Increasing Brake Thermal Capacity.
The OEM Brembo brakes on the STi are very capable. Simply putting high-temperature brake fluid in will be all that is required for a track day at stock power levels. Pad fade on the OEM pads will be apparent at a track like Laguna Seca; however, this can be fixed by swapping over to a track day pad that can handle the higher thermal load. Even with high power output, in most cases, upgraded pads, fluid, and rotors are all that are required to handle track duty. So why did I shell out the money for the AP Racing Competition Brake Kit (Front CP8350/325)? Because they are ****ing awesome, and I wanted them! Advertising 15 lbs of unsprung weight savings, a widely proliferated pad size that offers a wide range of available compounds, and competitive replacement part prices don’t hurt either.
Weight Savings.
One rotor, caliper, and attaching hardware came in at 23 lbs. Keep in mind that the scale is for corner balancing a car, so it’s built to weigh thousands of pounds, not ounces. Therefore I wouldn’t be shocked if it was off by +/- a pound. The OEM equipment with a DBA 4000 series rotor weighed 30 lbs. Therefore, I show 7 lbs saved on each corner for a total of 14 lbs of unsprung weight saved. Considering the scale used, I’d say that’s a positive verification of AP Racing’s advertised 15 lbs savings.
You’ll notice I did not weigh the mounting bolts with the OEM hardware, and the old pads are in the OEM caliper. I didn’t weigh the new pads with the new AP equipment. This was an error I caught later. The old pads were less than a pound due to being worn down, and were roughly about the same weight as the mounting bolts which aren’t on the scale. All things considered the weights are a fair comparison and the savings is accurate to within one pound.
Lots of Pad Options.
It took some digging to find a pad compound that is tolerable for occasional street duty. Carbotech offers their 1521 street compound in the correct pad size and have similar noise and dust features as the OEM pads. They are perfect for getting you to and from the track.
