Home Forums Gear Hunting Trucks and Four-Wheel Drives Diesel Newbie Needs Mods Advice

I am learning to really like my new diesel (2007 Dodge 6.7). I am, however, disappointed in the gas mileage. This last tank, with mostly highway miles, only got 16.5 MPG. Are there any modifications worth doing that will actually help gain MPG? It is my daily driver so gaining some fuel efficiency would be nice. I am driving much more sane with it than I ever did with a gasser.

Since this is all new to me, specific recommendations would be appreciated.

Head on over to www.cumminsforum.com and ask the same thing there.

1st thing you should do though is add on a 2 micron fuel filter

http://www.offroadpowerproducts.com...-2012-dodge-cummins-67l-mk21012-blk.aspx


Won't gain you any mileage, but it will help protect those spendy injectors.

Might want to consider some extra oil filtration as well, both it and the fuel filtration are recommended by cummins.

Its hard for me to grasp cummins saying they recommend better filtration systems then they built into their design from the start?

+1000.

I have redundant 2-micron filters pre-OEM, and a secondary bypass oil filter.

One thing to check out is a centrifuge oil filtration system. Supposed to clean oil much better than a bypass (better particle counts) and no filters to replace (just clean the housing periodically). If I didn't already own a bypass, I'd probably get the centrifuge.

Oh, and I stay away from non-stock air intake systems, like the K&N, etc. At least on the Duramax, guys make big power using factory AC Delco pleated paper filters, and I'll take the extra filtration any day and twice on Sundays, thank you.

Bottom line: particle contamination, whether in fuel, oil, or air, are not good for components. Filters are your friends.

You take care of that Cummins, and you can drive it a long, long time.

Jim:

My understanding is that the Bosch common rail fuel injection system was designed for much higher-quality diesel than is commonly available in the USA. Apparently diesel quality is better in Europe.

And so, we filter.

So

There is a huge difference in diesel in South Africa, it has anti foaming added. I can fill my cruisers to the edge of the pipe as easy as I can with petrol.

The percentage of Diesel cars and trucks may be approaching 40% in Africa, and probably 90% in the rural areas where there are 100 miles between fuel stops. Farmers, ranchers, and all rural folks will only own diesel because they have their own 1000 gallon tanks filled by truck as needed and then use it for all vehicles.

I know several with ATV and side by sides that also run diesel. America has been decades behind the diesel curve when compared to europe and At least in Southern Africa if not all of Africa. The Diesel automobiles will hands down beat the prius for fuel economy every day getting 60 plus MPG under any conditions and they are only 1/2 the price! The Diesel Jag, and BMW M5 with the diesel are about equal to the economy of the Prius and 100X the performance and luxury. Without having that huge toxic battery to figure out how to replace or dispose of!

Rick summed it up basically, but here's this

http://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/LT36172.pdf


Also don't cheap out on cheap filters, spend the extra 4-8 bucks and get quality ones (fuel, oil, & air).

Perhaps filling with diesel instead of gas would be a good start. (grin)

Welcome to the diesel club, Robert.

Sounds like somebody messed with the fuel plate. Does it smoke?

Common rail injection on an ' 07. No fuel plate.

How fast do you drive on the highway? Most diesels become pretty thirsty over 70 mph.

That's fascinating Jim. Odviously a very easy to understand example as what our stupid clean air/global warming regulations are costing us. E

remfak;
I'll preface my answer with the understanding that we've never run much US diesel through our current rigs, so I can't speak to the specifics of the fuel quality.

We've had a '90 Jetta TDI for 17 years and our current pickup is an '03 Ram with the 305HP/555ft/lb 5.9 L Cummins.

As well, a nephew is a HD mechanic who is trained/certified for Cummins engines among others has been a valued source of information for us regarding our '03.

One thing we do notice up here is that we do get noticeably better fuel mileage once the stations stop using winter diesel. We don't see a lot of bio-diesel here in BC thus far either, so I'm not sure if a higher bio-fuel content might have a positive or negative effect on economy.

In our experience, I'd certainly second or third the recommendation to not go to an oiled gauze air filtration system. We gave K&N filters a try on a 4.6 Ford gas and our Jetta and were not impressed at all. None of the mechanics I've talked to since recommend them, especially so for turbo diesel engines.

A friend in Alberta had a 6.7 that got significantly poorer mileage than his '04 with the 5.9. He replaced the entire cold air intake with a K&N system and reported no change at all in either power or economy.

He then chipped it - Bully Dog I believe - and that did help the mileage.

The central Alberta dealer he dealt with - and btw one sees a pile of diesel pickups in oil country - indicated to him that the '07.5 with the newer engine series weren't expected to get as good fuel economy as the older series....Isn't "progress" wonderful sometimes?

The folks who suggested this sight -http://www.cumminsforum.com/ - were spot on in my experience. Think of it as a Campfire for Cummins enthusiasts and there are a lot of us out here.

I did install a silicone rubber "Cool Hose" on the intake to the turbo - but using the stock air filter. I picked it up from these folks and received very good service from them.

http://www.dieselpowerproducts.com/...-finally-got-them-67l-dodge-cummins.aspx

I'd say we picked up about 1 mile per Imperial gallon by installing the Cool Hose and can certainly hear the turbo spooling up a bit quicker. I should note that on our '03 it did increase the amount of turbo whine we can hear in the cab. That doesn't bug me, but might not be welcome for others.

My nephew insisted we run either a Fleet Guard or Dodge oil filter. There was one other one that escapes my memory as well, but according to him all filters are definitely not made equally.

We run an additive in our fuel to help lubricate the pressure pump. We've had no or low sulfur diesel here in Canada for a long time now, so an additive can't hurt I figure. We've been using mostly this stuff and as far as we're aware it's been doing what its supposed to.

http://www.powerservice.com/dk/

I'll note that in my research it didn't fare quite as well as some other additives like Amsoil, but because the Diesel Kleen is so easy to find up here it gets the nod.

Based upon a bunch of reading and asking, we use Shell Rotella T in the Cummins, but use Castrol Super Diesel RX in the Jetta - which by the way has 411,000km on it and runs like a proverbial clock. Anyway, I do believe it pays to use a quality oil suited for turbo diesel applications.

I've not added auxiliary filtering yet in either the fuel or the oil, but clean fuel and clean oil can never be considered a bad thing with a turbo diesel.

Sorry for taking so long to spit this all out. Hopefully some of it was some use to you. Good luck with your pickup.

Regards,
Dwayne

I go between 70 and 75 mph, slower than I used to go with my Toyota. I keep it below 2k RPM's as well.

That could be part of the problem but not all of it.. Seems like over 70 MPH fuel consumption really goes up on my truck. My truck is a 2006 Chevy with the Duramax, but I think I can still get around 19 MPG on level ground at 70 MPH. Best I ever got was 22.8 MPG running at speeds from 55 to 65. As long as I can get between 17 MPG and 20 MPG with a 7,500 pound 4 wheel drive truck I am happy.

Just completed a 1900 mile trip to NM trout fishing and i keep it between 2000 and 2100 RPM We just averaged 19.4 MPG (hand calculated) in our 2005 Dodge CTD 4x4.

I run a AFE intake system, and smarty on level1.

ML

The big difference is the 6.7 and the new emissions systems. You have got more power than the 5.9s mentioned above, but you pay for it in mileage. You can take off some of the emissions components and get a little better mileage and even more power. Try www.dieseltruckresource.com as a good source of information. They have forums on modifying 6.7s.

Yes new Diesels have new emissions crap on them and they suck. But new engines are putting out way better millage than before. GEARS AND DRIVE RATIOS are the biggest factor next to the loose nut behind the wheel. I have a friend that runs a 2005 6.7 cummins in a 3500 Dually and can average about 21 on the highway.

He also has an open exhaust and a mild program adjustment but all emissions crap is in place.

Probably a 5.9L in 2005. It had way fewer emissions systems. The 6.7L Dodge came out in 2007.

Good catch sir I got my engine years all mixed up. The truck is a 2004 Not 2005 of course it is a 5.9L. If I remember right around 2003 the 5.9 got a Common Rail Injection system.