I just bought a 2007 Cummins (5.9L) and it has a 6 inch lift with 37's on it. I was just curious as to what kind of mpg this thing should be getting. Obviously it wont be as good as it was with factory tires but Im only getting between 10 and 11 mpg. Was wondering if this was about right or if I might be losing fuel somewhere.

I have a 2001 Cummins with 35's and Im getting anywhere from 14-16 mpg depending on driving so was just comparing the two.

Another question maybe someone can help me with. Not all to familiar with this lift or if that is even the problem. But whenever I come across some rough spots on the road the left (left side only) starts wheel hopping. Like violently. I have to slow down so it will quit doing it. Right side no problem. ???????????

Thanks

 

sounds like your second gen with 35's has 4.10 gears.

and your 07 likely has 3.73 gears. 4.10 would probably net better economy with 37's because of the big size difference.

also make sure you are calculating off of either a corrected speedometer, or a GPS odometer. your hand calculated MPG will be way off with those huge tires...

and you can't trust the overhead lie-o-meter either.

my overhead says I get 19mpg more like 15.5

 

Thank you sir.

 

Yes the overhead is way off. its saying like 19. aint no way. so basically if i take it in and get recalibrated my problem should be solved correct???????? hopefully....

then my hand calculations should be correct i hope........

 

yeah, my speedometer is like 3-8mph off (depending on speed) and it makes a good 40 mile or so difference on the end mileage.

so I use my in dash nav to do my trip miles since it goes off of GPS rather than the speedometer.

I prefer my speedometer to be off anyway keeps the miles lower on the truck! I have my adrenaline's pulse monitor set to display corrected vehicle speed as one of its 4 gauges it displays so I know how fast I'm actually going to take the guess work out of it.


if you know anyone near you that has a smarty programmer, they can correct your speedometer for you for free.

 

thanks. i appreciate it

 

hey just throwing this in to the mix. Im currently driving a 2011 1500 with a hemi in it and looking at trading up to a 2500. Just wondering if anyone could shed some light on what the milage is typically like. As in real road numbers not what the manufacture posts...
Also if anyone can give me a best estimate what the fuel milage would be like while towing about 6500lbs?
Ill probably tow this about 2-3000km per year.
As is im looking about about 9mpg while towing it (i think im doing to the math from 25L/100km sorry guys im from canada)
As for regular driving think im posting about 14 MPG in the winter and 15/16 MPG in the summer thats mostly city driving.
Looking for some compairatives with a diesel (2010 or newer if possible.)

Thanks

 

the 6.7L's wont get any better economy unless you get DPF/EGR deletes.

after the deletes they can get up to 22mpg or so empty and like 12-15 towing (with stock tires)

with emissions crap still in place they will get like 15mpg hwy and 10mpg towing...


pre 07 trucks will all get around 18-23mpg empty (depending on gear ratio) and around 12-15mpg towing (depending on load weight and gear ratio)

 

Alright next question in regards to that last response. Bare with me seeing as my 01 didn't have all the emsissions stuff. What is all this DPF/EGR delete stuff and does my 07 5.9 have it? I know there was a change when they went to the 6.7 but not sure if mine still has it. And if it does have it how do I go about getting rid of it?

 

no, the 5.9L did not have the emissions crap on it.. has a cat, but I think that was about it...

The 6.7L was the start of the DPF/EGR cooler crap.