How Much More Efficient Is The Standard Output Above The High Output CTD?

[Goose55]

I've gotten some answers to this question before here in the forum, but so that it is clear, I want to run this buy everyone again: The latest Cummins 6.7 has a High output (HO) and a standard output (SO). The SO has a compression ration of 19:1, and the HO something like what is it, 16:1?

Now, before you answer this, you have to either own a 5th Gen SO, or know someone that does. All others please refrain.

What is the real difference in fuel economy between the HO & SO CTDs?

 

[06 Dodge]

FYI the 2019 up truck's & engines are not 5th Gen more like 4.5 Gen... Its my understanding the SO like what I have in my 22 is much better on fuel then the HO, this is based on talking to a few HO owners, its around 2-3 mpg diff between the 2 engines...

 

[nlambert182]

I've owned both a 6.7 HO and a 6.7 SO and saw similar fuel mileage in both. I really didn't notice much of a difference in either one.

 

[Goose55]

I've owned both a 6.7 HO and a 6.7 SO and saw similar fuel mileage in both. I really didn't notice much of a difference in either one.

On that SO I assume you had the 3.73 gears, and the HO 4.10?

 

[nlambert182]

Other way around, actually.... 3.73s on the HO and 4.10s on the SO.

 

[Goose55]

Other way around, actually.... 3.73s on the HO and 4.10s on the SO.

My '19 HO came with 4.10 and I just ordered a '23 SO with 3.73.

 

[Choupique]

You're excluding a lot of qualified people with your caveat

before you answer this, you have to either own a 5th Gen SO, or know someone that does. All others please refrain.

 

[RamGuy110]

My 21' dually was a SO with 4.10s. It got noticeably worse mileage than the dually with the SO and 3.73s that I rented from Enterprise prior to buying it.