I recently picked up a 98.5 2500 2x4 short bed that had some money thrown at. I decided to take it to the next level and do everything possible to get 30 MPG when empty at 65 mph. I live in a 5th wheel camper and travel for a living, so diesel costs add up!

Please give me your best ideas to improve MPG.

Here is what I've done so far.

• Front End Aerodynamics on the grill & lower bumper shroud & tonneau cover ( Considering a belly pan underneath )

• RV 275 Injectors with 7 holes ( Are there better injectors out there for economy ? )

• 19.5" tires that leave me at about 1750 RPM @ 65 mph with 3.55 gears

• Quadzilla with an economy tune ( Hoping to get a custom tune when all hardware is done )

• 205 degree thermostat ( higher temp leads to more complete combustion ) I have an upgraded radiator for pulling

• Borg Warner K27 turbo ( 18 cm^2 exhaust outlet volume is 50% larger than a stock HX35 at 12cm^2 thus reducing back pressure )

• AFE Bladerunner GT Series intercooler 3" thick ( denser air burns fuel more completely )

• Full Lock Up Torque Converter

• 15" Dual Electric Fans ( Stock fan clutch eats 20+ horsepower according to some estimates )

I'm looking for a used gear vendors overdrive as that would get me to 1500 RPM @ 65 Mph

What ideas do you have ?

Edited 21 hours ago21 hr by Honestbest333

You listed "19.5 tires". Do you mean 19.5 wheels? If so, that could be an issue, wheel/tire combos like that create a lot of rolling resistance.

@Mopar1973Man has done a lot of work with his 2001 2500 in the way of hyper mileage. Hopefully he will see this and chime in.

@Titanium , oops. Tagged your "old name"

Old habit lol

15 hours ago, Honestbest333 said:

1. 19.5" tires that leave me at about 1750 RPM @ 65 mph with 3.55 gears

That would be a problem that would make your final ratio too tall andf hurt MPG's. Optimally I've found is being between 3.55 to 3.73 for final ratio after tires are figured in. Like myself I dropped the 265/75R16 and then swapped in the 245/75R16 which changed my final ratio to 3.69:1 at the tires this produces way better torque and pulling power. My out right best was crossing all of Washington state from Seattle WA. to Lewiston ID was 300 miles I barely burned a quarter tank. Optimally the final ratio should be kept bewtween 3.55 to 3.73 for what you are doing with towing. Pay attention rotational mass counts too so heavier tire will hurt your MPG number quick!

15 hours ago, Honestbest333 said:

Borg Warner K27 turbo ( 18 cm^2 exhaust outlet volume is 50% larger than a stock HX35 at 12cm^2 thus reducing back pressure )

Super simple just build a advanced tune on the Quadzilla I can unwind a turbo really easy. Retard adds boost to the power number. It's a balancing act to get the power out of it. The other tidbit I'm running nothing more than a stock HX35W and still getting mid 20's easy. HX35/40 Hybrid turbo (60/60/12) that did really good for MPG being it was just a bit heavier for wheel and boost ran at near zero till 60 MPH. More boost more fuel unlocked and boost needs to be kept LOW!

15 hours ago, Honestbest333 said:

AFE Bladerunner GT Series intercooler 3" thick ( denser air burns fuel more completely )

Actually warmer air is best. IAT of 80 to 140℉ is best! Cooler than 60℉ actually reduces MPG.

15 hours ago, Honestbest333 said:

RV 275 Injectors with 7 holes ( Are there better injectors out there for economy ? )

Trick. I'm running 7 x 0.010 150 HP DAP injectors now and there is a twist in mine I'm running 320 bar not stock 310, 305 or 300 like some injectors. You have to figure that into your tuning. For every 10 bar you change is going to advance 1 degree or retard one degree. So 320 bar made me 1 degree retarded. Quadzilla is set up for fairly retarded tune for towing that way boost builds quick and easy. Advanced timing you can run when your empty.