While looking at new cars, I notice there’s an option for an Aero package that lowers the coefficient of drag from 0.29 to 0.28, almost a 3.5% drop in specs.
It costs $550.
My question is, is it worth its value in gas savings over say a 100,000 mile period of an average person owning the car (average city/highway driving)? or how significant is the coefficient of drag on gas mileage?
gas mileage is listed as 19mpg city/26mpg highway.
Car is a G35 6MT Coupe for reference.
Energy required to overcome air drag is proportional to drag coefficient (asuming everything else is constant). So in the best-case scenario, you’re going to save 3.5% of fuel. At 26 mpg, that’s 135 gallons over a 100,000 mile period. It’s not going to pay for itself unless gas price goes up to $4/gallon.
In reality the savings will be smaller, because air drag is not the only source of drag. And the aero kit probably adds weight which may negate any aerodynamic benefit.
And keep in mind that speed has a much greater effect on air drag than drag coefficient. Energy required to travel a given distance is proportional to drag coefficient, but proportional to squre of speed. So if you want to improve fuel economy by 3.5%, just drive 1.7% slower.
Finally, if it just said “0.29 to 0.28” I’d get suspicious. You’re assuming that means 0.290 to 0.280, but it may well be 0.286 to 0.284.