Lots of BBK threads here on IS to review for more info.
Stoptech makes a front BBK kit and NO rear kit for the FX. If you go to Stoptech's site and look for their "white paper" section, they present tech data on WHY rear BBKs don't improve braking performance on the FX - and are for looks only. Here is my particular learning experience, taken directly from the Stoptech website:
This is from Stoptech:
“Stopping power” is an oft misapplied term. What most think it means is more clamping power to push the pads against the rotor with more force, which is only part of the equation. The more correct term is “brake torque”, which is a combination of pressure output of the caliper (controlled by piston size and overall system pressure, i.e. how hard you push on the pedal), the radius at which that force is applied (bigger rotor diameter means more torque if all else is equal) and the coefficient of friction of the brake pads. We are NOT looking to increase brake torque as it will throw off the balance of the brakes. The vehicle manufacturer spent a lot of time and money getting the front to rear balance optimized, and we work to maintain that balance, or maybe very slightly tweak it, which yields the best performance in terms of stopping distance and integration with the rest of the vehicle systems. Adding brake torque to the front (let’s slap on the most pistons we can find) will place too much load on the front tires and likely INCREASE stopping distance and could mess with the ABS. The G-Meter in your butt may think the thing is standing on its nose, which it probably is, but using proper instruments in controlled conditions will show a different result. The over amplified signal from over-sized components will also make the pedal more like a micro-switch, which is also misinterpreted as “Man, I barely touch the pedal and the thing is already into ABS.” Again, the butt G-Meter says “Woo Hoo!”, but is it really predictable and drivable that way? Adding torque to the rear (such as moving the front calipers to the back) can cause rear lock-up and/or adverse ABS intervention and cause the vehicle to lose control. The benefit of a brake upgrade is not dramatically shorter stopping distances, though we do usually see a slight improvement. Buy really good tires and the stock brakes will stop in a measurably shorter distance. What a brake kit WILL provide is much increased heat capacity and better pedal feel due to a stiffer caliper and the addition of stainless lines. The stiffness of the new components does help with stopping distance as the signal from your foot to the tires is shortened due to less loss of efficiencies due to flex in the stock system.
Just to emphasize the point, OE manufacturer’s design all the dynamic control systems around stock components. ANY change to the vehicle may have an adverse affect on how the platform reacts in a panic situation. Sometimes it may be better, sometimes it may be worse. ABS is taking data from the wheel sensors and responding to that data based on how it was programmed with STOCK components. If you dramatically change something, lets say much larger piston volume in the front calipers, as ABS is reading data and trying to correct things, the signals it is sending to the brakes (apply/release/apply/release/apply/release) may not have the expected result due to the increased volume of fluid needed to actuate the brakes and the over amplified brake torque that results. It’s working overtime to figure out if you’re on locking up all 4 wheels on ice or 2 wheels off in the gravel. Add to that aftermarket shocks, wheels and tires, changes to the engine; let’s say part of the dynamic control is to reconfigure the timing to control the engine but the thing is chipped or artificially aspirated… All this is why we stick close to the stock balance on the brakes; we want to do all we can to lessen the impact of our parts on the rest of the vehicle while providing the most benefit in a very controlled manner.
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I love my Stoptechs, but it does bother me I have rear OEM calipers. If I had it to do over again I would probably go with AP Racing because front and rear upgrades cost about the same as the front Stoptech upgrade (with rear rotors, pads & lines).
My advice would be to wait for what you really want - save up. It's worth it.
