“Roof bump” camper shells and MPG

I just took an A.R.E. aluminum utility shell of my 2011 2.3L reg cab and it is performing WAY better on MPG. The shell was the kind that is 2-4” higher than the cab and has an integrated lumber rack as well.

Lesson learned: aerodynamics are a big deal.

So, I’m considering a lower profile aluminum/utility or fiberglass camper shell. I’m curious, has anyone experienced a noticeable difference in MPG between the camper shells that are at the exact roofline of the cab vs the “roof bump” camper shells that start off at the cab height and then raise up gradually towards the tailgate?

Either way, I’ll be looking for a shell that makes a smooth transition between the cab and the camper from now on, at least.

 

Is it one of the sloped versions or flat front? Did you try using a wind deflector? Just curious if it made any difference.

 

Flat-front, and I was in the process of building a wind deflector but once I took it off, the performance was so much better that I’m more motivated to find other options now.