Thread: MEGA cab MPG
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Old 08-25-2012, 06:48 PM
ArtNJr ArtNJr is offline
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Join Date: Jul 2012
Location: Western N.C.
Age: 61
Posts: 240
Gender: Male
Vehicle: 1998.5 Dodge 2500HD 4x4
Trim Level: SLT Laramie
Color: Black
Engine: 1998-1998 359ci (5.9L) Cummins ISB 24-valve Diesel I6 235hp 420lb/ft (manual), 215hp 420lb/ft(auto)
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Originally Posted by Ksmith View Post
I just got back from a family trip to Florida and watched my milage the entire time wo were on the trip.
2007 Hemi Mega Cab, leveling kit, 35-12.50-17 Toyo MT, K&N drop in filter, Flowmaster muffler (no resonator), Diablosport Intune, and Undercover bed cover.
Normal highway driving 55 to 60 sometimes 65 it got 14 mpg, Interstate 70 to 75 sometimes 80 it got 13.5. Thats with the mpg boost programed. It didn't really feel like it lost any power from stock.
Not real sure if thats good or bad but seems ok for a huge truck.
Just for comparison purposes, '98.5 Club Cab 2500HD 4x4, 5.9 diesel, 24-valve, electronically controlled, 4.10 gears & 12.50 x 33 x 16.5 tires -- I've changed back & forth between all-terrain & mud-terrain type, depending on what I'm going to be doing with the truck. I've used it to haul heavy loads & pull trailers to construction sites where there are no roads & I've taken it on three 4000-mile round-trips on the interstate, towing a large & heavy trailer. Bought new in '98, no aftermarket tuning device, but I have made my own free-flow exhaust (no cat, but the truck didn't come with one) & put a K&N air filter in the stock airbox + a little turbo boost trick with the Edge boost elbow, but that's the extent of the modifications.

Overall average fuel mileage = 18 mpg & I should be getting 20 now with the new main injection pump which is vastly superior to the stock one (long story about those).

Worst mileage = 15.6 mpg, in Colorado, pulling a tandem-axle covered trailer loaded up with bikes, tools, etc. that probably weighed somewhere around 6000-7000 lbs.

Best mileage before the new injection pump = 19.3, on the interstate with a tonneau over the bed & just a couple toolboxes inside -- cruise control & A/C on, 65 mph.

Now you know one of the reasons I got a diesel ;-)

Had to add that a friend of mine has a '97 Dodge 3500 Dually 6x6 diesel (12-valve, mechanically controlled) & his has the standard 3.57 gears & highway tires. His average fuel mileage has been about 21 mpg. He owns a vending machine company & carries loaded Pepsi machines, etc. in the back from time to time & sometimes he's got a camper shell on it with not much of a load inside. The bigger tires & lower gear ratio on my truck is what drops the mileage compared to his.
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Last edited by ArtNJr; 08-25-2012 at 07:02 PM.
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