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Why are the automatic transmissions geared higher (i.e. lower RPMs at highway speeds) than the manual transmissions.
I've attached some graphs showing the gearing of 2010 Honda Fits (5 speed auto vs. 5 speed manual). The automatics achieve better highway fuel mileage because the manual transmission fits rev a lot higher in 5th gear.
Does anyone understand why the manual transmissions rev higher at highway speeds? Does it have something to do with the automatic transmission putting out more torque based on a fluid coupling vs. a direct connection between the transaxle and the engine?
Honestly I think they just don't want you to feel like you have to downshift to pass.
I agree with you, if the manual was geared like the auto, you'd have to downshift to pass and to climb hills on the freeway. The car would feel gutless an unresponsive in 5th gear.
But it's such a stupid reason to sacrifice overall highway fuel economy in order to avoid the odd downshift on the highway. I'm pretty sure anyone that drives the manual version wouldn't mind the odd downshift if it gave you an extra 3-5 mpg.
I drive from Phoenix to Flagstaff, going from 1300' altitude to 7000' altitude. Have 2013 Fit base with 5 speed stick. I do have to downshift at certain places on the road, due to passing slow traffic. Usually just go to 4th and then back to 5th when I get back to speed. Don't mind the downshifting and am surprised how many cars I pass going up the hill. I have gotten over 40 MPG on many occasions, so not worried about MPG. I do know a stick is faster off the line than an automatic & I prefer that, since all I have is 117 HP.
Isn't there a 6 speed tranny? I wish i had it. I agree, the rpm is high in the highway.
The GK Fit's have a 6 speed manual, but I believe the gear ratios are the same spread as the 5 speed. Basically, they are closer together for smoother acceleration , rather than making 6th an overdrive/highway gear...
We just need a 7th gear for overdrive. I think honda doesnt trust that people will downshift with OD gearing, and will instead lug the engine at WOT and cause undue stress.. Just a hunch...
