X15 fuel mileage

Discussion in 'Volvo Forum' started by 905trucker, Nov 13, 2022.

  1. 905trucker

    905trucker Bobtail Member

    4
    1
    Nov 11, 2022
    0
    I have an 2019 Volvo VNL 760 with a X15 Cummins

    X15 500hp 1650 torque
    Gears 3.55
    Eaton automated 13 speed

    I can only get on summer fuel average 6.8 to 7.3 mpg , seems to be A little better running 98 kilometres an hour.

    Is this normal? I was told to try the following

    Turn HP down to 450
    Get valves adjusted top end
    Any suggestions or is this the best it gets


    ((My son has a 2022 Peterbilt ultra loft with the same set up getting 8 to 8.8 running the same lanes the same speed doesn’t make sense to me)))
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Short Fuse EOD

    Short Fuse EOD Road Train Member

    1,616
    4,403
    Jul 29, 2015
    Fortuna Faviet Fortibus
    0
    I’m getting 5.9 summer 3.25 rears 565/2050 I set cruise often at 66mph. Flats lands

    mountains and boarder produce 72mph arround 5.4 summer.

    75-77 mph 5.0 and 4.9 respectfully
     
  4. Midwest Trucker

    Midwest Trucker Road Train Member

    5,576
    19,532
    Aug 31, 2018
    0
    Is yours a performance and his an efficiency? I know you said same specs but is his an automatic?

    His X15 would be a newer generation of that engine. I recently sold a 2018 t680 with 3.55 with x15 efficiency 450 and with 13 speed.. It would do 7.5 on its best days. However, I have 2022 and especially 2023 t680's with x15 efficiency doing 8.5 even 9 but with 2.79 autos. 7.5 is a bad day for them.
     
    KB3MMX, Siinman and baha Thank this.
  5. KB3MMX

    KB3MMX Road Train Member

    2,957
    2,478
    Dec 29, 2014
    Orrstown, PA
    0
    3.55 is way too fast rears for these modern X15 motors to get mpg. I'd change to 2.85 - 3.08 rear with a 1850 tq uprate.
    Your engine will pull better and get better mileage... And live longer.
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  • Draft saved Draft deleted