OK. Nothing radical. No slams, no fairings, no radical gearing.
"Is it out of line to expect 2-3 mpg
increase from only adding an open intake and exhaust?"
'Fraid so. I added a 4" exhaust and a Baldwin 2818 filter and got exactly squat for MPG
Here's what works.
I assume since he has a chip, he has a pyrometer. Use the pyrometer to help him avoid jackrabbit starts. Keep the EGT
at 600 or less. This works and costs nothing.
Keep the RPM under 2000. For most stock trucks that means 70 MPH max. If he has 4.10 gears (common on duallies) that means 64 MPH.
Stay with OEM sized rubber. Bigger or smaller hurts MPG
I don't think there is a commercially available chip or tuner that will help him. The only time those help is if your truck is an egregious fuel hog, which his 17 MPG
crew cab is not.
If he can live with one, I wholeheartedly recommend a tonneau cover. Hard or soft - either works. For me in a pretty long rigorous test, a flat tonneau improved my fuel economy by 1.5 MPG
. If he can't hack a tonneau at least always run with the tailgate up.
A 203 degree stat improved my fuel economy by 0.75 MPG
That's the cheap and easy stuff. He might work his way to 20 MPG
But ultimately fuel economy is just another parameter of performance. The same rules apply. You have to do something expensive to get big results.
I would stay away from monkeying with the engine. With the exception of the egregious fuel hogs we hear so much about, these 7.3 engines are sorted out fairly well for economy.
The areas of improvment are gearing (pickups are wildly overgeared) and aerodynamics. Both of these offer lots of opportunity for MPG