2021 Cummins 1075 lbft peak torque at 1356 rpm

4x4ord wrote:
I missed a scenario. I think towing into the wind at 55 mph would take us about 150 Kw. I’d be running in 5th @ 1528 rpm so 937 Nm. That should put me about 200 g/kwhr and 5.9 mpg.

You’d run in 8th @ 1687 and be putting out 849 Nm. You should be close to the middle of the sweet spot say 192 g/kwhr ..... 6.1 mpg!

I used a target of 201 hp and picked the gear that falls into the dark blue land on the BSFC.

1st up, the 10 speed:



Now the 6 speed Aisin:



Here's the fun part, with the 10 spd: 1694rpm @ 623 lbft (845 Nm) falls right in the middle of the dark blue region.

With the 6 spd, 1535rpm @ 691 lbft (936 Nm) just falls outside by the old map. So with the 2019 engine, we theoretically lose about 5% fuel efficiency. But I wonder if coolant temp / egt is better at the 10 spd's higher rpm.