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The diffuser is canted upwards at the proper 7 to 10 degree angle to keep the air flow attached. Since the angle is actually closer to 10 degrees, Brian added strakes to the plane of the diffuser. These strakes act like vortex generators and help keep the flow attached improving effectiveness and allowing the diffuser to work at lower speeds.
The front of the diffuser bolts right to the chassis swaybar mounts. Super solid! People often forget that properly designed aero generates a lot of force and has to be mounted accordingly.
The bottom of the FR-S is pretty smooth so we expect the diffuser to be effective. It is about even with the bottom of the lower control arms at ride height. In any case, the Afterhours diffuser looks really good on our non show car. Our 265 meats really fill the wheel well!
Perhaps the most important part of our aero package to date is our front splitter. Splitters are very effective and simple aerodynamic devices that create a lot of downforce with little drag penalty. A splitter works by trapping airflow as it stagnates or loses velocity at the front of the car. As the air slows down, the pressure increases due to compression by the car's relatively blunt front end as it passes through the air. The splitter captures this high pressure zone on top of its body. Our splitter can generate well over 100 lbs of front downforce and is needed to balance out the rear wing.
Air is managed pretty well under the FR-S so the splitter will be very effective. You can see the metal and plastic covers that improve under car airflow.
