Highest RPMs should go?

If you want to know your practical operating range, hold the accelerator pedal to the floor for a couple seconds to show your rpm limit, probably 1800 to 2100 rpm for most modern engines with a stock tune.

The reality of that is, that's the maximum rpm your engine will achieve at full throttle, but not your optimal operating range which is below where the horsepower curve flattens out, 1600 to 1700 rpm for most modern engines.
The engine will rev higher, but won't make any more power, sometimes loses hp over that point.

Jakes produce more brake hp at higher rpm, so I would agree that 2200 rpm is safe for most engines and won't cause a lot of unnecessary or premature wear on the engine.

Back in the stone age, it was known that the valves would float around 2600 or 2700 rpm, except 2 stroke DD's, and that a truck from the factory would be governed at 2150 or 2250 rpm when it got to the dealership.

The routine was to put about 50k miles on it and bring it in for top end set up.
At this point, the crew I ran with would grab their once a year load and visit certain select certified Cat and Cummins dealerships out west in mountain country where they tuned the engines to pull at high altitude then head back until it was time for another tune up, within manufacturers specifications, the high end of what your warranty allowed.

 

Agreed, working hard at low rpm's hammers the bottom end, puts a lot of unnecessary stress on things.

 

My Cascadia shows a warning when the RPMs get somewhere above 2300 or so. It just puts a "Reduce RPMs" in the display that shows time, temp, heading.

I don't know why Funkliner tachometers have no operating range marked on them like every other model of truck I've ever driven. They don't even have a red line on them. I guess that might be a $500 factory option.

 

I think it allows you higher rpm if you have the engine brake on...
But, I wouldn't know much about that...

No, it was a 12% grade going down in 5'th gear. Caught me off guard at how fast the rpm could climb in 5'th with the engine brake on high...

 

Yeah, it is. I don't remember what the owners manual says for DD15... Not to exceed 2400 with engine brake?

 

Something like that. Dash starts complaining to you at about 2300, too

 

Good to hear this from a professional. I was taught to upshift at 1600... sometimes, when I'm impatient, I push it to 1700-1750. I'll keep it strictly below 1700.

I've never let it go past 2,000. I'm surprised he didn't blow it up.

 

^^^ X2