X-15 Cummins thread

Discussion in 'Peterbilt Forum' started by KB3MMX, Feb 26, 2018.

  1. Shorthorn

    Shorthorn Bobtail Member

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    I'm in a 2020 389 pete it has the cx15 565 hp cumming and its a dog for some reason at 71mph its at 1500 rpm and it falls on its face .I have to run in 17th at 1700 rpm to get any kind of pulling perfomance..it also has very little throttle reponce..and very bad turbo lag ..some advice would greatly appreciated..
     
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  2. BigHossVolvo

    BigHossVolvo Road Train Member

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    Does it have the PACCAR fuel/water separator or the Davco? Also what is the highest boost pressure you are seeing?
     
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  3. Hegemeister

    Hegemeister Road Train Member

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    Possible the speed may be limited to 71?
     
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  4. Goodysnap

    Goodysnap Road Train Member

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    Sounds like geardown protection?
     
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  5. Diesel Dave

    Diesel Dave Last Few of the OUTLAWS

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    The company I haul for and a truck identical to yours, they checked everything and still ran like crap. Finally they decided to run the over head and it solved the problem. Go figure..... brand new truck and they can’t adjust the valves. Hope this helps.
     
  6. AKDoug

    AKDoug Medium Load Member

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    I just put a 2021 T880 on the road today with a 500hp "productivity" series X-15 and 18sp manual. Not much info out there so we'll wait and see. Runs smooth and has excellent cold start capabilities. Seems to have plenty of power for what we use it for. My driver was very happy with the truck/engine/trans combo.
     
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  7. Goodysnap

    Goodysnap Road Train Member

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    I agree a good choice.

    The X15 series has had minimal issues thus far. Occasional random part failures but no pattern failures across the board since its release.
     
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  8. AKDoug

    AKDoug Medium Load Member

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    I sure hope so. It replaced a truck with a CM870 ISX that we've had relatively few problems with, but at 700K it was complete overhaul time or put the truck into another job that only gives it 10K miles a year. CM870 has had the EGR cooler and turbo replaced in that time span, both of which we did ourselves. Not a big deal considering the dollars it brought in over its life.
     
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  9. petefan4000

    petefan4000 Light Load Member

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    One article on TruckTrend states that this engine is DOHC.
    Weird because another article, also on TruckTrend, reveals that this engine is actually SOHC.
     
  10. Goodysnap

    Goodysnap Road Train Member

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    CM870 and CM871 are DOHC. One cam valves one cam injectors as the injectors are mechanically actuated.

    With commonrail injection the CM2150 and newer engines are single cam. No need for cam with higher fuel pressure generated by the HP pump and electronic injection.
     
  11. TheFonz

    TheFonz Bobtail Member

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    2020 389 with a 565 x15 with a reoccurring coolant leak on that line that runs in the passenger side frame rail. Can’t tell if it’s the metal section or the rubber sections or to where that line runs with out really getting under the truck. Any one know where it goes or which line is likely to be the culprit?
     
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