Improving fuel economy for the 1991 200q 20v

alan cordeiro alancordeiro at
Fri Mar 4 22:09:52 EST 2005

Energy used to overcome drag is proportional to the square of the velocity.
(power used is velocity cubed...but gas used depends mostly on energy)

Drag force,   Fd = A + BV + CV^2   

and energy is Fd * distance.

Unfortunately at low throttle angles the engine is running at lower
volumetric efficiency, overall power conversion efficiencies run
way below Carnot cycle theoretical, probably in the in the 
10-15% range, so going VERY slow can also be counterproductive

> You didn't mention anything about aerodynamics. At highway speeds, the 
> drag force is quite significant. Hard to say what would improve the 
> aerodynamics of our cars....but it could be improved upon. Since drag is 
> proportional to the cube of velocity (the power to overcome drag 
> anyway), cruising at 60 mph will likely get you better fuel economy than 
> cruising at 80 mph.

More information about the 200q20v mailing list