Mazda provides pre-production vehicles to teh EPA. Mazda does not conduct it's own mileage tests for the purpose of advertising. AFAIK Mazda cannot tweak or specially prepare a car for the EPA because the production cars they sell new is 'certified' by the EPA as to it's configuration etc...

If you have a concern about poor mileage on your Rx8 I suggest reviewing this rather dated EPA document.

http://www.epa.gov/otaq/cert/dearmfr/gasmel.pdf

The methods have not changed since 1985 and there is a petition (see below) to consider overhauling current calculation methods to be more realistic.

My own limited observations are that EPA estimates sometimes tend to be conservatively low - in many cases as many or more poeple reports BETTER than EPA estimates as compared to worse. However in the case of the Rx8 - clearly there is antecdotal evidence to suggest they are quite generously high estimates (to Mazda's benefit?). Many are experiencing observed mileage far below the EPA estimates. Are others observing mileage equally ABOVE those estimates? I don't think so.

While I'm sure Mazda isn't rushing to seek a modification to those EPA estimates... If you wish to file a complaint w/ the EPA regarding innaccurate observed mileage (beyond the couple of MPGs they say are acceptable) - try contacting them at:

http://www.epa.gov/otaq/mpg.htm#regs
http://www.epa.gov/epahome/comments.htm
http://www.epa.gov/oigearth/ombudsman-hotline.htm

At say ~$2/gal and a nominal 10,000 miles a year - over 5 years, a 5 mpg discrepency adds up to ~$1,350.00. An efficient cars, sports car or otherwise - arguably has added benefits beyond cost such as the environment and maybe some day mitigating the need for political/military entanglements in certain unstable areas of the world.

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From: http://yosemite.epa.gov/opa/admpress...b?OpenDocument this may also be of interest from a year ago:

(1) EPA Seeks Comments on Gas Mileage Testing Procedures
John Millett 202-564-7842 / millett.john@epa.gov

In response to a petition submitted to EPA by the environmental organization Bluewater Network, EPA is asking for comments on its testing procedures for determining gas mileage estimates via a notice in the Federal Register. Each year, EPA's city and highway gas mileage estimates are displayed on new vehicles and appear in the annual Fuel Economy Guide. The purpose of the notice is to obtain feedback on the topics raised by the petitioner who contends that EPA's current testing procedures, which were established in 1985, do not reflect factors that may affect the fuel efficiency of today's vehicles, such as increased highway speeds and urban traffic congestion. This action will have no effect on the fuel economy standards (CAFÉ) now in place and administered by the National Highway Traffic and Safety Administration. A copy of the notice and the petition can be found at:http://www.epa.gov/otaq/mpg.htm#regs or in EPA Air Docket OAR-2003-0214.

 

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information has been posted before but thanks for the reminder