"Assuming a brake system is properly balanced, strong enough to lock a wheel, and yet not hot enough to fade, the stopping distance is largely a function of tire traction, not brakes. Think of it this way: All brake systems, stock and aftermarket, are able to activate the ABS, so how could a stonger brake shorten a stop? Eric Dahl, a brake engineer from Brembo, put it this way: 'Don't expect the brake kits to stop you sooner, but expect the 20th lap to feel like the first.'"
The results are of a series of 90-0mph stops with the results averaged. This test is far more taxing on the brakes then anything a street car would ever face. Differences from the average of four tests exagerate the distace of the stock brakes from a single stop. From a single stop the Hawk pads netted a distance decrease that was not dissimilar to the expensive full race systems:
Stock brakes 340'. Note that the stock brakes could no longer perform after 4 stops. Stock WRX brakes are a two peice, two piston caliper design.
Stock brakes with Hawk HP+ pads 316'. (I believe these results are also averaged over 4 stops)
StopTech 297'. Note that the StopTech brakes have slotted rotors, four piston block brakes and custom brake pads. (I believe these results are averaged over 25 stops, but that this didn't drastically alter the distance comparison that we want to look at. I no longer have my hard copy of this comparison, so I cannot produce the numbers from each of the 25 stops) The StopTechs achieved the best results on this test when compared to the two Brembo and Prodrive systems.
When determining if one should purchase slotted or drilled rotors for their street vehicle, consider this extreme test with multithousand dollar systems vs. stock brakes with Hawk pads. The difference is between the two solutions is ~5% braking distance. How much of this difference would you realisitically attribute to the superior pads and calipers? Given the performance of the Hawk pads over stock, I would suggest the vast majority of the credit is due to these two components. How much of the measurable difference can be attributed to the rotors? Likely very little. This confirms the concensous by experts is that for the street, the reduced area of drilled rotors may even increase stopping distances and that slotted rotors have no positive effect either.
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