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Car and Driver: These Tests Failed You: Why Is the EPA So Bad at Estimating Hybrid Fuel Economy?

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by cwerdna, May 2, 2013.

  1. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Are you suggesting the EPA gas mileage should change with the weather? That there should be an EPA score for every highway in America? I am unclear what you want.
     
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  2. brucepmiller

    brucepmiller Member

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    I don't want anything Jimbo. I'm just a happy Prius owner!
     
  3. KK6PD

    KK6PD _ . _ . / _ _ . _

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    They did not include nor take into consideration us Hypermilers!!!
     
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  4. walter Lee

    walter Lee Hypermiling Padawan

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    The EPA rating for the Toyota Prius C was done and submitted by Toyota under EPA guidelines.
    The EPA only test and rates a few vehicles independently per year (to keep cost down).
    For vehicles like the Ford C-Max where there is a significant number of complaints the EPA will
    initiate an independent FE test to check the numbers submitted by the manufacturer.
    About 2006, CR/People were complaining that they were not getting th 60 mpg EPA rating
    for the 2004 (2nd gen) Toyota Prius and the EPA change their rating system so the 2007 (2nd gen)
    Toyota Prius was rated at 50 mpg. So Toyota has some experience already under their belt
    with regards to submitting overly optimistic EPA ratings. Hence, Toyota tends to submit
    more modest EPA rating that tend to be closer to the CR results - which is still pretty good.

    LOL. Yeah, Jeremy Clarkson can eat my shorts!
     
  5. cwerdna

    cwerdna Senior Member

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    Close.... original EPA numbers for 04-07 Priuses were 60 city/51 highway, 55 combined. Starting w/model year 08, the EPA rating for all vehicles changed. The new ratings became 48 city/45 highway, 46 combined for Gen 2 Prius. Presumably, for most vehicles (esp. old ones that are no longer sold), they were adjusted by formula and a 5 cycle test wasn't run to derive the new numbers.

    Compare Side-by-Side has the numbers.
     
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  6. kgall

    kgall Active Member

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    I don't get how the Prius C is rated for 46 mpg hwy and the Prius original is rated for 48, when the C is smaller and IIRC a lot lighter.
    Does the differing shape of the rear make THAT much difference to drag?
     
  7. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    It is hard to make a short object aerodynamic.

    The 1.8l is a much newer engine than the 1.5l.

    Cost savings may have come at some loss of technology.
     
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  8. Trollbait

    Trollbait It's a D&D thing

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    +1

    To hit their price mark, Toyota used more off the shelf parts and parts whose R&D have already been paid. That's why the Corolla and Scions still have 4 speed autos.

    The C uses a smaller NiMH pack, and, while it received some efficeincy improvements, the 1.5L is still the same engine as in the gen2 at its heart.

    The weight difference between the C and gen2 doesn't have a large impact on the highway numbers. Aerodynamics have more impact at those speeds. The lighter weight helps with the C surpassing the gen2 on the city test.
     
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