So, about them brakes....
We've gone through a few combinations of calipers, pad compounds, and rotors. But, the one thing that has remained constant is the brake master cylinder size. For the Waktins race this year (and all prior races) we were on a 1" BMC (shimmed, not shimmed, and kinda shimmed...). Even with the caliper upgrades, rotor sizes increasing, etc, the biggest complaint (if we are to split hairs) has been about feel and modulation.
So, we decided to [subjectively] test the old argument of whether a larger or smaller BMC will aid with feel and modulation. The general consensus is that usually a smaller BMC aids in modulation because it makes for longer pedal travel with a smaller amount of pedal force for a given system pressure. That longer pedal travel gives you more 'resolution' of sorts through the pedal stroke. Vice versa for a larger BMC.
I've always been in the "you don't modulate your brakes based on pedal travel" camp so I've been skeptical of going smaller. But, after conversations with PFC and a few others, I decided to try the 15/16" BMC for the NJMP race.
The result was just 'meh.' I could definitely feel the longer pedal travel when compared to the 1" BMC, but the modulation and feel was similar to the 1" BMC to me. My co-driver thought it was worse.
Next up was the 17/16" BMC that we just ran at an open test day last Friday. No other changes on the car except for that. It was a unanimous decision; we have a winner! Everything about the change was positive. Higher pedal force threshold to lock up the brakes, shorter travel, easier to modulate. It really addressed most of our complaints (until we get bored and try to find more) about our Frankenstein braking system.
Not only that, it also confirmed my suspicion about the smaller BMC provides more feel/modulation mantra. At least in my case.
My current setup which is the best the brakes have felt yet all around. And to top it off, they don't squeal. Huge fan of the PFC compounds so far:
- B13 Sentra non-abs booster (this is important)
- 17/16" brake master cyclinder (not shimmed)
- Stainless steel brake lines
- Front (Defsport hats w/ Core4 radial bracket)
- Wilwood FSL6R Calipers (4.04 in^2 piston area)
- 12.72" x 1.25" Wilwood Spec37 HD slotted rotor rings
- PFC 11 Compound
- Rear (Core4 rear BBK)
- Wilwood Forged Narrow Dynalite Calipers (1.98 in^2 piston area)
- 12.2" x 0.81" Wilwood Spec37 HD slotted rotor rings
- PFC 97 Compound
If this was a track day only/TT type car running R-compounds or slicks, I'd get more aggressive PFC compounds.