Steel Front Bumper
 

I have been driving without a front bumper for the last couple of weeks and I have been noticing that it is impacting my fuel mileage. I only average about 21 mpg now, and only around 22-23 mpg on the highway. I am wondering on how much of an improvement that this bumper that I purchased will have over no bumper at all. I will be getting the front hitch receiver however I will be buying a plug for it. I will also be welding a hoop on it for extra protection. For those of you who don't know what that is, I included a picture of one. It is the tube steel that is welded on to the bumper. The one I will be making will not be above the hood, but will look similar. The other difference is that the entire hoop will be made of tube steel.

Here is a better view of a hoop:

I am sure having a bumper there will aerodynamically be better than no bumper, weight will be a reduction for City MPG possibly.

Have you considered mounting sleeves down in the bumper and making the hoop removable. Suppose you're using inch and a half OD tubing for your hoop, you could get some 1/8 wall inch and 3/4 and weld it in the bumper flush with the top and have two pins where you can slide the hoop in and out and pin it.

Just don't put a winch on it.

how much improvement
 

I suspect that you'll see very little in the way of fuel economy,unless the entire nose of the JEEP were sealed with a wrap-around airdam.There's too much torture chamber still exposed to the air.Total turbulence.
The JEEP Liberty's or Cherokee's front would be an example to aspire to.Get all the air around or under the naughty bits.

I'm not sure if a removable hoop is feasible as the bumper only extends like an inch out from the grill. It is a good idea though and I'll know better when my bumper is built.

I'm not sure about the strength of that setup either, which is very important for what the function of the hoop is.

I'm sure a winch is terrible as far as aerodynamics is concerned. I won't get one.

I'm thinking some carefully thought out skid plates will help out a lot, especially because I'll be lifting the Jeep a bit more. I'm not sure if there's much else I can do to the front end but I'll need to think that through once my bumper is on.

Any basic suggestions for skid plates?

It depends if your are protecting components or building rock sliders. You should be able to fabricate full belly sliders that are very aero. Just remember to make them removable for maintenance. Our newest Jeep Cherokees at work are very aero underneath but they do not protect anything just aero plastic panels.

I am getting close to starting on mine for my 4runner they are going to be bent 1/4 aluminum plate down the center where strength is needed. Quarter aluminum is what I found cheap on craigslist...

I am planning on lighter materials in less demanding locations.

Post pictures of you can!

One thing I'm noticing as I'm installing my lift is that the gas tank probably catches a lot of air. I think I could gain a lot by raising it into the cargo area.

skidplates
 

From Hucho's research,the skidplates will be the highest drag configuration.No aerodynamicist would recommend that route.
I suppose the smoothest,most airtight curved bellypan-ish plates would do the minimum damage to airflow.