VFIMechanic

so I have a 2500 5 speed, edge ez but comp on the way, exhaust, intake, in tank lift pump, fabtech 5.5 lift with 35 x 12.5 tires. I am under the impression I have 3.55 gears. I just seem to be getting crap for fuel mileage. I usually shift at 15 to 16.5 rpm. Pretty consistent driving patterns. Getting about 14 to 15 average. Any suggestions?

dozer12216

All those accessories have not improved fuel milage, you say? But the cost of accessories would have bought a very big tank of fuel. Which would have taken you quite a bit futher down road. JMHO

nickg

Have you calculated your MPG and adjusted for your tire size? also shifting at 1500 is gonna cause it to lug lots

VFIMechanic

I have not redone my revs per mile yet but it isn't that much of a difference. I think I'm about 4 mph difference. But still.

winger

2002 Ram 2500 with Banks exhaust, module, intake, Michelin 265/75 tires, 3.55 rear end, getting 21 mpg mixed driving.

tx_2500

Your shifting and your Lift are pretty major killers, your tires probably arent helping much. Take into account that a 4:10 with 35" tires ends up converting the rear end to around 3.55. Im not sure what the ratio ends up with a 3.55 and 35's but im sure its getting high. Your trying to turn big tires at a high gearing at a low rpm with your truck way up in the air. Id say your getting what you should in mileage.

collin_bucko

I would say that you should try to shift at a little bit higher rpm (try around 1700-1800), because the lugging of the engine that you are doing, combined with the large lift and tires is probably causing the 15 to 16 mpg.

Hillcountry

Your mileage sounds in the ballpark to me also. Tires and lift will hurt the mileage. With the gearing, shifting that low will lug it...try 2000 and see what happens. 4 MPH difference is also a huge difference. Keep in mind if you have not adjusted your computer for the larger tires, the miles you are using are innacurate so your MPG calculation will be off a little too.