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[Dave Whitmer]

…when you buy the truck.

I've posted on this before but with $4.25 fuel out there it seems like I need to post again.

Some things improve MPG and some things kill MPG.

Like the Chinese restaurant, here’s a list. Pick and choose what you can handle.

4x4: Big killer of MPG and it forecloses some effective mods. Figure that half-ton of machinery costs you at least 2 MPG vs a 4x2 truck.

Automatic transmission: Another big MPG-killer. It is good for 2 MPG loss vs a six-speed

Dually: It will cost you 1 MPG over a SRW

Crew Cab: It will cost you 0.75 MPG vs a regular cab

Club Cab: It will cost you 0.5 MPG vs a regular cab

Big tires: Anything over 235-85 or 265-75 will hurt. Figure 285s will cost you 1 MPG 305s will cost yet another 1 MPG (this applies to used trucks or dealer-modded trucks only)

Lift: It will cost you 2 MPG vs stock height (this applies to used trucks or dealer-modded trucks only)

Gearing: Very strong effect on MPG
3.55s will get 1 MPG better than 3.73s (all else equal) I understand 3.55s are now standard for 6.4s.
3.73s will get 1 MPG better than 4.10s
My 3.08s (not widely available) improved my economy by 3 MPG over the stock 3.73s

The 6.0 and 6.4 are somewhat less efficient due to EGR and the filter thingy but I would expect a RC 4x2 six-speed SRW with stock tires and the stock 3.73 gears to get 19-20 MPG if driven normally.

All the stuff above adds up.

A CC 4x4 automatic dually with 305s and a lift and 4.10 gears should expect about 9-10 MPG.

There is some variability in this so YMMV.

To add insult to injury, the higher MPG truck will probably set you back $10-12,000 less up front. Even with my exotic drivetrain and aero mods, my truck may be one of the ten lowest-cost trucks in the DieselStop community.

All these numbers square with my experience and what I have found out talking to literally hundreds of guys plus design engineers.

Its your money. You know what you want/need. Get what you will but those numbers outline the unmodded MPG you can expect. The specification sheet is a powerful tool for good MPG from the git-go.