Engine/Transmission (1998.5 - 2002) need help with milage

[JNeiman]

ok, my 2001 2500 4x4 with an auto and 4. 10s now has 57000 miles on it and is earning a very good 21mpg. Only mods are the EZ and K&N. Now the other truck, the 2000 3500 4x4 has 65000 miles and i am only getting about 16mpg. Granted the truck has a slide in dump bed with a headache rack that sticks up about 6 inches above the back of the cab, but it has slots and shouldn't grab that much air. This truck has a 6 speed, 3. 55s, 4" exhaust, K&N, and a Powermax 3 on setting 5 for highway. I am basing these milage numbers on long highway journeys averaging 70-75mph. What gives for the lower milage on the 3500? I am also considering 275 injectors. What gain can I expect? What should I do for the present to get the milage up? I am driving to Michigan Tuesday (12 hours all highway) and would like to see closer to 20mpg or better. Thanks, JOE

 

[jlhartak]

Well, the 3500 should weigh considerably more than the 2500, you have 6 tires on the ground with rolling resistance vs 4 plus the duals stick out and catch air.



What did the trucks get before the EZ and Powermax? The 2500 is a little above avg. and the 3500 a little below. A friend of mine gets 16-17 on his 98. 5 24v 3500 at about 9000lbs. I get 19-20 on my 99 2500 QCSB at 6800lbs. both trks are stock 5spd and 3. 54; I do have a 4" exhaust.



Have you taken into account any changes/errors in tire size, speedo, etc. in figuring mileage?

 

[GMocanu]

Need help?

If you need help then what do I need? I've got a 01. 5 2500 QC SB 4x4 6spd with 4. 10 and the best that I've ever gotten was 18. 5. I've got a BHAF and 275's. My last tank was 15. 8. My EZ will be here on Tuesday so I'm interested what my mileage will be when I get it installed. That is, after I get done playing with it.