Page 1 of 3 123 LastLast
Results 1 to 15 of 38

Thread: Why does the Toyota Prius get much better MPG then the Lexus CT 200h?

  1. #1
    Join Date
    Sep 2009
    Location
    Los Angeles
    Posts
    9

    Why does the Toyota Prius get much better MPG then the Lexus CT 200h?

    So the Toyota Prius and Lexus CT 200h both have the same drivetrain.

    The drag coefficient on the Prius is 0.25
    The drag coefficient on the CT 200h is 0.29

    The weight of the Prius is 3042 lbs.
    The weight of the CT 200h is 3130 lbs.

    Yet Gas Mileage Varies Big Time

    The Prius gets 51 in the city and 48 on the highway
    The CT 200h gets 43 in the city and 40 on the highway

    Can anyone please explain the huge difference in Fuel Economy?
    Last edited by henk4; 05-15-2011 at 10:04 PM.

  2. #2
    Join Date
    Oct 2006
    Posts
    10,156
    I think a difference of .04 in the drag coeffecient is semi-large. They also may not have the same frontal area.

  3. #3
    Join Date
    Dec 2003
    Location
    nr Edinburgh, Whisky-soaked Scotland
    Posts
    27,778
    yes, the relevance of 0.04 ( sounds a small number ) is that it means the CT has 16% MORE DRAG.

    Check out the higway figs especially --- 20% better , close enough as kitdy says for small change in frontal area to account for the rest
    "A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell'

  4. #4
    Join Date
    Apr 2003
    Posts
    5,457
    But at EPA cycle speed, which I think is like 65mph or something like that, we are not talking huge number here....

    It might be the car is geared differently, or just that the car had different tuning in terms of how it behaves at normal drive cycle....

    BTW I saw one of these the other day, the car is a lot smaller than I thought....
    University of Toronto Formula SAE Alumni 2003-2007
    Formula Student Championship 2003, 2005, 2006
    www.fsae.utoronto.ca

  5. #5
    Join Date
    Oct 2007
    Location
    Modena
    Posts
    9,826
    Not to mention different tires, suspensions, engine ECU maps, aerodynamics (which is much more complex than just Cx), gearbox management and so on and so forth.

    The two tires/wheels available on the Prius make a 5% difference in fuel consumption (the larger wheels are worse in this regards).

    The difference in mileage between the Insight and the CR-Z is 15%.

    No wonder these two are different as well.
    KFL Racing Enterprises - Kicking your ass since 2008

    *cough* http://theitalianjunkyard.blogspot.com/ *cough*

  6. #6
    Join Date
    Dec 2003
    Location
    nr Edinburgh, Whisky-soaked Scotland
    Posts
    27,778
    Drag starts from low speeds.

    Just dip the clutch and see how it slows down.
    Then try the same with a wind and see how it slows down quicker.

    There's a lot of drag at 65mph
    "A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell'

  7. #7
    Join Date
    Oct 2007
    Location
    Modena
    Posts
    9,826
    Tires friction is quite relevant as well, maybe more than drag at low speeds (65 mph is not that slow).
    KFL Racing Enterprises - Kicking your ass since 2008

    *cough* http://theitalianjunkyard.blogspot.com/ *cough*

  8. #8
    Join Date
    Jun 2005
    Location
    East Coast of the United States
    Posts
    11,805
    100 lbs would do a bit of difference too. Think about it, you have another person with you in the car.

    In America's case, you'd have about 1/3 of an extra person in the car.

  9. #9
    Join Date
    Oct 2006
    Posts
    10,156
    I drove a CT. It was pretty boring and crappy, but it was the first hybrid I had ever driven so I was quite thrilled.

  10. #10
    Join Date
    Apr 2003
    Posts
    5,457
    Quote Originally Posted by Matra et Alpine View Post
    Drag starts from low speeds.

    Just dip the clutch and see how it slows down.
    Then try the same with a wind and see how it slows down quicker.

    There's a lot of drag at 65mph
    But it will be a bigger contributor as the speed increases, and the city cycle driving, which is done largely below 55 mph, drag will not be the main contributor, at least I don't think to the tune of 8mpg.

    CT was designed to be more of a hybrid to the tune of CR-Z, as in maybe less boring(doubtful) and with some sacrifice of pure mileage performance in order to look more exciting, with the big wheels and tires. I'd guess the extra inertia from that probably hurt its MPG performance too....
    University of Toronto Formula SAE Alumni 2003-2007
    Formula Student Championship 2003, 2005, 2006
    www.fsae.utoronto.ca

  11. #11
    Join Date
    Dec 2003
    Location
    nr Edinburgh, Whisky-soaked Scotland
    Posts
    27,778
    Get a low friction car and a low wind and see the difference in each direction.

    MAN the kind of things teachers got us to do as kids to learn the reality of a physics lesson. WHere are those kind of lessons now

    but yeah, lots of other variables involved !!!!
    "A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell'

  12. #12
    Join Date
    Sep 2009
    Location
    Los Angeles
    Posts
    9
    Great responses thanks....Both vehicles have the same CVT trans and they both wear low rolling resistance tires.

    Just seems like quite a difference.
    Last edited by henk4; 05-15-2011 at 10:02 PM.

  13. #13
    Join Date
    Apr 2003
    Posts
    5,457
    Quote Originally Posted by Matra et Alpine View Post
    Get a low friction car and a low wind and see the difference in each direction.

    MAN the kind of things teachers got us to do as kids to learn the reality of a physics lesson. WHere are those kind of lessons now

    but yeah, lots of other variables involved !!!!
    Mulsanne's Corner Race Car Aerodynamics Database: 2001 Mazda RX-7 and RX-7 R2

    RX-7 arguably less aerodynamic than a Prius, produces ~300 lb of drag at 150mph. Drag quadruple with speed, at 75 mph you are looking at 70-80 lb of drag. Do you get 8 MPG less with a kid sitting in your car?

    I wouldn't be surprised though if the CoD is not the only measure that the CT is less efficient than the Prius, its not the sole contributor to actual drag force a car is carrying.

    Plus big wheels and tires you are accelerating that every time you stop and go in the city cycle....
    University of Toronto Formula SAE Alumni 2003-2007
    Formula Student Championship 2003, 2005, 2006
    www.fsae.utoronto.ca

  14. #14
    Join Date
    Feb 2005
    Location
    Barcelona
    Posts
    33,448
    Quote Originally Posted by RacingManiac View Post
    I wouldn't be surprised though if the CoD is not the only measure that the CT is less efficient than the Prius, its not the sole contributor to actual drag force a car is carrying.

    Plus big wheels and tires you are accelerating that every time you stop and go in the city cycle....
    I think that's probably the answer. Despite the similar drivetrain they are in the end very different vehicles, therefore the difference in offficial figures.
    Lack of charisma can be fatal.
    Visca Catalunya!

  15. #15
    Join Date
    May 2007
    Posts
    205
    Being that I know nothing about drag coefficients other than the fact that lower is better, I was really surprised to actually see the different numbers put into a percentage. 16% is a fairly sizeable improvement.

    Quick question for the American members on here, as we're talking about low fuel consumption cars, is the Golf Bluemotion or Fiesta Econetic available in the United States? I ask only because (give or take) 50mpg for the Prius or Lexus seems pretty dismal when you could be talking about 60+ mpg where the Volkswagen or Ford are concerned.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. all cars all years 0-60 and 1/4mile time
    By matheus in forum General Automotive
    Replies: 51
    Last Post: 04-26-2015, 06:29 PM
  2. Gran Turismo 5
    By Sauc3 in forum Gaming
    Replies: 1020
    Last Post: 05-19-2014, 03:16 PM
  3. Really useful performance listings...
    By Egg Nog in forum Technical forums
    Replies: 58
    Last Post: 06-20-2013, 10:45 PM
  4. GT4 whole car list!!!!
    By Mustang in forum Gaming
    Replies: 247
    Last Post: 07-07-2010, 08:06 AM
  5. Hide-Out Index
    By Sauc3 in forum Matt's Hi-Res Hide-Out
    Replies: 59
    Last Post: 06-20-2008, 02:43 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •