Interesting experiment I just performed

[fumesucker]

I ran some baseline aerodynamic drag tests on our 94 Altima today in preparation for doing some aero mods like blocking the grill..

I used my digital camera in video mode to record my speedo as I coasted down from 70 mph indicated to 65 mph indicated (my speedo reads almost exactly 10% fast since I have smaller diameter than stock tires).. I would like to have used a greater speed differential but finding a flat straight road here is quite difficult.. I had to drive nearly ten miles to get to the 3/4 mile stretch I used.. And then I had to wait for traffic to clear.. I made three runs in each direction and averaged the results.

I then counted the frames on the resulting video (15 FPS) and came up with a time for the coast down.

Anyhoo.. I came out with a deceleration of 1.49 feet per second squared..

Then I used the curb weight of the car and added my weight and then calculated the force applied to the car to decelerate at that rate and came out with 139 pounds..

Further calculations show that works out to about 22 horsepower to maintain 60 mph..

Then I went to this website:

http://www.fbody.com/calc.htm

And used a fuel calculator there to discover that 22 hp takes about 1.833 gallons of fuel per hour..

This works out to 32 mpg.. Which is pretty damn close to what I get at 60 mph..

Pretty cool, I think.. It definitely gives me an idea that I'm in the ballpark as far as my calculations go..