All you need to know about TOWING!!

Discussion in 'Gen 3 Prius Technical Discussion' started by Bryan L, Apr 27, 2021.

  1. bisco

    bisco cookie crumbler

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    maybe yearly tranny oil analysis would be a good idea if you tow regularly
     
  2. fuzzy1

    fuzzy1 Senior Member

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    Where?

    I had understood that all the ratio changes were from changing the relative RPMs of the ICE, MG1, and MG2. None of the mechanical gearing, or links between gears, changes.

    And so far, we have no indication of any such RPM ratio changes when climbing uphill.
     
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  3. ChapmanF

    ChapmanF Senior Member

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    I think the way I read what rj wrote was two parts, "technically it does have gears" (yes, yes, there are gears in there, just gears that are in constant mesh and never shift), and the transaxle ratio overall does change according to load (that's what makes it a CVT, even though the only changing that happens is in the width and timing of electrical pulses).

    I guess there'd be a way to read rj's comment as saying the gears change ratios, but again that would just be wrong, and I think rj understands the transaxle better than that, so I didn't read it that way.
     
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  4. Pete44

    Pete44 Junior Member

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    Finally a post with some towing data !!

    Anybody have any detailed info ??: I'm going to be towing a 500 lb trailer (loaded total weight will be 500 lb) through the Colorado mountains at higher altitudes (up to about 11k feet). I've got a ScanGuage2.

    The gentleman who was kind enough to post all this experience was super helpful.

    If anyone has any more specific info, it would be really appreciated:

    1) I've got a scanguage 2 and will be monitoring temps. Don't know what specific upper limits I should be worried about. Anyone know what specific ones you'd watch ? (I've been monitoring usual temps for Engine coolant temp and the two inverter temps)

    2) I don't understand what MG1 and MG2 are. Anyone help with these temps? Upper limits tolerable?

    3) I don't know if monitoring the HV battery temp is important, also.

    Could someone, anyone, give some idea of what temps would be most useful to monitor? (which ones to have on the display?) I can periodically switch to check other temps, but only have 4 temps available for constant monitoring).

    Really amazingly tough to find any numbers on here as to what is the absolute (short-term) upper limits on these temps, to be able to see if I'm going to damage the systems or not. I know it'll be harder on the drivetrain, but wondering what specific temps I'd need to watch for to know if it's really "not ok".

    Thanks for any detailed numbers on which temps and what the upper limits of "ok" would be on steeper grades in high altitude (higher altitudes make for less cooling ability).
     
  5. PriusCamper

    PriusCamper Senior Member

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    Monitoring MG1 & MG2 temps means monitoring how hot the electric motors in your transmissions get. If you can get a sense of those temps on a hot day without towing, you'll be able to be more comfortable monitoring those temps when driving with a trailers. And 500 pounds is a very reasonable load... Things get sketchy once you get up above 1500 pounds of a load.
     
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  6. rjparker

    rjparker Senior Member

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    The car will run the various coolant temps within 10f of normal most of the time. You are not likely to overheat anything until a water pump or fan breaks, at which time you will get a dash warning probably faster than you would notice a gauge since you are towing. For example 195f engine coolant may rise to 205 within a minute under heavy load. The radiator fans kick on and it lowers a little. Bad pump or fan and you will have a warning a minute later under heavy load. The same for your inverter and migs. The hv battery fan will speed up but if it fails or is clogged, you get a warning and battery power is reduced. Running ac and keeping the rear vents open helps in hot weather.

    To me the biggest risk is not monitored, eg brake fade. On a long mountain downhill with runaway truck exits, the regen quickly fills the hv battery and no longer aids the brakes. You put it into B mode for engine braking but there is not much there so the friction brakes do more work generating heat. Especially if total passenger, luggage and trailer weight is significantly higher than 950#.
     
  7. fuzzy1

    fuzzy1 Senior Member

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    What car model are you taking?

    Your profile says your vehicle is "Other hybrid". But MG1 and MG2 are specific to Toyota's HSD-system hybrids. If you have a different type of hybrid, this likely doesn't apply.
     
  8. Tombukt2

    Tombukt2 Junior Member

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    funny stuff i tow a Floe 8/57 W Cub cadet rzt 54 fab deck mower my push gas can etc all the effin time .. 270k head gasket not due to towing either. never strained ever pulling this Floe trailer..my 1nz can too.. yaris and corolla use it too. getting ready to buy another Floe trailer ..
     
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