The effects of wind resistance/dragincrease with speed... So the faster you go the worse the mileage will be.
The EPA highway mileage test has an average test speed of only 48 mph, with a top speed of 60mph. If you go faster than this your mileage willalmost surely be less than what the EPA estimates are. http://www.fueleconomy.gov/feg/fe_test_schedules.shtml
The EPA test methods arebeing changed forvehicles produced after 9/1/2007 (the 2008 model year).

 

Well I just picked up a 2007 Ram 1500ST, six cylinder, six speed, with the 3.21 rear end. Tires are set at 35 psi per door jam sticker, oil is Mobil 1 5w-30, last tank was 17.6 mpg, this tank was 19 mpg, same pump, same gas station, mixed use of limited access highway, rural highway and county road, used to haul some building materials and tools and general errands.

Truck is going on a 1500 miles trip this weekend and I will track milage, but so far, pretty happy with the 19 mpg.

Howard

ps: dog thinks this new truck has too high a bed to easily jump into, 68 D100 stepside is in shed getting new rocker panels welded in...

 

Something you need to know is that your engine is not yet broken in, the MDS does not kick in over 65mph (as stated above), and the window sticker number are not based on Interstate speed limits. The highway mpg numbers are done by the EPA which run their tests at 54.5mph, not 70mph. Hope this helps.

 

Is there a way to overide the 65mph limit? Like cut a wire or something?

Its just weird because I will have my 07 Charger going 75+ on cruise and it will be in "fuel saver mode"(says on the dash)

 

Is it stated in the manual the MDS doesn't kick in over 65 MPH? I've set my cruise at 70 and once it's set I see the rpm's drop by about 300 and presume it's the MDS kicking in?

I rode with my grandparents from Minnesota to California when I was 13 thru N. Dakota, Montana, Idaho, Washington, Oregon then down to CA. Whenever my grandpa could he'd draft behind semi's and tried to coast in neutral whenever going down long grades. He got up to 40 MPG in his old Datsun hatchback on some stretches.

The top factors in increasing MPGare driving habits and tire inflation. A little bit more air in the tires might help some but if you put in too much you will get premature wear.

I've found setting the cruise around 65-70 on the freeway resulted in the best mileage for me. The A/C sucks about 2 MPG. Taking trips very early in the morning or late at night during the summer helps with the AC usage and cooler roads make for less wear and tear on the vehicle overall.

 

That damned EPA. It was because of them that I got my V6. Who the hell drives at an average speed of 48mph on a highway.
I drive with the A/C on, it f'ing south florida its 83 degrees, feels like 85 today. I'm in no lab, I have wind against me!!!!!! There are no free flowing highways here, everything has traffic, even rural roads have a f'ing traffic jam. How much money did the US car manufacturers pay you EPA to give those numbers? Bastards!!!!

http://www.fueleconomy.gov/feg/fe_test_schedules.shtml

 

Ususally I get better mileage in the summer vs in the winter. I know in Arizona they add additives to the gas in the summer for pollutants and switch to the "normal" gas during the winter. Also you have to take into consideration the outside temperature which will also make you burn more fuel when its cold out. On average during the summer months my MPG was around 16mpg highest at 20.1mpgand now its down to 14mpg. My truck is an 05' 1500 RC HEMI, and its about what I expected as far as mileage is concerned. Also I have found out thatI generally get bettermileage when I'm drive fast. Going between 70-80mpg is where I get my best mpg. I usually head up to the mountains every month to hunt or fish or something and always take the same road everytime and if I take it nce and easy and go the speed limit (65mph) I get worse mileage than when I take the same trip going 75mph. Granit everything over 80 I can litterally watchthe needle in my fuel gauge drop.

You also have to break it in a little bit more. When I first boughtmy truck it had 23miles on it and my mileage and powerwere bothcrap I maybe got 13mpg tops on a good day and the truck was very sluggishbut after a few thousand miles were put on it jumped to around 14mpg and responded alot betterand jumped again after I put a new exhaust setup on it to between 15-16mpg. And dont simply agree with the overhead unit because 9 out of 10 times its wrong so just do the math yourselfand if you dont know how to figure it out just ask I'm sure lots of people know howto figure it out and can help.

 

{note how the old MPG was calculated}

YOUR WHEELS[/align] Moving toward 'actual' mileage The EPA is updating its fuel-economy ratings to factor in such variables as road characteristics and driver habits.

[/align] By Ralph Vartabedian, LA Times Staff Writer
January 10, 2007 [/align]
If you simply guess how many miles per gallon of fuel your vehicle gets, you might do about as well as the Environmental Protection Agency has over the last couple of decades.

Last month, the EPA announced the first major revision in its fuel economy testing procedures since 1986, aiming to create more realistic mileage comparisons among vehicles.

The EPA acknowledges that fuel economy estimates may drop by as much as 30%, an explicit admission that its prior practices were far off the mark.

A wide range of experts say the new testing regimen should provide more accurate estimates for many drivers, but that they will still fail to capture results that reflect many real-world factors in terms of road, terrain, climate and drivers.

The original method was developed in the 1960s, based on a hypothetical Los Angeles commuter who drove about 11 miles to and from work with an average speed of 21 mph and a maximum speed of 58 mph, according to the 412-page EPA report that implements the new test method. It assumed a driver would encounter no hills and a constant temperature of about 75 degrees, among many other fictions.

The EPA issued its test procedures in the mid-1970s. It updated them last in 1986. The new system will take effect in the 2008 model year.

This system introduces a number of variables, including the more aggressive acceleration and deceleration that drivers increasingly use. It also considers cold start-ups, cold temperatures, the use of air conditioning, some hills and rough road surfaces. A top speed of 80 mph is used as well.

"People's driving behavior has really changed since 1985," said Eric Fedewa, director of global powertrain forecasts at CMS Worldwide, a suburban Detroit consulting firm. "It didn't reflect the way people use their vehicles with a lot of jack-rabbit starts, strong accelerations and high speeds over longer distances."

Under the old system, few drivers have been able to meet or exceed the EPA fuel economy ratings. When the new system is in place, the ratings are supposed to fall closer to the midrange of actual fuel consumption experiences, says EPA spokesman John Millet.

Fuel economy reflects a huge range of variables, and drivers' expectations are often flawed. One belief, for example, is that driving at higher altitudes reduces fuel economy. Not true, says Alan Weverstad, director of regulatory emissions at General Motors.

"Surprisingly, logic doesn't always work," he said. "Since there is less engine vacuum at any altitude, there is less pumping loss with an associated improvement in fuel economy."

Lower atmospheric pressure at higher altitudes is compensated for by engine computers that constantly measure fuel emissions. In some cases, Weverstad said, fuel economy can actually improve at higher altitudes.

But higher altitudes are often accompanied by mountain roads that climb and drop sharply. The extra gas expended going up a hill is seldom recovered coasting downhill, because drivers have to use their brakes to slow down.

The EPA's new model includes moderate hills, but not the mountain driving that exists across the West. It also makes assumptions about how many passengers and how much baggage a vehicle is carrying. Extra passengers or more junk in the trunk consume surprising amounts of fuel.

"For every 100 pounds of stuff you carry, you lose 2% fuel economy," Weverstad said.

Low tire pressure, poor gas quality and many other factors leave consumers disappointed in their vehicle's actual results. And the biggest variable of all is the person in the driver's seat. Paradoxically, drivers complain about the cost of gasoline, but pounce on their accelerators.

Millet said the EPA tests cannot accurately take into account all the variables that occur in actual driving, but that the new system will come much closer.

"It is impossible to design a perfect fuel economy test that will provide accurate, real world fuel economy estimates for every consumer," the EPA report declares.

The tests are performed in laboratories on dynameters, similar to the ones seen at emissions-test stations in California. After getting the results, the EPA then fiddles with them, reducing them for the assumption of hills and rough road surfaces.

The new standards also will contain a significant new truth: The EPA's fuel economy label on new cars will not contain estimates for city and highway mileage, but instead will offer an expected range of fuel economy that most drivers will get.

Once consumers realize new cars are delivering less fuel economy than they previously thought, it may lead to new political pressure to increase government-mandated fuel economy standards, Fedewa said.

"These new tests will make it harder for manufacturers to meet the current standards," he said.

Ann Bordetsky, a policy analyst at the Natural Resources Defense Council, said the new system will provide consumers with a more accurate estimate.

But it is only "a step in the right direction," she said. "There is still a real need for a complete overhaul of the system."

"It might help consumers understand that the fuel economy of their vehicles is not good enough," Bordetsky said.

*

[hr]ralph.vartabedian@latimes.com

 

Want to see 18+ MPG on your Ram Hemi? Drive less than 65 mph so that the MDS kicks in. Use a light foot (which will beat cruise control every time), and ONLY drive with the wind....not against it.

Seriously.....I have made the drive from Wilmington, DE to Myrtle Beach, SC every six weeks over the past two years...in a Nissan Titan, and now in my Ram Hemi. I have gotten widely divergent mpg figures, most of the time due to factors out of my control. I have always driven at 10mph over the posted limit, and have always used cruise control. I am serious with my comment about the wind. While making this 575 mile trip, I have gotten as much as 22 mpg with the Titan, driving north when the wind was out of the south. On the other hand, I have gotten as little as 13 mpg when driving north when the wind was out of the north.

Common sense would tell you that if you are driving 65 mph into a 30 mph headwind, that's equivalent to the same resistance as driving 95 mph on a still day....and no one is going to get great gas mileage at that speed! Winter fuel blends also have an impact. On my first trip from Myrtle Beach to Wilmington with my brand new Ram, again with the cruise set 10 mph over the posted limit, I averaged 17.8 mph with an engine that had less than 1000 miles on it. Two weeks ago, I made the same trip at the same speed, and the best that I could do was 15.9 mph, with 4000 miles on the engine. One of the variables was the switch to winter blended gasoline between the two trips.

Although I like to save pennies just as much as the next guy....in all honesty, when I bought this truck, largely for its performance potential, I had to realize that concerns over gas mileage would need to be "put on the shelf." If I wanted economy, I would have bought something else.

 

keep in mind what you said about engine break in, give it a little time and properly break it in, and you should see a little better gas, also depends on your driving habits