Quest for mpg

Hello all, first post here. I have an 05 780 with d12d. Have replaced cac, boost sensor and turbo avg 6.2 mpg. This is what I'm thinking, gutting the preheater on the intake side to increase air flow as well as eliminating epg and restrictor in s-pipe and coming directly off turbo with exhaust piping to eliminate back pressure. Also installing full flow muffler. Thoughts or concerns?? Input greatly appreciated!

 

i run mainly mid atlantic and southeast, alot of rolling hills for the most part and my weights are all over the place but more times than not it's in the 35 to 40k range all dry box. my trailer gap is as close as i can get it and tire pressures are checked daily. i run 115 in the drives and 112 in steers, a little rougher ride but i understand the higher pressures reduce the chance of a failure and reduce rolling resistance. all of my calculations are done on paper because there are too many variables in the system to go by the dash readout, but i will say that the numbers are usually within .2. i had the preheater apart 2 days ago just to see what the inside looked like, wish i had taken pics to share. there is an electric coil that takes up approx. 20-25% of the space. i was just figuring that if i gutted it then it would allow for better air flow, same principle as reducing exhaust restriction. i dont really need a preheater, i've had 2 other trucks both with detroits and neither had anything like that. never had a problem with cold weather starting. i believe it is intended for those in the super cold climates such as up north and the scandinavian countries that routinely see sub freezing temps, either way its optional equip IMO.

 

I've never thought of that, have to give it a look see!

 

That's what I do now and keep my avg cruise speed right at 60...I'm just kinda brainstorming trying to come up with a few ideas to improve mechanically.