Increasing Performance, Efficiency and Style - Ultimate Efficiency

The same goes for aerodynamics; if we have two vehicles producing the same amount of power, one shaped like a bread truck and the other like a rocket, we know which one will reach a higher top speed. The more aerodynamic vehicle requires less energy to overcome wind resistance, and will also become the more fuel efficient of the two, driven at the same speed as its boxy brethren. Experts estimate that a two-percent improvement in a vehicle's aerodynamics (as gauged by drag coefficient) can improve its fuel economy by approximately 0.2 mpg, in mixed driving. Expect that figure to more than double at freeway speeds, where as much as 60 percent of the energy a car puts to the ground is lost to wind resistance. Improving a vehicle's aerodynamics means more of its engine's power can be put toward increasing acceleration at speed, attaining higher top speeds, or decreasing fuel consumption at highway speeds.

Decreasing static and rotational mass, and decreasing drag (improving aerodynamics) increases downforce and braking performance, improves handling, elevates top speeds, decreases acceleration times, and increases power and torque output. And as long as we fight the temptation to accelerate quicker and drive faster, fuel efficiency is also increased.

In the next installment, we'll be applying the logic of increasing performance and efficiency to the engine and drivetrain, in the quest for big power with reduced fuel consumption. We'll also discuss gearing, driving techniques, and improve upon modifications made thus far to increase the all-around efficiency of our Integra, as well as add some race-day mods to turn it into the dualistic commuter/track machine only the imports seem to pull off in style.

• The term "drag coefficient" is the classic standard of measurement used to identify a vehicle's wind resistance. In short, vehicles that are tall and boxy are the least aerodynamic, and are rated with higher numerical values (like the Hummer H2, at 0.57), while shorter, narrower, longer vehicles with smooth transitions and less frontal area are more aerodynamic (like the Nuna 3, at 0.07). The Integra's 0.33 drag coefficient beats out the Lamborghini Countach (0.42), R32 Skyline GT-R (0.40), Ferrari F430 (0.34), and even a car called the SSC Ultimate Aero (0.35). Still, it has room for improvement. An FD RX-7 slides in at 0.29, a Honda Insight at 0.25, and even the Toyota Sienna minivan beats it, at 0.30.

• One of a car's more significant areas of drag is the area between it and the driving surface. Lowering a car decreases the amount of air traveling underneath it that can cause drag with points like the wheels, control arms, exhaust, etc. According to Mercedes-Benz, "Lowering the ride height at speed results in a three-percent decrease in drag." Our Integra's aggressive BC Racing coilovers keep the car from bouncing over uneven surfaces, that would otherwise allow an influx of air under the car. Their decreased travel also limits changes in toe and camber over uneven surfaces, reducing rolling resistance slightly.

By Luke Munnell

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