X-15 Cummins thread

Thanks for the info dude, question about the powerband on that motor, does it pull hard right off 1000rpm to 1700rpm?

 

Not that I notice?

 

Just curious, we have some guys with the same motor, and they're complaining they don't make any power 1000-1400rpm, they say they have to rev them up to 1500-1700rpm to make power. I've heard this before on forums, but never seen it in person. I'm managing the Maintenace department for the company in Calgary, and these trucks are in Winnipeg, so I can't take one for a drive myself. Cummins of course says there's nothing wrong.

 

We run our one X15 at 1500 RPM all the time. I actually should have ordered it with lower gears since we don't even use 18 on the 18 speed, but that does give us one more hole if we need to go a little faster. I honestly don't like running the truck below 1200 at all and I do feel it pulls the best at 1350 to 1500. Because of the way we run, we didn't really see a fuel usage difference between running it at 1200 RPM or 1500 RPM.

 

100% fact Jack …… happened to mind in the same sequence.

 

That’s what mines runs it’s best fuel mileage. On a pull when it the rpms start dropping, right about 1400 the torque kicks in and it holds it. Regardless, I despise these emissions ### aparts, but have don’t have much of a choose in Commiefornia.

 

Yes they pull hard down low! The cavite: just because it can do it, doesnt mean its should be done. As others point out 1450 1500 is fairly safe at full power, while keeping watch on pyro, oil and water temperatures. The key to engine life and economy is keeping the pyro below 75% to 80% of highest temperature observed, even if it requires downshifting couple gears. You'll notice quite an increase in fuel milage

 

Hello, new to the cummins world here, I'm used to Caterpillar and detroit.

The boss bought my a 389 with the X15 productivity, 565/1850. So far I like it, except for one thing, the sketchy/violent throttle response when your trying to move slowy. The go pedal is way too responsive, it feel like putting a rubber band between the go pedal and the mecanical injection pump on a old engine Nothing happen for the first half inches, then..BAM..the engine is already close to 1300 rpm. Not that usefull when you are trying to get unstuck in snow.

Do cummins can adjust the sensitivity? Its a truck, not a race car

 

It could be the fuel pedal potentiometer. Paccar has had problems with them. Most of the time it's the plug but not always.

 

Not an issue in my International.