Hello everyone!
 

I've been watching this site for a while now, for about a month. I am happy to say that I have improved my gas mileage(mostly city) from 18... to 25! Just from changing how I drive! I have also found that on the highway, if I keep it below 65, I can get 29MPG highway! That's 4MPG above EPA estimates. I am interested in how much more I can improve it. By the way, I drive a 2001 Mercury Sable LS with the Duratec engine. I am open to any mods that don't look ridiculous or are impractical for a daily driver. The car appears fairly aerodynamic, but I can imagine an upper grill block and an undertray would help tremendously. However, I am not sure how to construct either. I am also open to engine modifications, but I cannot remove my ac compressor because my girlfriend would not like that( I wouldn't mind, I never use it anyway.) My goal would be 35MPG highway, which I know is feasible since other Sable/Taurus drivers report 35MPG highway stock( I don't see how???).

Welcome to ecomodder !

A grille-block can be made quite easily with tape or some plastic plate - many use coroplast, the stuff election or real-estate signs are made off.
You can paint it black or your car's body colour, then put the block on the inside of the grille, so it doesn't really show.


An undertray or belly-pan is a bit more involved to make, as you need to be able to get underneath the car to install it.
Fixing it to the car takes some ingenuity. You'll have to see what's there, and how you can use it.

Some members use CAD to make one : Cardboard Aided Design ;-)
Cut and glue to shape, then when you're happy with the fit, transfer the shape to more plastic or even aluminium sheeting.