mpracehemi

I'm relatively new to the cummins world. I bought my truck in March(08) used w/61, miles, it was just traded in the day before. I immediately started changing things. I really didn't have a base line to go from for mpg but I've seen others getting better mileage. Here's a list of what I've done as I have installed in order; S&B air filter- 5" turbo back exh.- afe int. manifold- boost and wastegate fooler (spdiesel from e bay store)- bullydog pmt- bd lift pump- ats trans./conv. (stage 1) w/co-pilot - fuel boss (sp diesel) and gauges.
I've tried 'granny' driving and the best was 11-12 mpg and my way of driving is 9-10 mpg. This is city driving, stop light to stop light. When towing with around 7000lbs. I get around 14mpg. I try using the co-pilot when towing and not towing and it really doesn't make a diff. I don't drive alot so it's a good thing 'cuz of the consumption. Does anyone have an idea as to why the bad mpg?? Any help would be appreciated. THANKS

JCLeary

Some truck suck fuel, some do not. My '07 5.9 mileage blows in comparison to my '03. The last 5 tanks were all within 2 tenths of 12.1 mpg. plus or minus. This *is* with 35" Toyo MT's... No matter what, it's always 3mpg less than the '03.

There are others with '07 5.9's that get great mileage. Don't know what the difference is, but every truck responds to mods differently.

87BRGN

Does sound odd. What year is the truck and what body config? While I agree that two trucks will respond different to the same mods, getting better mileage towing than granny driving... Something doesn't sound right.

By the way Welcome to the forum, lot of well informed members here. If somethings wrong, chances are they can help. If you go to user cp at the top left of forums page you can fill out your sig with all your truck info.

Dave

JCLeary

Where are you going when you're towing? If you're on the open road vs. city streets I can believe it. The truck is much more efficient when the TC is locked.

one54ton

very odd...my 05 gets 17 mpg going 80 on 35s with my smarty tnt on level 3

mpracehemi

Thanks for the feedback and for the welcome of joining this forum. My truck is '05 2500 QC sb 2 whdrive w/stock wheels, gear ratio is 3.73's. When towing, it's usually freeway if it's flowing here in S.Ca.
I traded in a '05 RAM that loved drinking the gas (average 9mpg), but I was over the tow cap. otherwise I would of kept it. I got the diesel for the tow cap. and thought I'd get better mileage with it. I'm about equal when filling up at the pump with the price of fuel between the two.
I tried towing up a hill (with my trailer and car-7000 #'s) that's 3 miles long and about a 8-10% grade. The highest egt was 1240, boost 40 psi, at 50 mph. The trans. temp was 190* and water temp. 200. Weather temp. was around 70* according to my overhead panel. One of my friends told me about this hill and that they used to test turbo's on that hill/grade. I told him the results and he said that was pretty good. Does any one have any comments on this??
Again, thanks for the feedback and welcoming me here. I do like this truck, the torque/power is something else.

mpracehemi

How long does the stock fuel pump last?? Also if the pump fails, can I replace it with say a raptor of a fass pump eliminatiing the stock pump?? I don't want to be stranded anywhere and I want to be prepared. The odometer is showing 65, miles.

rip 112

What are you running that PMt on? Some programmers won't help mileage but rather hurt it, Bullydog can be pretty extreme on your truck.

bluechrome

I wish mine did that! Is that hand Calculatedor was that the overhead lie-o-meter

87BRGN

Those temps under those conditions are great! As far s fuel pumps go... I'm pretty sure your stock pump is in the fuel tank. Those are alot more reliable than the filter mounted ones. (03-04.5 trucks). If your able to pull your fuel pressure down on hard acceleration, I personally would consider upgrade. Theres a few to choose from, all better than stock. AirDog and Fass both have better filters and water seperation. I went with airdog. more fuel than I'll ever use and a lifetime warranty.

Dave

mpracehemi

I was running h.p. on the bulydog, then set it on tow mode and so far it looks like 2 mpg increase. The next step is sitting it on stock mode and see what happens. If I want to go out and play, I'll set the pmt for it. When I set it to stock, I guess the pmt is an expensive gauge set. HAHA.

jwb600

with diesel fuel stupid high I bought a daily driver so my truck can set. if you do the math at 4 fill ups a month for me is $480 so it is easier for me to let the truck set than to drive it plus keep the wear and tear off of it. on the highway my truck shows 18-19 mpg most of the time on the tripmeter but dont know if that is correct, im sure in town is probably what you are getting or worse

rip 112

Well you could come to the brighter side of things....not trying to push Smarty but it would most likely yield you better mileage all around and much more desirable linear throttle response.

mpracehemi

For me, I only drive 2 miles to work. I bought my house after I got this job. I hate commuting. On my overhead fuel mileage is exellant, but doing the math at half tank shows diff. or even 1/8 and 1/4.- miles devided by 17 gals.-4.25 g-8.5g.

chipmonk

believe it or not i get my best mileage with CL, if i keep my foot out of it.