Turning down heavy specs

Discussion in 'Canadian Truckers Forum' started by Abovealltrucking, Nov 15, 2020.

  1. Abovealltrucking

    Abovealltrucking Bobtail Member

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    Nov 15, 2020
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    Does some one has experience with heavy spec truck (detroit 16 motor with 550 hp) lowering to 500 hp and decreasing gear ratio?

    By doing this, was this heavy spec truck started giving normal highway tractor mileage ? Or was it still burning fuel like a heavy spec truck will?

    any feedback appericiated.
     
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  3. Phantom Trucker

    Phantom Trucker Medium Load Member

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    Hard to say if that’ll solve your fuel milage problem. One thing is for sure, switching out rear end gears will cost more than it’ll ever save.

    There’s other contributing factors you could look at as well, the wrong type of tires for your application can be a fuel milage killer. Engine components like a leaky air to air, valves out of adjustment, injectors, etc, aren’t good either.

    What are you getting for MPG? And is it that number actual miles driven divided by gallons added or are you getting that number off the dash?

    Also, can you provide some details about your operation? Type of truck, trailer, weight, part of the country you run in etc. (Your milage might not be too far from the norm).
     
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  4. AModelCat

    AModelCat Road Train Member

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    Why neuter a truck meant to do work?

    Buy something that's already setup for what you need it to do.
     
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  5. uncleal13

    uncleal13 Road Train Member

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    Just run it at the speed it is geared for and it’ll do fine.
    I regeared a truck once, cost me $5,000 and only saved 0.3 mpg
     
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  6. mudflap77

    mudflap77 Heavy Load Member

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    How much of a change in gear ratio?
     
  7. uncleal13

    uncleal13 Road Train Member

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    4.10 to 3.58
     
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  8. mudflap77

    mudflap77 Heavy Load Member

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    If that .03mpg took you from say 5.5mpg to 5.8mpg @ $3.00 fuel over 100,000/yr, you would be saving just shy of $2500/yr.. so a 2 yr payback.. Not a total waste of money as long as you keep the truck past 2 years.
     
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  9. Marmon110P

    Marmon110P Light Load Member

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    Theres lots of proof out there that a driver can make up to as much as 30% of the fuel economy of the truck. If you dont know how to drive it, then your costing yourself more $$. I suspect that if you think turning down the HP on an engine will help fuel economy, then your not gonna get good results no matter what you do...
     
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