I'm thinking about adding a shell to my F150 (Small v8 XLT). Not a full camper-just flush with the cab/snugtop type.

I'm already only getting about 14mpg.

What kind of decrease in mileage can I expect?

 

if you have a need for a topper, get it. but don't buy one to try to increase your mpg. the weight offsets any aero-gains. with a V8 you should breakeven, but may get some increase on a road trip - if you aren't weighted down.

 

I have one that is lightweight, only 68lbs. Still, no help on milage. Have never had one that helps. Only reason I have one is to protect cargo and looks.

 

I guess I wasn't very clear:

I am anticipating a decrease in MPG - I was just wondering how much.

Neverheless, I guess you've answered my question, thanks.

 

i don't think you'll notice much of a change either way.

 

It's a nothing...the aerodynamic benefits are cancelled out by the additional weight.