Improve my diesel's fuel economy?

Site Notices

[ARCHIVED THREAD] - Improve my diesel's fuel economy?

Posted: 8/8/2007 2:21:02 PM EDT

I recently bought a 7.3L Ford Superduty, not because I pull a 20' gooseneck loaded with iron, but because I do some moderate towing, and I wanted the better fuel economy diesels tend to boast. I'd previously owned a Superduty with a 5.4L V8, and that ran at about 16 mpg average unloaded, and 14 mpg towing. My newer 7.3L has been getting 16 to 18 mpg, so as far as I'm concerned I'm coming out ahead. I've got a bigger truck (club cab as opposed to ext cab, both 3/4 tons), more power, but better fuel economy.

Now, I'm looking for a way to boost it further. My goal would be 20 mpg, I think that's attainable, I know lots of Cummins drivers get that without doing anything.

Are there any chips, boards, programmers, tweaks, etc that are for fuel economy? Everything I've found while doing research has claimed increases in HP or torque, but I don't care about increasing my available power. I've got more than enough to pull what I need to pull, and I would even take a decrease in net power if it boosted my economy, provided the ratio was there. Say, -10% power to +5% mpg.

Posted: 8/8/2007 2:36:05 PM EDT

[#1]

Juice

www.cyclonediesel.com/edge.htm

Posted: 8/8/2007 2:40:05 PM EDT

[#2]

I'd try an electric radiator fan.

Posted: 8/8/2007 3:26:19 PM EDT

[#3]

A lot of the diesel guys lie.

I think they do it because they feel compelled to say anything to save face, after being duped into spending $50,000 on a new pickup by some unbathed coke-head car salesman in a $100 suit, who told them that they'd be able to get 25 mpg.

Then, two weeks after the purchase, the new owner takes his mosquito-killer back to the dealership. The coke-head and his comission check are long gone. So he goes to the service department, thinking that there must be some warrantable defect of the vehicle. The service consultant points to a row of brand new oil-burners still sitting on the lot, and as politely as possible, asks the new owner to show him where it is on the monroney sticker that it says that he's supposed to be getting 25 mpg (it doesn't- the manufacturers make NO fuel mileage claims on these vehicles).

Get two or three of these diesel owners together, and they begin to play this sort of one-upsmanship game, each claiming that he's getting better fuel mileage than the next. Pretty soon, we've departed from reality as we know it.

I'm sure that there are others that have gotten better (actual) fuel mileage than me, but the best fuel mileage that I've ever personally experienced was a consistent 20 mpg from my old crusty non-turbo 6.2-powered 3/4 ton 4x4 Suburban. What really pleased me about it is that the truck had a 6" lift kit, 4.10 gears, 35" mud tires, and due to some additional off-road equipment, scaled at 7250 pounds. With a 40-gallon fuel tank, it was capable of just about 800 miles on a single tank of fuel. But I kid you not, it was by far, the slowest motorized vehicle that I've ever operated. It was frightening at night, going through the Northern California hills at night on the I-5, towing a motorcycle trailer to Laguna Seca. I'd put my hazard lights on, because even with my foot to the floor, it would only pull about 45 mph up some of those hills.

Posted: 8/8/2007 4:59:05 PM EDT

[#4]

Diesels do very well considering how much power they put out. If we were really interested in economy we'd use a 3.0L twin turbo like BMW does. 37.7 MPG in the EU combined cycle with power numbers that are damn close to a late 90's 7.3.

If you wanted a big block you could have diesel performance, but you'd only get 8 MPG.

Posted: 8/8/2007 9:03:19 PM EDT

[#5]

Quoted:
A lot of the diesel guys lie.

I think they do it because they feel compelled to say anything to save face, after being duped into spending $50,000 on a new pickup by some unbathed coke-head car salesman in a $100 suit, who told them that they'd be able to get 25 mpg.

<snip>

+1 to that.

And don't forget it doesn't matter if they are towing thier buddy's broken down semi with 80,000lbs home behind thier boat, with their family in the truck, uphill into the wind at 80mph passing all of the POS <insert brand of truck besides theirs> .

I call it learning to speak diesel. The computer in my 2007 LMM Duramax says 16.3 mpg right now for everyday driving. I think it's probably right. When I hook my 11,000 lb toyhauler up to it it drops down to around 10-11. Pretty darn good if you ask me.

Posted: 8/8/2007 9:14:33 PM EDT

[#6]

Plus you're moving a big assed truck around,the Freightliner daycab bobtail will get,at the most,around 10-11 mpg,which drops down to around 7 mpg or so with the trailer loaded.

Posted: 8/9/2007 2:27:32 AM EDT

[#7]

i'm pullin about 20 out of my 01 cummins.

16-18 is good mileage. the only thing you can do to try and get better mileage is make sure everything is running 100%, such as clean fuel filter, injectors, so on and so forth. or regear your truck to run lower RPM's at 75. so long as you stay in the powerband your mileage will increase.

Posted: 8/9/2007 2:31:22 AM EDT

[#8]

Quoted:

Quoted:
A lot of the diesel guys lie.

I think they do it because they feel compelled to say anything to save face, after being duped into spending $50,000 on a new pickup by some unbathed coke-head car salesman in a $100 suit, who told them that they'd be able to get 25 mpg.

<snip>

+1 to that.

And don't forget it doesn't matter if they are towing thier buddy's broken down semi with 80,000lbs home behind thier boat, with their family in the truck, uphill into the wind at 80mph passing all of the POS <insert brand of truck besides theirs> .

I call it learning to speak diesel. The computer in my 2007 LMM Duramax says 16.3 mpg right now for everyday driving. I think it's probably right. When I hook my 11,000 lb toyhauler up to it it drops down to around 10-11. Pretty darn good if you ask me.

this is true, but on the other hand, i have had many experiences where i have towed XXXX miles and acheived the same, or slightly lower mileage as unloaded. I have also had experiences where i was unloaded, driving into a heavy cross/head wind, and have only gotten 11 mpg out of my stroke.

your mileage may vary.

Posted: 8/9/2007 5:30:02 AM EDT

[#9]

I get 14 MPG with my M1010 CUCV military 4X4 ambulance and that's with 4.56:1 gears, TH 400, 6.2L and probably weighs around 7,000 lbs. I have a lot of fun driving it and don't mind going 50-55 MPH on the Interstate as any faster than that I can practically watch the fuel gauge drop before my eyes. I'd like to get a M1009 CUCV Blazer due to its higher fuel economy but the wife says I'm on thin ice the way it is with what I have right now.

Posted: 8/9/2007 12:14:58 PM EDT

[#10]

Quoted:
i'm pullin about 20 out of my 01 cummins.

16-18 is good mileage. the only thing you can do to try and get better mileage is make sure everything is running 100%, such as clean fuel filter, injectors, so on and so forth. or regear your truck to run lower RPM's at 75. so long as you stay in the powerband your mileage will increase.

The number one set-up issue that I come across in 3/4 ton-and-up trucks, is that the operators tend to run the tires half-flat. Read the door sticker. If it says to put 80 pounds of air in your rear tires, put 80 pounds of air in your rear tires. You'd be startled to see the differences in fuel mileage that tire pressure can make.

Posted: 8/9/2007 12:21:04 PM EDT

[#11]

I run proper tire pressure. I buy fuel that is known to of good quality. I use a fuel/cetane treatment. I use a larger 4" exhaust for lower EGT's. I use a tuner for tow/economy tune. I can average 16-18 city driving, but my right foot seldom lets me.

There are good tuners/boxes and even custom tuning software(EFI LIVE) thta are great and customizable for your application.

My ride is a CC, 4x4, GMC LBZ/Allison.

Posted: 8/9/2007 12:21:51 PM EDT

[#12]

Two other issues that I come across are:

Idiot tire store employees installing load range "C" tires (like for a half-ton), on vehicles that require a minimum of a load range "E" tire. That's pretty much all 3/4 ton and 1-ton trucks.

The other one is whatever obssesive-compulsive disorder it is that causes the vehicle operator to purchase and install every single external body accessory that J.C. Whitney sells for their particular vehicle. It really affects the amount of air that you have to push when you've got all sorts of dortons and farbs attached to the outside of your vehicle with adhesive, pop-rivets, sheetmetal screws, and velcro.

Posted: 8/9/2007 12:27:17 PM EDT

[#13]

Quoted:
I run proper tire pressure. I buy fuel that is known to of good quality. I use a fuel/cetane treatment. I use a larger 4" exhaust for lower EGT's. I use a tuner for tow/economy tune. I can average 16-18 city driving, but my right foot seldom lets me.

There are good tuners/boxes and even custom tuning software(EFI LIVE) thta are great and customizable for your application.

My ride is a CC, 4x4, GMC LBZ/Allison.

I really like the Isuzu medium-duty diesel that GM is currently using in their light-duty trucks. Isuzu has a long and successful history of building high-quality Japanese diesels that are easy to live with.

Posted: 8/9/2007 1:35:07 PM EDT

[#14]

Quoted:

The other one is whatever obssesive-compulsive disorder it is that causes the vehicle operator to purchase and install every single external body accessory that J.C. Whitney sells for their particular vehicle. It really affects the amount of air that you have to push when you've got all sorts of dortons and farbs attached to the outside of your vehicle with adhesive, pop-rivets, sheetmetal screws, and velcro.

This annoys me. "Oh look my truck is custom because it has decals and shiny rock guards."

I'm sorry, that's about as custom as a "custom" Dell or "custom" 1911 from ~~Armscor~~ Taurus.

Posted: 8/12/2007 7:49:46 PM EDT

[#15]

'84 m1009 cucv (59k) about 20; '86 gmc jimmy diesel (with 240K) about 22; '97 f350 crew cab longbed 4x4 (139k), maybe 18.

Posted: 8/12/2007 9:22:26 PM EDT

[#16]

It's all about towing, in my humble little bit of experience.

My experience with diesel trucks is limited so keep that in mind. I am also not a big diesel fan, or truck fan either as a matter of fact, I think I am allergic to diesel smoke, the stuff drives me nuts, I can't breath I sneeze and cough, all from being in traffic near a diesel vehicle. It is safe to say I really don't have a dog in the fight.

My experience is with Ford vans. A few years ago I was doing contract cell site work, and for nearly a year I was testing and replacing batteries in equipment on cell sites. I would pick the batteries up in a Ryder rental van (two or three pallets at a time), install the new batteries and lug the old ones back to the warehouse. If I was switching out vans about every two weeks for maint or whatever, and if I was in Jacksonville I would get a diesel, in Augusta a gas van.

The gas van, when empty, was the best, it was faster and got better gas mileage. It was when the vans were full of batteries that the diesel shined brightly. When the gas van had batteries on it, it was scary merging onto the interstate, slow and gutless doesn't really explain it adequately, the MPG also dropped way down. The diesel however, didn't seem any slower with a full load, and the MPG didn't drop much either. With the gas van I was getting about 7-19 MPG empty, about 8 MPG loaded. With the diesel I was getting about 15-17 empty and 14-15 loaded. At one point the company fuel card wasn't working, it was the middle of the night and I was low on cash. I had a full load of batteries, and an empty tank. I got to doing some math, and figured I had enough money to get me to the warehouse in ATL, and then back home to Augusta. If it had been a gas van I would have had enough to get to ATL before I started pushing. The next morning the fuel cards were working again, but I still refused to take a gas van again.

I can't really tell you how to get better mileage, but can attest to the fact that when loaded heavily the diesel will be more economical than a gas engine. However if I wasn't going to be hauling some very heavy loads I probably wouldn't consider a diesel. The old 96 F250 4x4, extended cad I drove for years (company vehicle) at the phone company was gas and very reliably got 16-17 MPG, another tech had a truck identical to mine except it was a diesel, and he got 14MPG reliably. These last numbers are not boasts or guess work, I was on charge of keeping up with all of the company vehicles assigned to our site, and one part of that responsibility was maintaining a spreadsheet that tracked fuel used and mileage driven in all of the vehicles. By the way the best MPG came from a Windstar that all the new techs had to drive when they first hired on, they all hated it, until they had been given an LWB F250 for a while, then they would bitch and want the Windstar back.

Posted: 8/13/2007 9:58:13 AM EDT

[#17]

Next time you're on the freeway, take a look around at all the $50,000 diesel pickups rolling down the highway empty, with no trailer, occupied by a lone driver. If they were really interested in fuel mileage, they'd be driving a Honda Civic.

Posted: 8/13/2007 2:40:23 PM EDT

[#18]

Quoted:

Quoted:
i'm pullin about 20 out of my 01 cummins.

16-18 is good mileage. the only thing you can do to try and get better mileage is make sure everything is running 100%, such as clean fuel filter, injectors, so on and so forth. or regear your truck to run lower RPM's at 75. so long as you stay in the powerband your mileage will increase.

The number one set-up issue that I come across in 3/4 ton-and-up trucks, is that the operators tend to run the tires half-flat. Read the door sticker. If it says to put 80 pounds of air in your rear tires, put 80 pounds of air in your rear tires. You'd be startled to see the differences in fuel mileage that tire pressure can make.

Define 'proper tire pressure'. The sticker on the door is for max load capacity NOT necessarily the same pressure you want when running empty. Granted you MPG will be better with overinflated tires but you're paying for the MPG increase with decreased tire life, reduced traction, worse ride.

Brian

Posted: 8/13/2007 3:15:30 PM EDT

[#19]

Quoted:
Next time you're on the freeway, take a look around at all the $50,000 diesel pickups rolling down the highway empty, with no trailer, occupied by a lone driver. If they were really interested in fuel mileage, they'd be driving a Honda Civic.

One nice thing is that they're now finally making some smaller diesels for those of us who like to commute in them. That Grand Cherokee with the 3.0 and the new GM 4.5 diesels look very interesting. The bad part about the 4.5 Duramax is that it was designed solely by GM engineers.

I can imagine you share the belief that Isuzu should have played a nice role in the design effort. It'll first be offered in 1/2 ton pickups and H2 Hummers, from what I've read. I can imagine it will next show up in Suburbans and Tahoes. It does sound promising from the specs though. 310 HP and 520 lb-ft definitely sounds more than adequate, and practical, for the commuter/occasional toy hauler-home depot picker-upper.

Posted: 8/13/2007 6:23:35 PM EDT

[#20]

Pffft, you are a bunch of sissy boys. 25-30 in the city, 35 on the higway in a car older than you are

(80 mercedes Diesel)

Posted: 8/13/2007 6:36:07 PM EDT

[#21]

Quoted:

The bad part about the 4.5 Duramax is that it was designed solely by GM engineers.

you do realize GM has produced some of the most efficient motors in the past 15 years, right? if the new diesel is as good as the LS series of motors, the others of the big 3 are going to be left scratchig their heads, AGAIN.

Posted: 8/13/2007 8:27:18 PM EDT

[#22]

Using PRI-D with every tank will make your filters last longer before they plug and get slightly better mileage. Even this new low sulphur deisel the manufacturers are allegedly concerned about because they don't want a repeat of the original lower sulphur diesel lubricity issues isn't that good.

All-synthetic fill will get you 1MPG or so and reduce temperatures and vibration.

Put the tailgate up. Driving with it down reduces your mileage according to every manufacturer.

Inflate your tires properly.

Posted: 8/13/2007 8:36:12 PM EDT

[#23]

Quoted:

Quoted:

The bad part about the 4.5 Duramax is that it was designed solely by GM engineers.

you do realize GM has produced some of the most efficient motors in the past 15 years, right? if the new diesel is as good as the LS series of motors, the others of the big 3 are going to be left scratchig their heads, AGAIN.

The last diesel that GM designed on their own didn't work out so well. Am I saying this one will be a flop? No, but it sure wouldn't have hurt them to let the whole Duramax conglomeration design this one. The 6.2 (and later the 6.5 built on that platform) was a good enough design, but that was Detroit Diesel. This one is wholly GM designed and there are a few things I noticed that will make building one up for drag racing and such not a very easy or practical task (integrated head/exhaust manifold). Banks may just come up with some good aftermarket and the engine stock sounds like it will be really great, but some of the design may not lend itself well to the aftermarket and/or home R&R jobs.

Time will tell.

Posted: 8/14/2007 7:30:05 AM EDT

[#24]

A small amount of biodiesel is said to improve mileage.

Posted: 8/14/2007 9:51:57 AM EDT

[#25]

Quoted:
snip

Why do tire manufactures generate tables that list weight on the wheel with the corresponding recommended pressure?

Bottom line: "Proper tire pressure" is dependent upon the load the tire is subjected to. Running 50 psi in the 315/75R16 rear tires on my '00 Dodge 2500 when unloaded is over inflated for the conditions. Running 50 psi when I'm hooked up to my 36ft 5th wheel is just about perfect.

Brian

Posted: 8/14/2007 11:18:48 AM EDT

[#26]

Quoted:

One nice thing is that they're now finally making some smaller diesels for those of us who like to commute in them. That Grand Cherokee with the 3.0 and the new GM 4.5 diesels look very interesting. The bad part about the 4.5 Duramax

Ford and Dodge are also coming out with smaller diesels in their 1/2-ton trucks. I am very thankful for this, if I could only get my hands on one of those 4cyl diesels in the S10s over seas...

Posted: 8/15/2007 3:44:23 PM EDT

[#27]

I use the DP-Tuner chip is my 02 7.3l PSD. I got 20MPG on the highway unloaded. Haven't checked city driving yet, but it's closer to 15-16.

Before that, I was getting 15-16 on the highway and 11-13 around town.

This is all with the 80HP Econo tune. I don't have anything else installed besides a Quadzilla commander monitor to check EGT/Boost/etc temps/PSI.

Chip was ~$240, well worth the money.

Posted: 8/15/2007 4:00:20 PM EDT

[#28]

Quoted:
Ford and Dodge are also coming out with smaller diesels in their 1/2-ton trucks. I am very thankful for this, if I could only get my hands on one of those 4cyl diesels in the S10s over seas...

Definitely. I would *love* to get some kind of diesel in my '05 Jeep Unlimited, especially if it was something without the '07 or 2010 emissions requirements.

[ARCHIVED THREAD] - Improve my diesel's fuel economy?

General » Cars, Bikes, and Trailers

Warning

Confirm Action

About AR15.COM

Stay Connected

Newsletter

Contact Us