25 MPG Hemi

[scgator]

When not towing, just normal driving, we are getting 22-25.5 MPG with our Dodge Quad Cab Hemi. Most people do not believe it, but we have not modified the truck in any way (other than the correct tires.) Recently, we took a trip to Lima, Ohio (without the TT) getting on the Interstate, we set the cruise for 65 MPH, then after about 2 miles I hit the "reset" 2X on the computer and the fuel management system reset its default to 21.3 ! Many people do not know that you can make your fuel computers recalibrate according to your driving style. Routinely, around town, we average 19-20 MPG doing this......but you HAVE to monitor your MPG and reset as necessary. We get the 25 MPG when cruising at 55 MPH or less on the freeway. If you experience a low mileage reading, such as you would get from merging on an entrance ramp, you MUST reset after you are in traffic, or the computer will default to "the last highest demand for fuel quantity"; in other words, if while merging your fuel mileage dropped to 12.7, then it would default there until you told it different by resetting the computer.

Truck Specs: 2004 Dodge Ram 1500 Quad Cab
Hemi Engine / 5 Speed Automatic
3.55 Rear Gear Ratio / 142,000 miles

[PNWGirl]

Wow, that is pretty awesome and NOT what I would have expected from a truck that size!

Sheila

[HobbyTalk]

The mileage computers in RAMs are notoriously optimistic. Mine consistently showed 1.5 to 2 MPG high.

[RustyJC]

What is your long-term, hand calculated mileage?

Rusty

[scgator]

Originally Posted by HobbyTalk

The mileage computers in RAMs are notoriously optimistic. Mine consistently showed 1.5 to 2 MPG high.

I understand that; and thus do not just rely on its readings. I keep actual records and mileage driven for my calculations and mine is never more than .5 gallons off mathematically. One of the areas that causes the erroneous readings is using a shorter tire than is recommended for the truck; some people like the "sportier looking" tires which are of a different height to width ratio. I, too did not get the MPG I am getting until I changed to a REAL truck tire, made for trucks. It is both, more narrow and taller and now my readings work out real close, computer versus actual math.

I know everyone has pros and cons on this type of issue, however, we make a LOT of trips during the year without our TT and I monitor this real closely, not because I am cheap, but because I like being efficient. MANY factors effect overall mileage on any vehicle; I am simply stating what we have and and what works for us is a combination of mechanical and driving habits. These are our REAL world numbers that we enjoy frequently. In fact my wife and I went to lunch (Chinese Buffet) and about 12 miles of the trip was expressway. We set the cruise on about 53 MPH (speed limit was 55 mph) because of a light rain, and the computer read 25.6 MPG. EVEN if this was off by say 2 MPG, it is still GREAT mileage for anybodies 6000# truck

[scgator]

Originally Posted by RustyJC

What is your long-term, hand calculated mileage?

Rusty

I keep a calculator and notebook in the truck at all times, so that we can calculate trip expenses, and do not "fudge" on the numbers; these are real numbers; our last trip to Lima, Ohio from our home in South Carolina put slightly over 1400 miles on our truck, and our total gas expense round trip was $221.00 Our good mileage numbers are not just the result of "working the computer", they are a combination of things such as good tune up, correct tires and inflation, driving habits, etc. On the Intersates, I always set my cruise 2 MPH below the posted speed limit, that allows me to stay consistent in the traffic; oncoming traffic KNOWS what I am doing and can plan ahead to pass me as they approach, and does not cause others any problems. The only people that it causes problems for is those that usually want to run 10-15 MPH over the posted limit; and then it wouldn't really matter, they are upset at anyone slower than them, irregardless of the speed they are driving............the 2 MPH difference allows my engine RPM to not exceed 1500 RPM and that is where my best mileage is. Yours maybe different if your rear gear ratio is different.

[JIMNLIN]

Use your pencil and divide gallons used into miles driven over several tanks of fuel and then report back with the pencil numbers for a actual average MPG and not just a single best tank.

I can reset my overhead 'puter on my '03 2500 Dodge/Cummins NV5600 3.73 axle while driving also and it tells me I'm getting 43 mpgs.

[scgator]

Originally Posted by JIMNLIN

Use your pencil and divide gallons used into miles driven over several tanks of fuel and then report back with the pencil numbers for a actual average MPG and not just a single best tank.

I can reset my overhead 'puter on my '03 2500 Dodge/Cummins NV5600 3.73 axle while driving also and it tells me I'm getting 43 mpgs.

I have been doing this for over year thank you and it is consistent week in and week out......tank after tank; I am sorry if you doubt this, but I KNOW the real numbers, and I know it is accurate. My reasoning for this post was simply to help people learn to get better mileage, not to cause an ISSUE.

[scgator]

Originally Posted by JIMNLIN

Use your pencil and divide gallons used into miles driven over several tanks of fuel and then report back with the pencil numbers for a actual average MPG and not just a single best tank.

I can reset my overhead 'puter on my '03 2500 Dodge/Cummins NV5600 3.73 axle while driving also and it tells me I'm getting 43 mpgs.

Yes, mine will show ridiculous mileage to, but if you will pay attention it is while the truck is on a sometimes "slight" incline in the roadway and then it will level out as the roadway height and angle change as you drive. You, sir are "splitting hairs" trying to find something wrong, and it is not condusive with "the spirit of the forums"

WHAT your computer is telling you is that in order to maintain your speed, the amount of fuel being delivered to the injector yields a certain amount or measure of fuel, AND, if during that process, the computer finds itself in a "lesser load" parameter (such as a slight decline in the roadway), it will report a higher mileage calculation; the signal pattern for the computer software checks cycle at over 200 times per second, thus it is very easy to post an erroneous figure momentarily.

[scgator]

Originally Posted by PNWGirl

Wow, that is pretty awesome and NOT what I would have expected from a truck that size!

Sheila

When I first got the truck, I did not realize it was possible to do this until I did some Chrysler Corporation "research" on some older service manuals and tech bulletins; starting in late '03, they started using software that allowed you to change the parameters away from factory defaults........this allows you to tailor the truck to your individual driving habits. I know I have doubters and skeptics, but I have ENJOYED this for over a year now, and still going strong.

[scgator]

Originally Posted by scgator

When I first got the truck, I did not realize it was possible to do this until I did some Chrysler Corporation "research" on some older service manuals and tech bulletins; starting in late '03, they started using software that allowed you to change the parameters away from factory defaults........this allows you to tailor the truck to your individual driving habits. I know I have doubters and skeptics, but I have ENJOYED this for over a year now, and still going strong.

I have a brother-in-law that has an '05 with the six cylinder, who complains all the time that he cannot get near the mileage I get; but, he will also tell that when he is on the Interstate...he never drives under 80 mph unless his radar detector suspects something. IT IS AS MUCH DRIVING HABITS AS ANYTHING; ALL FACETS WORK TOGETHER....

[scgator]

In the mid 80's General Motors used something similar to this on the Cadillac Fleetwoods; they called it a 4/6/8 system. As you were cruising, the less demand on the engine for speed, the computer would first cancel out two cylinders and then as load requirements decreased it canceled out two more, so that in effect, you were cruising down the Interstate like a four cylinder instead of a 472 cubic inch V-8. And they had very good success with it as it laid the foundation for modern fuel management systems that today give 30+ MPG routinely.

[PNWGirl]

Originally Posted by PNWGirl

Wow, that is pretty awesome and NOT what I would have expected from a truck that size!
Sheila

Originally Posted by scgator

When I first got the truck, I did not realize it was possible to do this until I did some Chrysler Corporation "research" on some older service manuals and tech bulletins; starting in late '03, they started using software that allowed you to change the parameters away from factory defaults........this allows you to tailor the truck to your individual driving habits. I know I have doubters and skeptics, but I have ENJOYED this for over a year now, and still going strong.

Yeah, I have been a bit surprised at the tone of some of the responses.

One of my vehicles is a 1998 Dodge Grand Caravan. A few days before Christmas last year, my neighbor slammed into it and I rented a 2011 Grand Caravan, for the week it was in the shop (never let your neighbor hit your car before Christmas....).

I was so shocked, when calculating the mileage, to find that it got poorer mileage (significantly worse) than my '98 van.

I was happy to read of someone who has a vehicle who did better as, you would think, there would be significant increases in mileage between the old cars/trucks to ones 13 years newer.

Sheila

[rbursek]

Actually the 4-6-8 was a flop!!! GM/Cadilac recalled the engines and set them to run on all 8 cylinders because they where not shifting back and forth as they were designed to.
Bob