Real World MPG higher than expected

[letswinit]

Received this from a dealer when questioning stated MPG:

"One thing about mileage ratings depends on how good of a driver you are and if you are trying to get the best mileage
how attentive you are. I am an ex race car driver. When I go on test drives I find many customers who think they are going 65 but they
are not steady on the throttle and are going 63, 64, 65, 67. Constant shifts in throttle probably cost you 3-4 mpg. EPA numbers are also
done by honor system and the manufacturers do it with professional drivers. Some manufacturers like Hyundai and some Ford models have
been sued for buyers not getting near the mileage ratings. Also mileage varies according to how fast you drive. On the freeway the biggest
energy user is wind resistance. Aerodynamic drag does not increase linearly with road speed. So if you go 62 mph you may get 4 mpg better
than if you go 72 mpg. I go to Sacramento a lot in my VW GTI because my girlfriend lives there. Going up with a tailwind I get about 3 mpg better
than coming back at the same speed. But if you want good ground clearance in a crossover vehicle the Outback gets incredibly good mileage.
Every inch you lower a car increases your gas mileage about close to 2 mpg due to lower wind resistance. Subaru is not too bad with mileage
ratings. Better than Koreans or most Japanese. Germans are very conservative based on their culture".

[Jcp385]

Mileage ratings are based on tests run according to arbitrary scenario X. Your diving style and conditions will never meet that exact criteria. Hence the difference. One test cannot cover all scenarios.

[Charon]

Unless I am badly mistaken, no official test ever uses maximum power. But real-world drivers, especially of small-engined cars, often do. Imagine the scenario of merging onto a high-speed road (Autobahn, motorway, Interstate) by way of a short uphill entrance ramp. The "official" tests will never get the turbo (on cars so equipped) to spool up. Personally, I think the EPA and its equivalents in other countries simply should stop reporting the figures for fuel economy (or more accurately, fuel consumption).

[Draigflag]

Its the manufactures responsibility to give consumers some sort of idea of what they can expect in terms of fuel consumption, especially as running costs are priority for most people. I've found the dealers themselves are often quite honest, instead of quoting the 90 MPG figures some cars get in the tests, they'll tell you what you should get, and you'd be wise to listen, as most Salesmen have staff cars and ex-demo's that they drive to work every day, so they have experience.

[trollbait]

Personally, I think the EPA and its equivalents in other countries simply should stop reporting the figures for fuel economy (or more accurately, fuel consumption).

Without an official test procedure to follow, the manufacturers will be able to go with their own. Then we will have the situation we have with the numbered traction, wear, and heat rating of tires for fuel economy where the results aren't comparable between companies. Third party testing, like Consumer Reports, are already worse than that with uncontrolled variables between models.

There is also CAFE to consider. It may not be the best method to reducing oil consumption from personal cars, but it does help. The public itself is too short sighted to do so on its own, and the politicians are too cowardly to pass a gas tax to encourage less consumption and pay for infrastructure building and repair.

[Draigflag]

Although grossly exsagerated, as you say, if the test figures are good for anything, then they are good for comparing engines/different cars. Car A might get 20% better fuel consumption than car B in the test, then car A will probably get about 20% better fuel consumption than car B in the real World.

[BDC]

Originally Posted by Draigflag

Although grossly exsagerated, as you say, if the test figures are good for anything, then they are good for comparing engines/different cars. Car A might get 20% better fuel consumption than car B in the test, then car A will probably get about 20% better fuel consumption than car B in the real World.

Absolutely not the case. The EPA tests and regulations are commonly gamed by the OEMs. Ford, Subaru, GM, Chrysler, Hyundai/Kia are all gross offenders and most of them have been fined or lowered their ratings at risk of fine. There are tons of gray areas in the rules that allow powertrains to be rated without testing (such as the C-max debacle), cars not tested with certain options (if an option, such as for example a short gearing option, isn't expected to sell in more than 35% of production cars, it doesn't have to be tested at all).

Hence why we have so many people coming on this board looking for answers why their brand new car doesn't meet estimates.

[trollbait]

They can gamed because the test protocol is known and specific acceleration maps must be followed in order to achieve repeatable and comparable results. The Consumer Reports test can't be gamed because CR doesn't release their test procedure. Their results also can't be compared between models because they were done during different times of the year, outside, and not driven exactly the same way.

There are loop holes that need to be closed with the EPA tests, and the EPA needs more funds to check test more cars. Generally, the more efficient car on the test will be more efficient in the real world. There is just many variables out in the real world.

In order to know what to expect in terms of fuel consumption for an individual car shopper, the person needs to track it with their current car. From that number, they can get a percent comparison to the model's official test number, and use that to estimate what a new model return. Sites like Fuelly, and car reviews can help weed out the ones that may have gamed the test, or are hobbled by it; i.e. diesels on the EPA.

[Jcp385]

Originally Posted by Draigflag

Its the manufactures responsibility to give consumers some sort of idea of what they can expect in terms of fuel consumption, especially as running costs are priority for most people. I've found the dealers themselves are often quite honest, instead of quoting the 90 MPG figures some cars get in the tests, they'll tell you what you should get, and you'd be wise to listen, as most Salesmen have staff cars and ex-demo's that they drive to work every day, so they have experience.

My experience on this side of the pond is completely opposite...salesmen wildly inflate the FE of the car they sell. Figure we'll never check the results.

[trollbait]

Outside the US, at least some of the dealerships are actually company owned and run. Complaints to corporate about dishonest sales people can actually be acted upon.