RPM Mileage questions on a honda accord(07)

[Lithium381]

I've been in both the 5spd auto and the 5spd stick version of the '07 accord.....they both claim to get 34mpg on the highway. I noticed, however, that the automatic is running around 2krpm at 70mph and the stick is at 2.7krpm at the same speed. How is it possible that they are both rated at the same mpg when it seems logical that the auto would get better freeway mileage since it's going at a significantly slower engine speed? Any thoughts?

 

[postmortemIA]

are you running both of them in their last, overdrive gear?

EDIT. Maybe they have different gear ratios on last gear as well.

 

[Lithium381]

yes, both were in the final gear(5th) They obviously have different gear ratios, but what i'm asking is how, even with different ratios, they both offer the same mileage at the same speed(crusing on the highway)

 

[Tommouse]

The torque converter being less efficient than its clutch and flywheel opponent? That's my guess, it's the same way with my car. 5spd at 3k @70mph and 2.5k @ 70mph with the tiptronic.

 

[jagec]

Well, a modern automatic *should* lock up the torque converter on the highway. It's still got a lot of weight to make up for, though, and drivetrain loss is almost always higher than a manual.

Not to mention that sometimes the engine is actually tuned differently, depending on which transmission is installed.