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Mileage hit vs Prius is too severe

Discussion in 'Prius v Fuel Economy' started by web1b, Oct 26, 2011.

  1. web1b

    web1b Active Member

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    The v is larger and 230lbs heavier, so the mileage cannot be identical to a regular Prius, but the cut in mpg is pretty severe.
    It is only 1 mpg higher than the 2012 Camry Hybrid which has a much more powerful engine.
    I feel like the v may be under-powered and the small engine could be struggling with the extra weight vs the standard Prius resulting in lower MPG.
    If you just want a roomier interior for passengers and a quieter ride than a Prius offers and don't need the cargo room for bulky items, I think the Camry Hybrid will be a more enjoyable vehicle to drive and ride in than the Prius v for only 1 MPG penalty.
    It wouldn't surprise me if the current engine is a stop gap until a more powerful and more efficient engine comes out for the v (maybe put Camry Hybrid engine in if not an all-new engine).
     
  2. cwerdna

    cwerdna Senior Member

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  3. web1b

    web1b Active Member

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    Re: Milege hit vs Prius is too severe

    And the drive ratio is to compensate for the weak engine so the acceleration hit could be minimized as the weak engine struggles against the extra weight. It is a reason for the issue, but not justification.

    Make a Camry Hybrid wagon with the same mileage or a 1 mpg hit vs the sedan and no more reason for the V.
     
  4. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    Re: Milege hit vs Prius is too severe

    I imagine you didn't get a larger powertrain simply because you'd be at the limit of the platform as it is.

    Isn't a Camry Wagon just a Venza?
     
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  5. web1b

    web1b Active Member

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    Re: Milege hit vs Prius is too severe

    They could make a Venza Hybrid, but I think the Venza is bloated out with extra size and weight more than a true Camry wagon would be, so the mpg hit would end up being more than 1 mpg if it was a Venza.
    They can either make a new engine of similar size to the current Prius engine that has more power to handle more weight without so much effort or they could have built on the Camry platform and used the existing larger motor.
     
  6. quantumslip

    quantumslip Member

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    Re: Milege hit vs Prius is too severe

    i wonder what would have happened if they left the drive ratio the same; it would be akin to having a larger driver or a passenger constantly in the car. Empty it might have been fine but load it up and you might see problems. nevertheless we would still see a mpg drop even if it weighed the same because the drag coefficient is higher for the v. what % of the drop could be attributed to the drive ratio, i'm not sure.
     
  7. web1b

    web1b Active Member

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    Re: Milege hit vs Prius is too severe

    People would have complained that it felt way too slow getting on the highway if they didn't change the ratio. It is still a bit slower to accelerate than a Prius even with the shorter drive ratios, but it's close enough that it isn't really that noticeable.
     
  8. Tideland Prius

    Tideland Prius Moderator of the North
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    Yeah but the cargo capacity just can't compare to the TCH. It's targeting a different buyer. The Camry is more likely one with older kids or empty nesters. The Prius v is for younger families that are looking at a Mazda5 or Kia Rondo like vehicle and don't want the Sienna or Odyssey. The Prius is 2x the mileage of the Mazda5 with only one fewer seat.
     
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  9. web1b

    web1b Active Member

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    I think I remember the Toyota Matrix also having a huge mileage difference vs the Corolla sedan with the same engine. I think part of that was different gear ratios also.
     
  10. fuzzy1

    fuzzy1 Senior Member

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    No one is mentioning air drag? With a larger cross section and a somewhat less aerodynamic shape, this has to be an additional factor.

    From past discussions, I thought the HSD system's fuel economy should be much less sensitive to gear ratio changes than are traditional powertrains.
     
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  11. GasperG

    GasperG Senior Member

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    Re: Milege hit vs Prius is too severe

    What final drive ratio? What is the RPM in Prius at top speed with foot off the accelerator? maybe 2000 RPM? Of course if you choose to sustain this speed you will have to floor it and RPM goes higher.

    Not saying that it's not true, but maybe with heavier car and bigger wind resistance, they found different drive ratio more efficient (it could be also performance issue)

    Where did you find this data? If this is true then ICE must spin at lover threshold speed than in a Prius (45 mph), but not necessarily if they changed this in software like in PiP.
     
  12. web1b

    web1b Active Member

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    Drag doesn't explain why mpg is so close to the 2012 Camry Hybrid that isn't more aerodynamic and has a larger and much more powerful drivetrain. The V is sill pretty aerodynamic.
     
  13. AtoyotA

    AtoyotA Junior Member

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    Ah, but the Camry is more aerodynamic in that it has a Cd of 0.27 compared with the Prius v value of 0.29. As others have said, I believe the hit in mileage compared to Prius is due to; increased weight (at least 230 lbs), larger Cd (0.29 instead of 0.25), and larger cross-sectional area (about 1 inch wider and 3 inches taller).

    And yes, it has 10% higher gearing than the Prius, i.e., 10% more rpms, but I have no idea what effect that would have on mpgs.
     
  14. JamesBurke

    JamesBurke Senior Member

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    The added weight of the Prius V (anagon) would be 250 + the increase in max load about 90 lbs I think. Wouldn't 340lbs be like an extra 10% vehicle weight? There's the why change the gear ratio. Add this kind of weight to a regular Prius all the time and see where your MPG, power, and acceleration go.

    250 lbs is about the weight of the average american in my area and 340lbs not uncommon.
     
  15. web1b

    web1b Active Member

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    Prius V weight starts at 3274lbs and has combined horsepower of 134.
    The Camry Hybrid weighs more. A minimum of 3414 pounds and has combined horsepower of 200 and only gets 1 mpg less in city and highway. That's a large amount of added power and added weight the Camry Hybrid overcame to attribute it all to the difference between .27 and .29 vs the V.
     
  16. dhanson865

    dhanson865 Expert and Devil's advocate

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    If you happen to have a v (Wagon) you can surely get better gas mileage by replacing the OEM tires with something that has lower rolling resistance.

    You might even consider 15" or 16" wheel downgrades if you have 16" or 17" wheels on the car now.

    I'm collecting OEM tire info here
    http://priuschat.com/forums/prius-v...-wagon-oem-tire-rpm-speedometer-accuracy.html

    Once we get speedometer accuracy data we'll know how much smaller a tire we can get away with for those wanting to get better fuel economy by switching tire sizes.
     
  17. cycledrum

    cycledrum PSOCSOASP

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    1) Mileage loss seems severe, but look at it this way -

    Assuming Prius and v get their average, after 400 miles, you'll pump in 8 gallons on Prius, but only 9.5 gallons to refill the v. Is 1.5 gallons diff. after 400 miles really something the average American will pass out over?? No. Our gas unfortunately is subsidized, so an extra $6 after 400 miles will not break the typical driver.

    Consider all the CR-V's, Equinox, Rav4, and so on, ... they're 25 MPG at the pump. Their blowing away 16 gallons in 400 miles. Putting 8 more gallons in than Prius. These are the ones we need to shift over into Prius v's, because they will like the roominess of it. Will they be ok with the power? I don't know. We'll see.

    Plot out gallons / mile (y) vs. MPG's (x). The derivative is a - (1/x squared) function. IOW, as x (your MPG's) get's small the gallons per mile climbs at increasing rate (squared). At high MPG's ( maybe over 50) , change in gallons used flattens out.

    Yeah, I know we need to get people off gas altogether, but it's a process and has to work for picky car buyers who will buy a small to midsize SUV in a wink.
     
  18. Tideland Prius

    Tideland Prius Moderator of the North
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    cycledrum has nailed it.

    The Prius v isn't meant to sway buyers from the Prius liftback. It's meant to bring in new ones from the current crop of cute-ute (or compact) owners. The ones that like the higher seating, large cargo area and compact size. The difference here is that the Prius v almost doubles their mileage and gives them more passenger space. The only thing they give up is AWD (and most are the slip n' grip types anyway).

    If the Prius v proves to be popular enough, I hope Toyota considers a 4WD-i option (rear elec. motor) on the next Prius platform for the 2nd gen Prius v. It may require a larger 2.0 litre engine (I hope they can continue to refine and improve the electric side or things to avoid that bump in displacement and reduce weight of course).
     
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  19. sipnfuel

    sipnfuel New Member

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    If the Prius v has the same PSD, and the same top speed as the regular Prius then the overall drive ratio is the same. i.e. if there is a different final drive ratio, it's probably because they have different tire radii.

    But I couldn't find information for the top speed of the Prius v.
     
  20. usbseawolf2000

    usbseawolf2000 HSD PhD

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    C&D said the top speed is 103 mph.

    It'll be interesting to see how the 2.5L HSD from TCH would perform in Gen2 Prius v.