Calculating Top Speed

Wondering how much power it will take to get your car up to 200 MPH? Here’s an equation to help you find out. (this information is from August 2001 Sport Compact Car)

Aero Horsepower: Drag x Speed or HP at the wheels

Frontal Area: Amount of Frontal Area (large hood scoops, mirrors and bumper openings add to this and decrease your top speed.

Cd: Coefficient Drag.

Speed: In MPH

Aero Horsepower (wheel horsepower) = 0.000007 x Frontal Area x Cd x Speed3

So using a 2000 Impreza RS for example, lets say we would like to know how much horsepower is needed to go 150MPH. Take .000007 times the frontal area which is 22 and the coefficient drag, in this case 35 times the target speed, 150 mph cubed.

.000007 X 22 X .35 X 1503 = 182

CarFrontal AreaCdHP Needed at 100 mphHP Needed at 125 mphHP Needed at 150 mph
2000 Subaru Impreza RS220.3554105182
2000 Subaru Impreza L210.3247
96
159
1998 Ford Mustang GT22.50.3454105181
1996 Honda Civic DX Hatchback20.50.324690155
2001 Volkswagen Golf GL20.50.314487150
1997 Acura NSX19.20.324384145
2000 Honda Insight20.40.253670120

CarFrontal AreaCdHP Needed at 100 mphHP Needed at 125 mphHP Needed at 150 mph
2000 Subaru Impreza RS220.3554105182
2000 Subaru Impreza L210.32


1998 Ford Mustang GT22.50.3454105181
1996 Honda Civic DX Hatchback20.50.324690155
2001 Volkswagen Golf GL20.50.314487150
1997 Acura NSX19.20.324384145
2000 Honda Insight20.40.253670120