Rav4 mods
 

We bought a 2006 rav4 from a friend last summer and I want to do a few mods to get closer to 30 mpg. It has the 4 cylinder and is 4wd. I'm thinking about a belly pan, wheel arch filler(the bristle stuff), and maybe a partial boat tail that mounts in the hitch. I keep the tires at 45 psi, and I just replaced all the fluids with synthetic and the mileage came up to about 25 mpg. I replaced the struts and put new shocks/coils in the rear. I used the 3rd row coils to help with payload/towing. Has anyone done a coolant temp or trans temp mod to help with warmup mpg?

I wouldn't bother with this. Wheel drag goes down (to a point) as the ratio of wheel volume to wheel housing volume increases; adding some open bristles to the wheel arch 1) doesn't affect that ratio and 2) doesn't stop the transfer of air from the high pressure in the wheel housing to the lower-pressure flow along the body anyway, since you don't have a solid surface there.

The belly pan is a good idea. I don't know why manufacturers don't offer a skid plate package to truck and SUV owners that also reduces drag/improves mileage; it'd be an easy way to print money.