I know that there have been several posts on this elsewhere but it still doesn't seem like we have a definitive answer as to why the Sport AT is rated at 37 MPG highway and the Sport MT is rated at 38 MPG highway when we have clearly established that the AT is cruising at significantly lower RPMs at, say, 60 MPH. Is the L15 simply more efficient at higher RPM? Will the actual long range cruising MPG of the AT be better than the 37 rating? (and just suffering a small MPG penalty in the acceleration?) I am still on the fence on this transmission choice so this puzzles me to distraction!

 

My $0.02: The difference between the highway mpg figures between the two cars is statistically insignificant at 2.63%. I wouldn't use that as a factor in my decision as to which transmission to get. I'm such a manual sticknic I might not even consider it were the automatic as much as 10% better (not going to happen). It is an interesting topic for debate though, and gets us manual guys frothing, pointing at the figures, and shouting how much more efficient a manual is than a slushbox.

You should base your decision on how and where you drive, what you want from the car, and if you are willing to give your left leg a work-out in rush-hour traffic. Are you in Washington state, or Washington DC? I know the traffic in DC is probably some of the worst in the country.

My reasons for choosing the manual:

1. I'm insane
2. I feel more in control of the car and what I am trying to do with it.
3. I have a deep set impression, from the 70's era autos of my parents, that manuals are more efficient. I think this becomes more of a factor as you go down the horsepower ladder. Modern autos are much better, though
4. Maintenance is easier and cheaper (typically).
5. You can push-start a manual (I know, technically speaking, you can do the same on a auto, but not by yourself).
6. It's just more fun (refer to point #1) no matter what the traffic conditions.

 

I think the bigger question is why does the auto sport get 1 MPG less than the base auto - paddle shift control? - weight? aero crap added wind resistance?

 

If you read that mileage thread, it does seem like auto gets less than manual by slight.

remember that atuomatic is heavier than manual by a significant amt.
base MT/AT: 2432lb / 2514lb

sport MT/AT: 2471 / 2551lbs

 

As a resident, I can confirm this, which is why I'm going to go with the AT.

 

- Auto trannies always weigh more than their manual counterpart.
- Auto trannies always have more driveline losses than their manual counterpart. Those driveline losses translate into fewer HP and consequently, the engine must work harder to move the vehicle.

Those are the reasons why autos are worse at mileage. The reasons the auto revs lower at highway speed are likely because at the higher revs where the manual cruises the auto would get significantly worse MPG and possibly also to reduce transmission wear since autos tend to be weaker than manuals.

 

What you are saying is true, to an extent.

However, it is kind of "old school". New transmissions have torque converters which provide lockup, thereby reducing or eliminating the losses that you speak of.

 

no matter how old-school it sounds, it's still true. They have made lots of progress with the automatics over the years; adding gears, allowing for faster shifts, and reducing losses...but as of yet they have not achieved manual efficiency. And I sincerely doubt they ever will.

 

But still.
Why does the base A/T get 1 more MPG than the sport A/T. Same tranny, just the added paddle buttons.
Or are the 2 A/T's geared different? Sport geared a bit lower than the base maybe.

 

To defned the lockup thing, Fit actually locks up in every gear, where most autos would lock up in final gear.

I think for the fit, the main reason why mpg is down by 1 (which could be trivial; maybe the driver didnt' drive as nicely for that run and got a lower EPA score) is cuz it weighs more.

 

It might have something to do with the different sized tires. The 14in tires need to turn 2811 times to go a mile the 15 in tires need to turn only 2624 times. I am just making a conjecture.

Does anyone agree or does this make no sense at all? Let me know why it makes no sense.

 

That doesn't make any sense to me. All things being equal, one would expect the vehicle with the slightly larger tires to get the better mileage, because its engine would be spinning slightly slower than the other at equal speed.

I would have thought the wider tires and added weight, and slightly additional drag from the aero kit would have caused this, but the EPA ratings of the manual base and sport models are the same. To add to my confusion, I did a little ****ysis (I love typing that).

If you set the trim level, and vary the transmission only, you would expect the weight difference to be constant. It isn't. A base auto weighs 82 lbs more than a base manual, and a sport auto weighs 80 lbs more than a sport manual

If you set the transmission and vary the trim level, you also should expect a constant difference in weight. Again, it doesn't happen. The sport manual weighs 39 lbs more than the base manual, and the sport auto only weighs 37 lbs more than the base auto.

Someone who knows more about curb weights and how they are measured needs to chime in on this. I would assume the scales used have a greater degree of accuracy than +,-2lbs.

All that being said, I have no idea why the sport auto is rated one mpg less than the base for the highway. Easy solution: Get the manual...no don't, because I want one, and I don't want all of you buying them out due to limited production

 

Here is the clue - does the auto have a radiator attached? If so the designers needed to get rid of excess heat in the tranny. ie less efficient- anyone checked to see if their traanny feeds a cooler?

 

didn't some review post on here say that the sport's auto tranny has "better" or closer ratio gears that allows it to stay in VTEC power band more often (I would assume to make up for the driveline lost due to the auto tranny), and that it was more fun to drive than the wider space gears in the MT which makes you fall out of vtec on the 1-2-3 shift?

more vtec time = more fuel usage

-joe

 

A couple of points here...

175/65-14 = 2856 rev/mile
195/55-15 = 2797 rev/mile

Assuming that the weight of the wheel/tire combo is the same, the one with smaller tires would get better mileage as it requires less torque to turn them.

Go back and watch a figure skater spin around. Pull arms in, spin faster, put arms out, slow down - same thing applies here.

 

If that were the cause, then the Sport MT would be down on mpg vis-a-vis the base MT as well. Disregarding the transmission, the differences between the base and Sport models are exactly the same, so it must be something specific to the auto transmissions.

 

Here is a longshot.
Modern engine A/T combos are computer controlled right? Normally the computer cuts fuel during shifts to keep it smooth and a nice ride. At least Chrysler does this.
Comments have been made about how fast and responsive the sport A/T is. Maybe Honda set the computer to not cut fuel during shifts for performance reasons.

 

the km/l reading on the dashboard always shows 7.2-8.0 in stop and go conditons ie. lots of short trips.. is this value ok? and will it defer to the conventional calculated value.. i just bought the car.... mines a 1.3 Idsi CVT trans