary constraints to the st40 kit. its a good value for what you get, and you can rotate pads. might not seem like a lot, but i'd absolutely love to be able to rotate pads.

[Bartledoo]

Originally Posted by 911r

Stock brakes otherwise? I think we have similar suspension setups, I'm just not running aero.

Nah full PFC bbk. Pretty sure the stock brakes would burst into flames if I tried to run them lol.

[911r]

Originally Posted by Bartledoo

Nah full PFC bbk. Pretty sure the stock brakes would burst into flames if I tried to run them lol.

Hah! Yeah I would have been incredibly surprised

[Bartledoo]

Originally Posted by 911r

Hah! Yeah I would have been incredibly surprised

Yea I was getting bad pad fade after a few laps when I was 6 seconds slower lol

[Captain Caveman]

Originally Posted by roastbeef

well, forget about performance with a 390mm kit, no track guy is going to be excited about that. its going to be heavier than oem and limit wheel choices. nobody runs 19's at the track by choice.
my ap racing kit is 355mm, its 5mm smaller than oem, but weighs 10.5 lbs less per corner, for a total unsprung and rotating weight. big size isn't better.

Don't worry. I'm having the rotors/bells made to order, so can be made in whatever size the buyer requires. They will be available in 390/380/370/360/350mm. Hope that satisfies your concerns.