THansenite
04-22-2008, 02:11 PM
Whether you are interested in better performance or getting better fuel economy, your car's drag coefficient is an important number that few people know. You can think of it as the lower the drag coefficient (abbreviated Cd), the more aerodynamic your car is. The Cd is used along with the frontal area of your car to figure out how much drag your car has. Since this thread is about the Cd, I'll leave frontal area for another day.
If your car is stock, you can usually find the Cd with a simple google search (the tC's is around .32 if I remember correctly). However, whenever you change aerodynamics, vehicle height, tires, etc., it changes your Cd. Since a lower Cd improves fuel economy as well as vehicle performance, some people may be interested in checking before and after Cd results to see if the new wing they added improves or harms the car's aerodynamics.
Now that I have that out of the way, I came across instructions online for how to measure your Cd without spending stupid amounts of cash to rent a wind tunnel. It is actually fairly simple and involves starting at a predetermined speed, then putting the car in neutral and recording the car's deceleration over time.
Instructions: http://www.instructables.com/id/Measure-the-drag-coefficient-of-your-car/
I know I will be loading the spreadsheet onto my tuning laptop so that I can test my before and after Cd's when I modify my car.
If your car is stock, you can usually find the Cd with a simple google search (the tC's is around .32 if I remember correctly). However, whenever you change aerodynamics, vehicle height, tires, etc., it changes your Cd. Since a lower Cd improves fuel economy as well as vehicle performance, some people may be interested in checking before and after Cd results to see if the new wing they added improves or harms the car's aerodynamics.
Now that I have that out of the way, I came across instructions online for how to measure your Cd without spending stupid amounts of cash to rent a wind tunnel. It is actually fairly simple and involves starting at a predetermined speed, then putting the car in neutral and recording the car's deceleration over time.
Instructions: http://www.instructables.com/id/Measure-the-drag-coefficient-of-your-car/
I know I will be loading the spreadsheet onto my tuning laptop so that I can test my before and after Cd's when I modify my car.