Cooling the Acura NSX supercar

By Christopher A. Sawyer
The Virtual Driver

(June 13, 2016) In order to gain superior downforce and efficient cooling, Acura NSX aerodynamicist and Cooling Project Leader Thomas Ramsay and his team used computational fluid dynamics simulations and wind tunnel testing of 40 percent scale models to optimize the car’s shape.

The results gained via CFD simulation and testing in Honda’s Ohio wind tunnel were validated with full-size models at Honda’s moving ground plane wind tunnel in Tochigi, Japan.

Front-to-rear aerodynamic balance was determined to be of primary importance, with the rear downforce three times greater than the front.

This ratio was determined to provide optimal distribution for both high-performance and daily driving. The rear diffuser, rear spoiler and taillight slots work together to generate a significant amount of downforce while managing the drag created by the NSX’s aerodynamic wake. By fine tuning grilles, slots, ducting and exit points, Ramsay and company were able to avoid the need for active aerodynamic bodywork.

Up front, the air follows optimized exits that take into account total airflow, low drag and maximum downforce. It is directed along the vehicle to achieve a flow pattern that feeds the engine air inlets. The vents in the front fascia are positioned to reduce turbulence and aerodynamic loss around the front wheels, and work with those located in the front fenders to stabilize the airflow along the side of the car.

The floating C-pillars feed the side intakes, which channel air to the engine intake, engine bay and intercoolers. They also smooth and channel the rest of the air flowing across their surfaces to the rear deck to increase downforce.

The NSX has seven primary heat sources — the 3.5-liter V6 engine, two turbos, a nine-speed dual-clutch gearbox, the power distribution unit and the twin motor unit — whose temperatures are managed via 10 heat exchangers. The front cooling system includes the engine radiators, twin motor unit cooler, air conditioning condenser, transmission cooler and the heat exchanger for the hybrid system’s power distribution unit.

In the rear, air flowing over the roof and hatch glass feeds air to the clutch cooler and increases airflow through the engine bay.

The Virtual Driver