Anyone have firsthand experience going from 22.5's to tall rubber tires?

The torque chart, and Different HP settings.

 

@Rideandrepair

Problem is the list doesn't tell you anything about the power curves for each individual engine, only one of the 455 hp engines.
I imagine they're similar in many ways, but not identical.

From the chart you posted, your economy range is 1500 rpm and under, and the top end of the useable power band is about 1650 rpm where it stops making hp and goes flat.
This particular engine is meant to be operated between 1100 or 1200 rpm and up to 1650 rpm.
It will probably run up to 2000 rpm, but everything over 1500 rpm could be considered wasteful of fuel, and anything over 1650 rpm is beating a dead horse.

I'm particularly fond of long flat torque curves where potential for economy remains fairly constant through most of the rpm range, like on the lower torque engine on the left.
Notice the low torque engine's torque line doesn't start dropping until 1700 rpm, meaning your still in the reasonable range of economy and on the edge of the waste zone.
If you do your cruising on the flat part of the torque line you're in the economy range, but as we all should know and understand, the faster you go the more fuel you use.

 

My 12.7 is supposed to be 1350-1650, from what I’ve always understood. It seems to drive best at 1500, right in the middle of torque band, but gear best mpg at 1375, just above the minimum. I see torque drops off on dd15 after 1500. Seems to Me unless in the hills, it would still do well on economy. I’ve always questioned the idea of an engine that’s made to be Lugged. Newer ones even more so, I’m curious, how much mpgs would improve, if He ran it under 1500 or better yet 1400. Driving slower, working less, but pocketing more. Why would Crete spec them like that? What speed does it run at 1500, I wonder.

 

That makes sense,it’s set up just right, leave it alone. 65s not so bad.Fuel economy is Maximized. What’s not to like? I just realized, you’re at it again, looking for things to spend money on, Lol. I’ve got an old Freightliner for you, needs an OH !!!! Just kidding!!! Good mpg, that’s where it’s at, you’ve got a good set up.

 

I don't understand your thinking. Those dyno charts tell me that they're the same motor, except one has more boost available below peak hp. That also shows as roughly 50 more hp available below peak. That means more acceleration. What else I see is that from peak tq on up, both versions are rapidly defueled, preventing turbo overspeed. Those dyno charts aren't natural for an engine.

What do WOT numbers have to do with cruising performance?

I'd be more interested to see bsfc #s at various rpms & throttle %s to figure best operating speed.

 

Yes, they are the same engine, both are 600 hp but with different programmings.

What those curves tell me for any engine is the amount of torque and horsepower available at any given rpm through out the power band from an idle to the point where the hp peaks and goes flat, the engines intended operating range that it is meant to be operated in for peak performance and efficiency.

Could you please explain how you deciphered better acceleration, rapid de-fueling and turbo over speeding from those dyno charts?
Always willing to learn from the pros.

 

Definitely not gonna call myself a pro...

HP = work done = acceleration, so since the 600/2050 motor has about 50 more HP from 900 RPM-1500 RPM than the 600/1850 motor, with all other things being equal, the 2050 motor will accelerate faster than the 1850. The 2050 also hangs out close to peak HP quite a bit longer than the 1850. Another factor would be better shift recovery on the 2050.

Like I said, those graphs are unnatural looking to me. When then TQ nosedives, that's what looks like defueling to me. Maybe turbo manipulation. It's really telling to me that at 2100 RPM, both versions have 1425 TQ. And I'd bet if a guy measure the angle of that decline, it'd be the same, even though the 2050 starts losing TQ a few hundred RPM sooner.

The reason I mentioned overspeed b/c people smarter than me have brought it up as the reason to defuel before hitting the governor. Makes sense to me.

Maybe I'm in left field?