Project Acura RSX, Improving the Stopping Power!

Inconel cone washers under the bolt heads act as a spring locator, taking up the slack between the hat and rotor but still allowing movement to let the rotors float, yet preventing the rotors from making rattling noises, important on a street car. When rotors get hot, they tend to distort in a cone shape due to the heat differential on the side of the rotor that bolts to the hub. The hub acts as a heat sink. When allowed to float on a separate hat, the faces of the rotor heat evenly and stay flat and thus braking forces are applied more evenly on both sides of the rotor with greater force across the face. The brake parts wear better and last longer. The rotors also center better in the caliper and are less likely to create piston knockback. Which is when the rotor knocks the pads back into the caliper, pushing the caliper pistons in and creating a temporary long pedal. The hat of the AeroRotor allows for free airflow between the hat and the rotor with vane shaped passages to help pump air in-between the rotor and hat.  This helps keep heat out of the hub and bearing system.

Our ST40 calipers come with a full set of anti-rattle clips.  Anti-rattle clips are a feature found on all stock cars and their job is to take up all slack between the brake pads backing plate and the caliper. This helps prevent the pads from rattling as the car goes over bumps and reduces pad squeal.  No racing brakes use these.  They are made of corrosion-resistant stainless steel.

Stoptech’s braided steel brake lines do not swell with pressure compared to the stock rubber lines and thus deliver better brake pedal feel. They are designed to pass the stringent DOT whip test so they are certified street legal.  Most non-DOT approved brake lines fail this test.

Our brake pads are Stoptechs versatile 304 compound.  The 304 compound is a great all-around material that is fairly quiet and rotor friendly for the street but can still hold up to moderate track use.  It is a semi-metallic type of compound.

For the rear brakes, we simply upgraded to StopTech’s rear kit P/N 937.40507.  This consists of stock sized slotted rotors and braided steel brake lines with Stoptechs 304 compound brake pads. If this seems wimpy, the fact is that the fastest FWD time attack cars in North America use stock rear brakes!


  1. I’ve noticed that no one makes 2-piece rotors for stock sized rotors. I would have thought the weight savings from the iron hub will still be worth the trouble, but it seems that the market does not demand for it.

    Any insights on that?

    1. Because it would be pointless to offer something like that. Stock rotors are good if you are running stock sized tires with stock type compounds. When you run more aggressive tires and suspension you quickly overwhelm the stock brakes in track use, with aggressive pads, the car might stop but the rotors will become damaged, rapid wear heat checking and warping.

      1. are S2000 rotors the same as RSX? Cause there are 2pc options for that… although same logic applies as to why its kind of a waste of money…

        1. Yup, anyone who is really serious about tracking the S2000 upgrades to a BBK now. It only took a decade of telling people that, ha. The crowd of, “oh, I just bring spare stock rotors because they crack every two track days” is much smaller now.

  2. Would you recommend going to a bigger rear brake on a FR car with more even weight distribution, or do they tend to do well with just a more aggressive pad as well?

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