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Is Gen 5 Prius really better-looking than Gen 4 Prius Prime?

Discussion in 'Gen 5 Prius Main Forum' started by Gokhan, May 24, 2023.

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  1. Tideland Prius

    Tideland Prius Moderator of the North
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    It also used higher factory tyre pressures (39/36 psi) and use a different tyre.... Dunlops I think?
     
    #401 Tideland Prius, Apr 16, 2024
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  2. Trollbait

    Trollbait It's a D&D thing

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    #402 Trollbait, Apr 16, 2024
    Last edited: Apr 16, 2024
  3. Gokhan

    Gokhan Senior Member

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    Your calculations were/are wrong.

    First, you should know that you shouldn't round off numbers before you do the calculation. You should round them off afterwards. That is well known in error and significant-figure handling. It doesn't matter at all whether you use mpg or gpm.

    Second, you could easily calculate the wheel/tire-size effect using the nonhybrid numbers, as the same wheel/tire sizes were also tested for the nonhybrid Camry. However, you chose to guestimate it instead, which resulted in additional error.
     
    #403 Gokhan, Apr 16, 2024
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah remember that. Kind of crazy to think they were achieving "eco" status, by merely bumping the tire pressure. I know there's more to it, but that bit...
     
    #404 Mendel Leisk, Apr 16, 2024
  5. Trollbait

    Trollbait It's a D&D thing

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    This isn't for a peer reviewed paper, and you used the rounded mpg figures presented for the cars.

    As I said, I used the 2024 EPA figures to keep with the 2024. There is no 2024 ICE Camry with 16" wheels in the EPA database. The L that you happened to find wasn't sold to the general public in a meaningful way. It existing, and having a separate EPA rating, is not common knowledge.

    With the XLE to L improvement being 9.7%, the Li-ion coulombic efficiency improvement is 3.3%.
     
    #405 Trollbait, Apr 16, 2024
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    I mean, have you seen the recommended PSI for the Model 3? Might partially explain the harsh ride on the earlier models. Not sure if they’ve changed the requirement for the Highland model (it’s using Hankook iON Evo AS tyres)
     
    #406 Tideland Prius, Apr 16, 2024
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    yes, 42 psi.
     
    #407 Mendel Leisk, Apr 16, 2024
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  8. Gokhan

    Gokhan Senior Member

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    I don't know where you are getting the 9.7% from. It is 6.25% (34/32 − 1) for the combined mpg. That makes the Li-ion coulombic efficiency improvement 6.4% (52/46 × 32/34 − 1) for the combined mpg.

    For the city mpg, the Li-ion coulombic efficiency improvement is 11.9% (51/44 × 28/29 − 1).

    For the highway mpg, the Li-ion coulombic efficiency improvement is 7.3% (53/47 × 39/41 − 1).

    The numbers are scattered due to round-off errors. I would take the average of the three and say that the Li-ion coulombic efficiency improvement is about 8.5%. Likewise, the average wheel/tire size improvement is about 5.0%. Therefore, the Li-ion coulombic efficiency improvement is more than the wheel-size improvement for the P205/65R16 vs. P235/45R18 tires.

    2018 Camry brochure
     
    #408 Gokhan, Apr 16, 2024
  9. Trollbait

    Trollbait It's a D&D thing

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    I stated multiple times that I used 2024 EPA figures to keep like to like with the 2024 Canadian ones.

    The 2024 XLE/XSE is rated 31 combined mpg. And that is so going back to at least 2021.
    Compare Side-by-Side
     
    #409 Trollbait, Apr 16, 2024
  10. Gokhan

    Gokhan Senior Member

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    2025 Camry is live on the Toyota website now.

    2025 Camry LE is rated 53/50/51 mpg (city/highway/combined) and priced $28,400.
    2024 Camry LE was rated 51/53/52 mpg (city/highway/combined) and priced $28,855.

    2024 Prius LE is priced $27,950.
     
    #410 Gokhan, Apr 17, 2024
  11. Tideland Prius

    Tideland Prius Moderator of the North
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    Wow. They’ve kept the pricing in check? Or did the 2024 Camry have a price hike?
     
    #411 Tideland Prius, Apr 17, 2024
  12. Trollbait

    Trollbait It's a D&D thing

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    Looks like the 2023 had an increase of $1500 to $1700.

    When comparing between the current and 2025 Camry, I noticed that all the current trims have Li-ion. I'm guessing it happened around the time the XLE/XSE combined went from 32 to 31mpg; the change triggered retesting. Some the difference between trims is all wheels, tires, and the little bit of weight.
     
    #412 Trollbait, Apr 17, 2024
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  13. Gokhan

    Gokhan Senior Member

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    I'm not sure what you mean, but Li-ion is more Coulombic-efficient than NiMH, and you would get a higher mpg with Li-ion than with NiMH as a result for a given wheel/tire size. Yes, they all went Li-ion at one point, but we don't know what was retested and what wasn't. Also, as I've been emphasizing to you over and over again, the uncertainty in the EPA numbers is huge; so, you are comparing apples to oranges, especially if you compare something that was tested in 2018 to something that was tested in 2023, likely in a different laboratory by different people.
     
    #413 Gokhan, Apr 17, 2024
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