Is this good?

[adarby84]

I recently bought a 2002 4wd cclb F-350 SRW. I have put a 5" turbo back exhaust with 4" dp, a 6637 filter on, and 285/75-16's that I run at 60 psi . I get 16.5-16.8 mpg hand calculated every tank is this good or is there something that I could improve on? I am saving up for a PHP chip and hope this will help some. I have just never had a diesel so I am not sure.

Thanks

[SuperCrutyPS]

Is that in town or highway, running empty (Not loaded or towing)?? If highway, what speed ya running?

[adarby84]

Sorry about that. That is mainly 2 lane hwy with some city mixed in. 60-70 most of the time unloaded. I drive about 100 miles a day with about 20-25 of that being city driving.

[SuperCrutyPS]

That's pretty good for highway running.

Is 285/75R16 stock size? If not, you may be getting a bit better if you calculate the difference in tire size from stock.

Tire size calculator I use:
Tire size calculator - Put in the stock size and the new size. It will tell you the differences including a percentage. Multiply miles driven by that percentage and then divide by gallons. You might see a bit better MPG.
Example: Say difference is 3%. Say you drove 300 miles and put in 18 gallons.
Under the old way, 300 / 18 = 16.66 mpg
New way 300* .03 = 9 = 309 / 18 = 17.16 mpg
Not a big difference, but more accurate.

[adarby84]

No stock is 265 I think. I will have to check that out next fill up.

[adarby84]

Ok checked it tonight. Including my 7.3% for tire size difference I got 16.67 mpg. I forgot to mention that I have 3.73's

[SuperCrutyPS]

7.3% difference??? Maybe a typo??

When I looked at the tire calculator above, I saw a 3.7% difference.

[jesilvas]

Doesn't sound terrible.
If you keep the RPMs at about 2k and below it'll help.

['01SilverBullet]

Yea, that sounds about right. I've calculated mine out to 17.0, on the same sized tires, going around 60 for the most part on a two lane. Mine's an extended cab, short box, so it's just a smidge lighter.

[adarby84]

ok so 3.7% is actually correct did the tire think with the wrong aspect ratio. So with that percentage factor I had 236.4 miles and 14.771 gallons so right at 16.0mpgs. Is there anything else that I can look at doing or should I just write it off as this is a big truck and that what its gonna do?