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Why Is The Prius Such A Drag?

Discussion in 'Gen 2 Prius Main Forum' started by Smooth Operator, Aug 11, 2006.

  1. Smooth Operator

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    I have always had pride in the low coefficient of drag (Cd) of the Prius.

    Then I took a look on Wikipedia at the Cd of various cars. According to that source, there is a surprising array of vehicles that outperform the Prius on this criterion.

    0.26 - Toyota Prius, 2004
    0.26 - Vauxhall Calibra, 1989
    0.25 - Dymaxion Car, 1933
    0.25 - Honda Insight, 1999
    0.24 - Audi A2 1.2 TDI, 2001
    0.212 - Tatra T77 a, 1935
    0.20 - Loremo Concept, 2006
    0.20 - Opel Eco Speedster Concept, 2003
    0.195 - General Motors EV1, 1996
    0.19 - Alfa Romeo BAT Concept, 1953
    0.19 - Dodge Intrepid ESX Concept , 1995
    0.19 - Mercedes-Benz "Bionic Car" Concept, 2005 [2] (based on the boxfish)
    0.16 - Daihatsu UFEIII Concept, 2005
    0.16 - General Motors Precept Concept, 2000
    0.14 - Fiat Turbina Concept, 1954
    0.137 - Ford Probe V prototype, 1985

    (http://en.wikipedia.org/wiki/Coefficient_of_drag#Typical_values_and_examples)

    So with all of the work by Toyota on Cd, it appears that we still have room for improvement. Maybe there will be a "new look" Prius. And maybe it will look like this:

    http://upload.wikimedia.org/wikipedia/comm...Tatra_T_77a.jpg
     
  2. azzieo

    azzieo Junior Member

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    It seems like the Insight and the A2 are the only mass production cars that are a lil' better... Everything else is concept or old.. or both.
     
  3. hyo silver

    hyo silver Awaaaaay

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    A perfectionist would say there's always room for improvement. As good as the Prius is in many ways, it could be better. Note most of the cars listed are design concepts, not production cars. Buckminster Fuller's 1933 Dymaxion is my favourite. It's amazing how far we *haven't* progressed in 70 years.
     
  4. rfred

    rfred New Member

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  5. Scott_R

    Scott_R Member

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    <div class='quotetop'>QUOTE(Smooth Operator @ Aug 11 2006, 07:21 PM) [snapback]301786[/snapback]</div>
    According to here and here the A2's Cd is 0.25
     
  6. Godiva

    Godiva AmeriKan Citizen

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    Seems to me I see a lot of 'concept' and 'prototype' on that list.

    Mind reducing it to cars that exist that you can acutally buy? (That eliminates the EV1 right off.)
     
  7. daniel

    daniel Cat Lovers Against the Bomb

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    The Prius could have had a lower CD if it had been a lower car. Do you want to give up a foot of head room to reduce the drag a bit? Or do you want to sit with your butt 6 inches off the pavement and have to struggle to get out of the car? The point of the Prius is that it achieves phenominal mileage and cleanliness without sacrificing comfort or performance!
     
  8. Tideland Prius

    Tideland Prius Moderator of the North
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    You forgot the LS430 at 0.25 with air suspension

    What about the Saturn GM EV1?
     
  9. jimmyrose

    jimmyrose Member

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    <div class='quotetop'>QUOTE(Smooth Operator @ Aug 11 2006, 07:21 PM) [snapback]301786[/snapback]</div>
    I'm not sure Wikipedia is an accurate or reliable enough source to base such claims on...
     
  10. Autosmiler

    Autosmiler New Member

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    <div class='quotetop'>QUOTE(Smooth Operator @ Aug 11 2006, 06:21 PM) [snapback]301786[/snapback]</div>
    I don't see how that car in the last link would have a better Cd than the Prius. Or is that not what you were implying? Maybe I just don't understand aerodynamics...
     
  11. Godiva

    Godiva AmeriKan Citizen

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    <div class='quotetop'>QUOTE(Tideland Prius @ Aug 11 2006, 08:31 PM) [snapback]301851[/snapback]</div>
    It's halfway down the list as General Motors EV1.

    And it is no longer in production and was never available for purchase.

    Neither were any prototype or concept cars so I'd like those taken off the list.

    Likewise, I think it's unlikely I would be able to find a car from the 1930s to purchase, so scratch those too.

    There are some I just don't recognize at all. Are these some sort of boutique auto requiring the winning of several lotteries to purchase? (Like the Tesla?)

    Let's get practical and only list cars it's possible to buy. Even though the Insight is no longer being sold, you can still pick one up on the secondary market so I'd say that stays.

    Now, perhaps the original poster can revise the list for practical purposes?
     
  12. Tideland Prius

    Tideland Prius Moderator of the North
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    sorry, I didn't see the EV1 on that list. My mistake.
     
  13. NuShrike

    NuShrike Active Member

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    <div class='quotetop'>QUOTE(ZenCruiser @ Aug 11 2006, 06:43 PM) [snapback]301860[/snapback]</div>
    and Nature's recent study concluded that the Wikipedia is about as accurate as the Encyclopedia Britannica Online, including rebuttals to Britannica's complaints about the study.

    IMO, there are some that dislike/distrust Web 2.0's Wikipedia and I think they have control issues, dislike web forums and working collaboratively and loosely coupled with people, and unsubstantiatedly think only single-source paid-for corporate works guarantee shinier quality and accuracy versus actual history (Windows vs FreeBSD/Linux, etc).
     
  14. Cheap!

    Cheap! New Member

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    <div class='quotetop'>QUOTE(daniel @ Aug 11 2006, 08:27 PM) [snapback]301848[/snapback]</div>
    Now you guys are talking my language... That is why I want to find an “Adjustable Hydraulic Suspension" for the Prius. Just think 6 inches off the ground at highway speeds and 6 inches above where it is now when you are parked. Easy in and out of the car, and lower drag when it really counts, highway speeds. Add rear skirts and ground effects in front of and between the wheels and we might be looking at 65 mpg at highway speeds. On long trips between this and the 12 gallon tank, people would be just begging for a potty break.
     
  15. Frank Hudon

    Frank Hudon Senior Member

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    I actually never found the EV1 attractive and if that's what it takes to get to .195 I don't want it. .26 is good enough.
    Edit: well you can't have one now anyhow. So that's redundent.
     
  16. hampdenwireless

    hampdenwireless Active Member

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    <div class='quotetop'>QUOTE(Godiva @ Aug 11 2006, 08:54 PM) [snapback]301831[/snapback]</div>
    GM may have only leased them and then crushed most of them but it was a car available to the public and should not be talked about if it was totally unavailable and not in public hands.

    The Prius is quite slippery as it is, .26 is not a bad # at all. Its a more usefull car then any of the other production cars.
     
  17. Smooth Operator

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    <div class='quotetop'>QUOTE(ZenCruiser @ Aug 11 2006, 06:43 PM) [snapback]301860[/snapback]</div>
    I'm not sure either, which is why I put the "according to Wikipedia...".


    <div class='quotetop'>QUOTE(Autosmiler @ Aug 11 2006, 07:36 PM) [snapback]301901[/snapback]</div>
    The Cd of the Tatra T77 is 0.212, noticably lower than the .26 of the Prius.


    <div class='quotetop'>QUOTE(Godiva @ Aug 11 2006, 07:45 PM) [snapback]301907[/snapback]</div>
    I don't think the point is, "What is available?" rather, "What is possible?". It Toyota had started the Prius with the premise of "What is available?" they wouldn't have made any advances in the first place. I think it is remarkable that there are cars on the list that are over 70 years old that have lower Cd than the Prius.
     
  18. priusenvy

    priusenvy Senior Member

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    This thread is idiotic.

    It's trivially simple to design a car with a lower Cd than the Prius. Any upper division student in a decent AE or ME program could do it. Hell, I could probably do it and my undergrad degree is in EE. Throw in the constraints of:

    1) passenger and luggage space requirements
    2) packaging (size)*
    3) cost
    4) acceptable styling
    5) compliance with govt safety regulations
    6) etc.

    and suddenly it's not so easy to achieve those low Cd numbers. Is this not obvious to you?

    *Cd is independent of frontal area, but a shape that is longer compared to its width and height has a lower Cd. I could build a fiberglass tail for my Prius that would lower the Cd but it would not be practical for many reasons.
     
  19. tripp

    tripp Which it's a 'ybrid, ain't it?

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    <div class='quotetop'>QUOTE(priusenvy @ Aug 12 2006, 02:35 AM) [snapback]302031[/snapback]</div>
    What he said. At least 2 of these cars are two seaters (EV1 and Insight). I'm not familiar with any of the other ones (except the Probe... heh heh, probe, which isn't a "practical" car). 0.26 cd is fine. It's an effective design that gets good gas mileage. Bullocks to the rest, they're not significant.
     
  20. Godiva

    Godiva AmeriKan Citizen

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    <div class='quotetop'>QUOTE(hampdenwireless @ Aug 12 2006, 12:16 AM) [snapback]301986[/snapback]</div>
    I'm talking about what is available now. What I can go out and buy and drive. Otherwise, what is the point? Why include a car from the 30s. It's not like I can go out and buy one. Same with the concept cars. You're comparing apples and lugnuts. I'll accept the Insight as an orange because you can probably still buy them used on the secondary market. You can't do that with an EV1. So go ahead and compare apples and oranges, but leave the lugnuts out of it.


    <div class='quotetop'>QUOTE(Smooth Operator @ Aug 12 2006, 01:25 AM) [snapback]302008[/snapback]</div>
    Yes, it is. And there's one from the 20s that is built sorta like the Scion that supposedly has a real low Cd.

    But again....I can't buy it.

    Could they lower the Cd of the Prius even more? Yes, as has been stated previously by lowering it, cutting the headroom and you'd have to get down into the car like a racecar.

    You know what? Let them leave that design for a newly designed hybrid sports car. I gave up a car like that. A Saturn SC2 coup. I had to sit down into that car. I have back problems now. One of the reasons I bought the Prius is that the car seats like a chair, not like a race car.

    Why are so many concept cars on that list? Why didn't they become production cars? The Prius and the Insight were produced and sold and are owned and being driven on the road. They are attainable. A concept car is not. A car from the 30s is not. They are interesting curiosities. But not very practical.