back bumper Aerodynamics,, big increase?
 

I just cut approximately 29x 4 inches our of my back bumper, obviously leaving the part in front of the gas tank, with a jigsaw,

I have a feeling that I will get a big mpg increase out of this, I'm hoping even 3mpg,

I would think that this part of the car(on most cars) would be the area with the most potential to have drag to remove.. as opposed to the front which is generally aerodynamic already(on most cars) although you can get improvements there too..

I did cut the two pieces symmetrically by tracing the first cut with chalk at equal distances(started cut right where bumper piece starts to curve) to keep the best balance on the car as possible, It appears the rest of the bumper is well attached to the rest of the car, the middle of the bumper is flush to the gas tank almost so I should have no handling problems from plastic bumper pieces blowing in the wind, maybe even handling improvement from this, feels good so far.

Interesting idea. Can you post photos?

lost my ability to be able to track accurate mpg so no results with this

I've heard extending and smoothing out the back bumper is suppose to improve aerodynamics.