Quote:
Originally Posted by BEATO
Just got back from track day at Pocono. After hitting the brakes down from 135mph to 55 it roasted my pads and rotors. SO I was thinking about upgrading to BBK.
If I upgrade to Front 6 Pot 32/34/38mm - 2845 x 2
and keep Stock M3 piston area rear 46mm - 1661 x 2
I get a total area 4506 vs 4487
Stock front bias 63%
Is this worth it? BBK will reduce pad wear and will stop with less effort? Or is it better to upgrade to 34/36/38. Sorry I can't figure out the math on 6 pot lol
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Stock E92 M3 piston area for each front caliper is 2826mm x 2.
A 32/34/38mm x2 piston area will give you a 0.67% greater piston area on the front caliper, and if you keep everything else stock, you will only increase brake torque on the front by 0.67%, whilst increasing pedal travel (slightly softer pedal) by the same amount.
The only real advantage of adding a larger caliper to the stock front disc is that it will provide a much larger pad area, which whilst only making a 0.67% improvement in overall braking force, it will allow the front brakes to absorb more heat overall as there is a greater amount of material to do so. As the brake pad itself is able to take on more heat energy, the front braking system stays cooler longer, and reduces the likelihood of the pads glazing and leaving uneven deposits on the discs that cause judder.
If you're going with bigger calipers on the front, I would encourage you to go with larger and thicker discs, which will increase braking torque whilst also provide much better heat and fade resistance on the track.
*Edit
It's important to add - one of the important elements that define the braking ability of your system, is the coefficient of friction of your brake pads. Street pads are designed to work well from cold, and and are a trade-off between overall braking performance, disc wear, noise and dust. In reality, street pads are pretty rubbish if you want excellent brakes.
Track/Race pads have an enormous tolerance to heat, and far greater COF which mean much greater stopping power, heat resistance, and less pad compression (firmer pedal) but are far more aggressive on discs, are noisy when cold and produce lots of metallic dust which can damage your wheels. Ultimately it's a trade off.