X15 Efficiency vs Performance

Hopefully oil dilution will be less of an issue as regen times have increased to around 100 hrs or more run time. Without a doubt units that get DPF neglect will end up with frequent regens and overfull crankcases as the engines get some age to them. A big change to keep in mind for sure.

 

The x15 Efficiency is marketed as a lower rpm engine
X15 Efficiency Series (2020) | Cummins Inc.

What’s the optimum “lower” rpm range for it, those with experience with this engine?

 

I have a E and run it at 1300 on avg. on the flats, and will drag it to 1100 on pulls, it pulls good there and the torque curve is strong in that rpm area

 

I have the performance, it's made a odd noise since day one, sounds like a bad plug in a gas engine, at lower rpms, higher rpms it goes away. 235,000 miles now and it's still there. Pretty much just ignore it, after reading about some issues I'm now wondering if it is a bad head gasket? I did have a coolant leak when new at the heater hose clamps, fixed that, but still have to add coolant occasionally, my company says it's leaking out the weep hole on the APU water pump, which you can see it is, so hopefully that is all, no coolant in the oil. But I am curious about it, I was thinking of buying the truck from my company, now I don't know. It's in a 2018 579 , 18spd, pulling tankers.

 

2020 ISX1 efficiency series , whens this thing come to life or does it, doesn't seem to be able to hold a speed on the pedal or cruise , starting to miss the paccar, only have 8300 miles so far,

 

Hey! I'm currently looking at the same set up but with 336 rears. What speeds are you running at? Where do you usually rest your revs for max fuel efficiency? I'm gonna be pulling reefer from the PNW down to TX.

 

Your truck will do 65@1380 70@1450

 

18’ T880 with 500 / 1850 efficiency engine with a “removal of stuff”
3.90 rears + 18 speed

450,000 miles so far

Average 5MPG pulling 80-100k

Just got 2 new trucks and time will tell which is better.
One has 565 / 1850 performance
Two has 605 / 2050 performance

 

What ratio on 565 and 605

 

Your efficiency is ex or productivity series