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Prius II towing

Discussion in 'Gen 2 Prius Technical Discussion' started by jmaxe444, Jul 3, 2011.

  1. jmaxe444

    jmaxe444 New Member

    Joined:
    Jul 3, 2011
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    Location:
    Florida
    Vehicle:
    2009 Prius
    Model:
    II
    Hey there. I have a 2009 Gen.II that I have installed a towing hitch on. I would like to upgrade a couple of things. I would like to put on air shocks in the rear ( just to add strength and stability ), and a temp. guage so as not to over heat the tranny when towing. I know, why put a towing hitch on a Prius? Well, I put a cargo carrier on the back and I also tow a small skiff that weighs around 1500lbs. The back drops 1.5" when the boat is on. Sometimes it just has to be that way. Any input on either of the two areas of concern would be greatly appreciated. Thanks.
     
  2. jpadc

    jpadc Type before I think too often

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    Location:
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    Welcome jmaxe444 to PriusChat...

    Lots here on towing as many of us have/do. I'm not sure on the air shocks front, but do a search and see. Also do a search for Scangauge for temperature measurements and many other useful things

    Google Advanced Search
     
  3. bc104

    bc104 Junior Member

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    Mar 6, 2007
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    Location:
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    2007 Prius
    I'm sure searching through the site you'll find a lot of people recommending that you don't do this, but personally I think it would do fine for short hauls, although 1500lbs sounds like a lot. I'm very interested to learn about air shocks or some sort of a helper spring setup. Any weight within the recommended range makes the car sag. Even on my '94 Toyota pickup which was a 1/2 ton truck it bumped the tires in the wheel well when loaded down with a few hundred pounds. I had to put extra springs in that as well. I wouldn't mind sacrificing ride for usability.
     
  4. RobH

    RobH Senior Member

    Joined:
    Sep 18, 2006
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    Location:
    Sunnyvale, California
    Vehicle:
    2006 Prius
    In California, a trailer over 1500 pounds must have brakes and a breakaway switch. A breakaway switch is a mechanism that applies the brakes if the hitch fails.

    I've towed a 560 pound travel trailer quite a few miles with my Gen2 Prius. It wasn't any different that what I imagine it would be like with a Corolla. The reason I mention the Corolla is that Toyota rates it for towing, while the Prius has a zero tow rating. My guess as to the difference in ratings is that the Prius could exhaust the HV battery on a long uphill pull. In that case, you'd only have the gas engine for power, which is about 65 HP. I've never experienced the problem, but then I haven't tried any long uphill pulls.

    The issue of transmission heating is different with the Prius than with other automatic transmission cars. Other cars use a fluid coupling in the transmission, and heavy use causes heating just by the mechanical process of stirring the fluid. The Prius is not subject to heating of a fluid coupling, as it doesn't have one. But it does have two electric motors in the "transmissiony thing" that obviously have to work harder under heavy load. One of the weak points of the Gen1 Prius is that the windings of those electric motors short out. Later Prius are better, but it is still a concern. The transmission fluid breaks down with age and heavy use. It should be changed more often if you do much towing. You can use a ScanGauge to monitor engine coolant temperature. The ScanGauge can't see the messages about inverter and MG1/MG2 (transmission) temperatures.