|
Welcome to the site.
We recommend first reading the 65+Modding tips and then the 100+ hypermilling ideas. I bet you can find a few in each that 1) are low budget modifications and 2) convince your fiance to learn.
You also have to think about where the car is driven most of the time. If it does most of its miles on the highway then work on aerodynamic mods. If it just drives from one stop light to the next then see what you can do to make it lighter.
Most of us are not big fans of the aftermarket "booster" products. Some here have tried them and run A-B-A tests and not found any increase in fuel economy. Most of the products are attempting to increase power out of the engine. More power does not mean better fuel economy most of the time. The best mods are ones that lower the drag of the car, lower the internal friction of the moving parts, or help the engine run more of time in its most efficient operating region.
Some of the largest gains are when you buy a ScanGuage or similiar product. This shows you what your gas mileage is at all times and other information about your engine. Just having your gas mileage displayed trains you to drive more "gently".
Good Luck
|