Why/when to spec a "mult-torque" engine?

Discussion in 'Experienced Truckers' Advice' started by seamutt, Jun 30, 2021.

  1. seamutt

    seamutt Bobtail Member

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    Can anyone explain these to me? I can't seem to find much information on them, and this single paragraph is basically it:

    "Multi-torque models allow the engine and transmission to work together to select the optimal torque curve. This improves fuel efficiency by only providing maximum torque in the top two or three gears, which encourages the driver to operate in the highest available gear for the highest efficiency."

    So do the engine and transmission onboard computer(s) sense a high load situation and only switch into high torque mode in appropriate situations, or is the higher torque output - and also presumably its increased fuel usage - always active in the high gears? Are these engines basically made for heavy hauling (my wild guess), or might they also be useful for general purpose hauling? Are they notably more expensive? Harder to maintain? Etc..

    Edit: Oh crud, a typo in the title and I can't edit it or delete the post. Sorry about that. I hope it won't screw up topic searches (it probably will).
     
    Last edited: Jun 30, 2021
    Reason for edit: corrections
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  3. abyliks

    abyliks Road Train Member

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    Just more useless bean counters BS for seat warmers, your right foot makes the difference on that, always get the big motor, and drive it gently
     
  4. Rubber duck kw

    Rubber duck kw Road Train Member

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    Specially designed for those who simply mash the gas and close their eyes.
     
  5. Six9GS

    Six9GS Heavy Load Member

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    You mean there's more to it than that?!?!? o_O:eek::D
     
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  6. Rubber duck kw

    Rubber duck kw Road Train Member

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    Only if you want there to be apparently.
     
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  7. prostartom

    prostartom Bobtail Member

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    I started out in 2003 driving an International 8100 single axle with a Cummins M11 and 10sp trans. It was 370hp and I believe 1050/ 1150tq. I loved that motor, floor it going up hill and after about 5 seconds you could hear the boost kick up and usually I didn't lose any speed after that. It was pretty rare that I needed to downshift, not many trucks ever passed me on a hill, I was only grossing about 50k max though.

    That truck was dam reliable, never left me stranded. Worst thing that happened was I lost the water pump in CT, was still able to limp it back to Baltimore with a couple water stops on the way.

    Finally got rid of it last year, rookie broke something in the tranny and the boss didn't want to put any more money into it. Took it to the auction with 600k miles on it and it fetched more money than the 2011 Prostar that replaced it. The Prostar had less miles but it was a MaxxForce motor, and it left me stranded a couple of times.
     
    Last edited: Jul 1, 2021
    Reason for edit: Incorrect year
    Bean Jr. Thanks this.
  8. Brandt

    Brandt Road Train Member

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    They were for fuel mileage I would say and probably save wear and tear. It was probably more of a company spec truck option. Because new drivers would just put pedal to the floor to shift gears even in low rang and you don't need that much power at stop lights.

    So the driver could put pedal to floor and get less torque but still get more pulling power when needed for pulling hills. I don't know if it saved much fuel. I don't think they spec that much anymore because the new automatic transmissions can talk to engine or it can actually control the engine and they seem to limit the torque automatically in low range.

    Freightliner DT12 auto transmission can sense the load and it had GPS with Hill locations. I see drivers today at stop lights and you them giving the truck so much power the cab torque. The DT12 transmission I'm driving won't let the engine put that much power to the wheels when empty.
     
  9. Rubber duck kw

    Rubber duck kw Road Train Member

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    I talk #### about a split power/torque engine like this but the old N14 select plus set at 375/450 we swapped in my dad's 359 is getting him about 6.8mpg, as long as he isn't running flat out 80mph. That's lower loads running flatbed eastern Iowa to Denver.
     
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  10. bzinger

    bzinger Road Train Member

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    The way I see these apes drive these days if I was a fleet owner every step of the acceleration process would be controlled .
    With most its hold it on the floor and pound the piss out of it ..and then cry that the truck is a pos .
    My 13 cascadia has 947k on it looks dam near new in and out and barely has a sqeauk.
    Why? Because it's been well cared for and hasn't had the hell beat out of it .
     
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  11. Coffey

    Coffey Medium Load Member

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    Ops someone already beat me to the punch
     
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