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Can't make it up long, steep passes over 62mph in 2004, #9

Discussion in 'Gen 2 Prius Main Forum' started by Steve Goldenberg, Jun 9, 2004.

  1. Steve Goldenberg

    Steve Goldenberg New Member

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    I have no problem on short, steep climbs but when the battery goes down after about 5 minutes, the ICE can only move me at 62mph. Coming down the other side, the battery fills up and I'm OK for 5 minutes going up the next pass. I have a few friend that say they do the same route at up to 75mph regularly. Toyota says I'm in the old turtle mode and that the battery boost is just that and no more. I would like the ICE to keep me going a little faster in that situation.
    Does anyone have any experience in a similar situation?
     
    #1 Steve Goldenberg, Jun 9, 2004
  2. efusco

    efusco Moderator Emeritus
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    Re: Can't make it up long, steep passes over 62mph in 2004,

    Steve,
    I know that many people can't sustain speeds over even 50mph...or 45 at times, in some of those Colorado mountain pass climbs, so if you can maintain 62 I don't think that's terrible...do you find you're slower than all the other traffic or just not able to jump past them when you want?

    Next, you sound like a perfect candidate for additional battery capacity. If you had double or triple capacity it would probably be enough to sustain you over those passes. I know you're handy with electrical mods and there's a very active effort to obtain some additional battery capacity in a Private Yahoo forum I participate in. You can get enough batteries to fill the spare tire well (spare then goes into the 'hidden' space under the cargo area floor) to approximately triple the HV capacity for about $3k installed (very rough estimate). Furthermore, the group is anticipating an overall improvement in mileage from 11-20% with the additional bat. capacity.

    All that said, I can certainly understand where, considering where you live, that lack of that little bit of extra power could be a big frustration over time. Keep us up to date on what you decide to do. I would also be interested in hearing how the Highlander Hybrid will perform under those conditions.
     
    #2 efusco, Jun 9, 2004
  3. Ken Cooper

    Ken Cooper New Member

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    Part of my criteria for purchase of a car is, "will it climb La Bajada hill between Albuquerque (5000 ft.) and Santa Fe (7,000 ft.) at 79 mph without slowing. My new Prius did just fine (you could definitely hear the engine but the car maintained speed - it was a nice day with no headwind).

    It would be great if Prius and Audi could get together then modify Audi's 1.8T turbo engine to run in the Prius. Turbo enhanced engines are perfect for high elevation driving. Normally aspirated engines just poop out as elevation increases / air density decreases.

    If you get a chance, I'd love to hear how your Prius does as it approaches Eisenhower Tunnel on I-70 in that 11,000 ft. rarified air environment. I doubt that any normally aspirated 4 cylinder engine cars up there, while climbing, are able to maintain full freeway speed (my Audi 4000 Diesel, several years ago, felt like it was going to die on the spot heading into that tunnel).

    Regards,
    Ken
     
    #3 Ken Cooper, Jun 9, 2004
  4. tms13

    tms13 Member

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    In principle, the Prius's Atkinson-cycle engine ought to be able to shorten the intake valve opening to get more air into the cylinder without the need for turbocharging (although it sounds unintuitive to shorten the intake time, think of it as reducing the blow-back time, making the cycle more like an Otto cycle). Perhaps it already does (I need to find out how the mass-flow meter works and is used?), and it reaches its limits up there?

    Not a problem here, where very few roads get over 500m or so (1500ft). :)
     
    #4 tms13, Jun 9, 2004
  5. finman

    finman Senior Member

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    I've just recently driven the Eisenhower tunnel (Mem Day). No issues at all. It was 30 degrees and light to moderate snow, did 65 MPH until traffic slowed (inevitable on I-70, but good that traffic slowed, since road conditions could have been icy. just wet this time). Averaged 20 MPG up and the max 99.9 down. Battery level did dip to the very last bar, but never did the engine let up, just kept spinning, keeping a very constant speed (was not using cruise). Came back via Loveland Pass on Highway 6. Still 30 degrees, still snowing, did seem to strain a tiny bit when wanting to go 65, but never held up traffic or thought I wasn't going to make it. Battery level again was at last bar, but all was recharged on the downhills. B mode works well, had to touch brakes only a few times. I LOVE this car. Total miles on that trip 160, averaged 45 MPG (computer). Not bad considering weather and the SUVs getting 15 MPG that I passed! Drive on, drive clean, drive Prius.
     
    #5 finman, Jun 9, 2004
  6. Steve Goldenberg

    Steve Goldenberg New Member

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    I dropped the Prius at Bighorn Toyota today. They will drive it to a Toyota mechanics conference in Beaver Creek tomorrow and then send my car and another over Vail Pass together with the drivers connected with walkie talkies. I will report the results as soon as I get them when I pick up the car on Friday afternoon. (They lent me a Corolla "S" for the few days. It's not anywhere as nice as the Prius.)
     
    #6 Steve Goldenberg, Jun 10, 2004
  7. rockluvr

    rockluvr New Member

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    #7 rockluvr, Jun 10, 2004
  8. bookrats

    bookrats New Member

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    Thanks for posting what you're discovering about the situation, Steve!
     
    #8 bookrats, Jun 10, 2004
  9. Steve Goldenberg

    Steve Goldenberg New Member

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    Thanks Rockluvr. I did miss that thread. I didn't have to stop to charge the batteries. That's absurd. Without the battery boost, the ICE alone was able to maintain 62 mph but it seemed really slow and laborious. One of my friends is certain that he maintains 75mph on the same route. Toyota experts will be making that drive today with my car and one of theirs, side by side talking to each other.
    (What I'm experiencing used to be called "Turtle Mode". That can't be avoided but it would be nice if a simple adjustment let the ICE put out a little more power. I will post the results over the weekend.
     
    #9 Steve Goldenberg, Jun 10, 2004
  10. Cathy K

    Cathy K New Member

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    I've made a couple of trips via I70 from Grand Junction to Denver and back. My prius tops out at about 65 during the stretches where the battery is depleted. However that seems to be enough to keep well up with traffic. Average milage is in the 46-48 mgg range depending on cross-winds, etc.
     
    #10 Cathy K, Jun 10, 2004
  11. rockluvr

    rockluvr New Member

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    Steve,
    Very interested in what Toyota has to say with their experiment. Keep us posted. Thanks!
     
    #11 rockluvr, Jun 11, 2004
  12. Steve Goldenberg

    Steve Goldenberg New Member

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    Just picked up my 2004 Prius from the Toyota Service Dept. The bad news is that there is nothing wrong with my car. All diagnostics and the road test were normal. The car was just not designed keep up top speed on severe mountain passes. The performance equaled or slightly exceeded the Toyota techs "pace" car.
    The only mystery that remains is to find out how my friend makes the same trip at a steady 75mph in his 2004 Prius. I will try to swap cars with him for my next such passage.
    The guys at Bighorn Toyota were all great. They enjoyed my Bluetooth phone demo.
     
    #12 Steve Goldenberg, Jun 11, 2004
  13. Ken Cooper

    Ken Cooper New Member

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    Hi Steve,

    The car swap sounds like a good idea. Your friend just may have developed a driving technique that results in more efficient use and charge of the battery. If so, I hope he shares that with you, so that you might share it with us.

    Look forward to hearing the follow-up details.

    Ken
     
    #13 Ken Cooper, Jun 11, 2004
  14. Wolfman

    Wolfman New Member

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    IIRC, the speed limit throughout I-70 in the mountain passes is 65 or less. What's wrong with 62? I have yet to see very many vehicles make it over these grades, at or above the posted limit. The ones that I have seen, are typicaly big v8's or turbocharged, the latter making them immune to the effects of altitude. I'd say, that your vehicle is performing just fine.
     
    #14 Wolfman, Jun 11, 2004
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