That's fine I know a 13.5 l harder we run a 9770 and and a 9870, but the 770 I see is close to 400 hp now not 360hp like the 9770A 13.5L is going to consume significantly more fuel than a 9.0, no two ways about it. Everything else is entirely dependent on header size, ground speed, crop type, etc. I'm sorry I don't have hard numbers for you to compare. I'm simply repeating what my customers have reported to me.
Thanks sounds like a no Brainer to look for a 770.Ran a s680 with beside s670 (2014 -391 rated horespower 449 with boost) same chopper and spreader,in 112 to 122 bushel very heavy lodged,lots of straw swathed barley.Machines going same speed all day going faster just put barley out the back,neither machine stopped all day,filled with fuel both machines in the morning till fuel nozzle clicked,filled again in the evening till nozzle clicked s680 used 95 liters more and both machines harvested same amount of acers.That was in 2020 when crops were excellent here.