Gas Mileage ???

[HighOnHendrix]

Reported mileage is usually overdone because EPA tests in perfect conditions.

Those types of tests are generally done by professional drivers in perfectly optimal weather and driving conditions.

Not only are the conditions "optimal", they are not even on real roads! They perform the EPA tests on a dynamometer!

http://www.edmunds.com/advice/fueleconomy/articles/105503/article.html

New vehicles are tested by the manufacturer according to guidelines outlined by the EPA. The EPA in turn reviews the results and confirms 10 percent of the test results with additional testing in the National Vehicle and Fuel Emissions Laboratory (NVFEL), in Ann Arbor, Michigan. The cars are tested by putting the drive wheels on a "dynamometer," a machine that allows it to simulate driving conditions while remaining stationary.

A tremendously good Car & Driver article on the subject:

http://editorial.autos.msn.com/article.aspx?cp-documentid=1089144&icid=autos_money3

While the public mistakenly presumes that this federal agency is hard at work conducting complicated tests on every new model of truck, van, car, and SUV, in reality, just 18 of the EPA's 17,000 employees work in the automobile-testing department in Ann Arbor, Michigan, examining 200 to 250 vehicles a year, or roughly 15 percent of new models. As to that other 85 percent, the EPA takes automakers at their word — without any testing — accepting submitted results as accurate.

From the same article:

Vehicles are tested on dynamometers, or dynos, which are like giant treadmills for cars. The vehicle is held stationary while its wheels spin the dyno's large rollers. ...After a vehicle is strapped down on a dyno, the staff punches in coefficients that allow the dyno rolls to simulate real-world factors, such as wind and road friction.

One of the EPA's six drivers is behind the wheel of the test car. With an average of 20 years' experience, they have extremely fine-tuned throttle and brake-control skills. They "drive" by following a precise red line of speed versus time that's displayed on a monitor hanging just in front of the windshield. Using the gas pedal and the brakes, the driver attempts to match the red line with the car's wheel speed, which is shown in white.

Every last detail of an EPA fuel-economy test has specific rules — there’s even a set volume of air that a fan must blow under the car’s raised hood. "Driving" the test by matching the red line is tricky and takes a sensitive foot.

[fullnelson9999]

According to this site, you should be averaging 33mpg on the highway and 23 in the city.

Sounds like you aren't getting as great of a bargain as you might of thought.

http://www.automotive.com/2006/12/pontiac/g6/specifications/index.html

well there have been many other sites saying it should be less

[DeanCollins]

maybe the engine and tranny need to break in.

exactly, don't expect top mileage till after break in. My father bought a new BMW 320i in the '80s. He drove it so slowly (trying to get the best mileage because has cheap) that the engine hadn't loosened up at 7k miles. He complained that he was only getting 20 mpg. I borrowed the car for a weekend and revved the crap out of it and gave it back to him. A week later he called me all happy saying he was getting 28 mpg (epa rated it 30 hyw).

[Capt. Kaos]

I do drive a tad fast (75mph in a 70 speed limit) but still.

I'm no expert but I do believe that you may have answered your own question right ^^ there ^^

[SkinnedAussie]

^^^^^^^^^^^^^

I do drive a tad fast (75mph in a 70 speed limit) but still.

That also confirms my query in regards to being a professional driver.

[Tarpon75]

Just bought a 2010 Kia Soul. The advertised mileage was 24 city/30 hwy. I just went on a trip today out of town and got about 21 mpg (all highway driving). I seriously just bought the car a few weeks ago.

Would there be a reason for this? Can car companies lie about the gas mileage? Pretty pissed.

In my opinion something is wrong somewhere.Regardless of driving conditions I believe you should be doing way better than you are doing for fuel economy.If you don't get better mileage than that it defeats the purpose of buying a small vehicle..There are cars with V-8 engines that get better mileage than you are getting.

[Capt. Kaos]

In my opinion something is wrong somewhere.Regardless of driving conditions I believe you should be doing way better than you are doing for fuel economy.If you don't get better mileage than that it defeats the purpose of buying a small vehicle..There are cars with V-8 engines that get better mileage than you are getting.

Did you see his post where he states he drives 75 mph on a regular basis?!?

There isnt a V-8 out there that would get better gas mileage under the same driving conditions that this car is put under.

Oh and 1 thing that I just caught re-reading the OP:

The car companies do not have anything to do with the EPA listed MPG information. That all comes from the government.

edit: Found this website with a calculator for showing the average difference with different driving speeds. It may not be 100% correct but even if only marginal it makes a HUGE statement.

[twa]

Did you see his post where he states he drives 75 mph on a regular basis?!?

So?...I have a Hyundai suv:silly: with a V-6 that will get almost thirty mpg cruising at 75+(best cruising seems to be between 80-90,but there is that little matter of laws;))

If his numbers don't improve with breakin there is a problem imo.

[DeanCollins]

Did you see his post where he states he drives 75 mph on a regular basis?!?

There isnt a V-8 out there that would get better gas mileage under the same driving conditions that this car is put under.

edit: Found this website with a calculator for showing the average difference with different driving speeds. It may not be 100% correct but even if only marginal it makes a HUGE statement.

Capt, the "website" says that the "average car" will have these results. There a lot of cars with 5 and 6 speed automatic and manual transmissions that have two overdrive gears and the torque to pull those ratios. These cars might get better gas mileage above 55 mph. But a little rice burner (like the op's Kia) is only going to rev higher and burn more gas.

[Capt. Kaos]

Capt, the "website" says that the "average car" will have these results. There a lot of cars with 5 and 6 speed automatic and manual transmissions that have two overdrive gears and the torque to pull those ratios. These cars might get better gas mileage above 55 mph. But a little rice burner (like the op's Kia) is only going to rev higher and burn more gas.

That was posted to give an idea of what speed will do to gas mileage not as an end all be all informational site. There are a ton of factors that can play in to gas mileage but I think in this particular case that speed is the undermining cause of the MPG issue.

Not to mention that the car is definetly not "broke in" as of yet and the OP is driving it at 75 mph, that can't be good for the engine.

That last part is pure speculation as I have never owned a new car.

[Skinsfan1311]

At 75mph, you'll never get the gas mileage advertised.

At this time of year, I believe that many companies put ethanol in their gas. My gear-head friends told me that ethanol decreases gas mileage.

[DeanCollins]

At 75mph, you'll never get the gas mileage advertised.

At this time of year, I believe that many companies put ethanol in their gas. My gear-head friends told me that ethanol decreases gas mileage.

there's no doubt about that. I'd put it at 10% less by my observations. FL mandated ethanol be added to all gas. The stupid thing about it is that if you add 10% ethanol, for the purpose of reducing oil consumption (foreign oil), and it reduces fuel economy by 10%, you've accomplished nothing by raising the price and lessen the availability of corn. In the mean time ethanol damages your fuel system and engine components. :doh:

[aszumilo]

^^ yea but in my 05 magnum v8, it has a MDS engine (multi displacement system), it cuts to 4 cylinders at highway cruzing speeds. Once the car is going at a steady speed, its gets better gas milage.. i only notice better milage on long trips though and not in the city areas. Do the MDS's uses more milage when it changes from 8 cylinders to 4?

When you say it cuts to 4 cyl at cruising speed, it has already gained the momentum from using it in 8 cyl mode. Therefore, it does not have to work very hard to keep the momentum going.

The way the engine works is quite a bit different than the same size vehicle with different displacement engines and the work load that is required. The question is not whether the mds in 4cyl mode uses more or less gas, but rather, did the 4cyl mode do all the work to get you to cruising speed? Technically, it would be possible to keep it in 4cyl mode all the way to cruising speed, if you take off slow from a stop and driving it slowly to keep it in 4cyl mode. Think about how much longer that would take to get there using that method than utilizing all 8 cylinders.

From researching MDS, I see that many people are stating that their mileage is worse than a non-mds engine. In my opinion, mds is not really worth it and only adds more crap to go wrong in the motor. I really did not see much improvement in mileage estimates between the mds and non-mds Hemi engines, actually on Dodge's site the estimated mileage for a 2009 Ram 1500 5.7L Hemi MDS truck no better than what my 04 non-mds motor is listed as.

2009 - 14/20

2004 - 14/18

[I_Bleed_B&G]

I sometimes get 11mpg in the city lol and about 17 highway in my car. Its a freaking gas guzzler

[Springfield]

2004 Ram 1500 5.7L Hemi 14/18

2004 Ram 1500 4.7L V-8 12/15

2004 Ram 1500 3.7L V-6 15/21

First, I'll compare the 3.7L to the 4.7L.

The 3.7L has .62 L/cyl (liters per cylinder). The 4.7L has .59 L/cyl. This means the the cylinders in the 3.7L have a larger volume than the cylinders of the 4.7L. Larger volume means more fuel is needed in order to complete combustion.

All that said, the 3.7L does have significantly better fuel economy. 3 MPG at city and 5 MPG at highway is a lot better... about two cylinders less better.

Now as to the 5.7L engine, the Hemi. The answer to why the 5.7L Hemi engine gets better fuel economy than the 4.7L engine despite the larger amount of displacement is quite simple. Efficiency.

The major draw of the Hemi engine is it's efficiency. The efficiency of the Hemi engine is what allows it to produce such power and it also what allows it to get better fuel economy. The shape of the combustion chamber (basically the cylinder head and piston crown) allow for a much better atomization of the air/fuel mixture. Thus, more power and better fuel economy... modest improvements considering there is one more liter of total displacement.

Closing statement, the V-6 still gets better fuel economy... because it has less cylinders in the engine and weighs less overall.

[Springfield]

At this time of year, I believe that many companies put ethanol in their gas. My gear-head friends told me that ethanol decreases gas mileage.

All gasoline in Northern VA has 10% ethanol at all times of the year. It's mandated. There should be a sticker on the gas pump you fill your car with that says the gas may contain up to 10% ethanol.

And yes, ethanol does decrease fuel economy. It's only a marginal amount though.