I know that this is not a direct comparison as it involves two different models, two different cars, and two different driving conditions, but I find it interesting. My Mom drives 90% Interstate with her 2011 Fit Sport Auto and is averaging 32 mpg lifetime. We drive 50/50 Interstate/City with our 2008 Fit Sport Manual and are averaging around 35 mpg lifetime.

Her car is not lifeless or that boring to drive. It's just not as much fun. What shocks me is her poor mileage relative to ours. I suggested the auto because of her extreme bias toward Interstate driving, but I really thought she'd get better mileage. Her average is in line with the worst tank we've had in almost 4 years of ownership and she's never had a fill up that was as good as our average.

We take frequent 9 and 10 hour trips in our Fit MT that are 100% Interstate. On those trips we get 35 every tank, every time.

 

Comparing 2 cars is a diificult situation; thats why the feds run the 'standard' mpg trials on a computer controlled driving route rather than real drivers.
If you want a good comparison trade vehicles for a tank worth.

PS paddle-shifting is just as accurate and quicker than manual shifting. If Sebastion uses a paddle-shift what makes you think clutches and pedals are better?

 

Wow, this thread is funny. The difference is so small that its really not even worth arguing over.

Carry on tho, I'm bored at work and need more laughs.

 

well then...

I think it's the soulless comment that smarts the most. As if a car you must manually row has more soul than a car that shifts itself. This seems counter-intuitive.

 

Not that I care about this thread argument because it was started by a troll, but I would consider handmade bread as something that has more soul than factory made Wonder bread. It's the human aspect that gives things soul.

 

Ahhh, so my pedal car from when I was 4 had the most soul. gotcha.

The Japanese ghosts in my machine are very happy doing the work of shifting for me. Consider the design hours, both hardware and software. My Fit ooozes soul. Or is that transmission fluid?

 

Interesting. My '09 m/t got a max of 38 mpg at 75 mph. My '10 A/T gets 40-41...same roads same speeds. Consistently. Guess there is a big difference in the roads. Ours is dead flat, 100 mile straights. The paddles are fun, but rarely use them in the Fit or my Camaro. Awkward when turning.

 

My manual did better in town, worse on interstate; I blamed it on the mucher rpm for the manual on the interstzte running 75 steady with either.
Stands to reasob that the more times you fill the cylinders the more gas is consumed.

 

no no, higher rpms= higher mpg, solbrothers said the manual does better in every way and RPM's on the freeway don't matter. You could actually stay in 3rd going 75 with the manual and still do better.

 

I agree completely about the two different vehicles/drivers making it an unreliable comparison. I guess what it shows more than anything is that some people get better mileage than others and it may not have anything to do with the auto/manual. My best guess is that my Mom leaves her car running while she works her 8 hour shift

As for the paddle shifter vs. my powershifting...even though I have drag raced for the past 23 years, I can't outshift a fast shifting auto. However, the fact that a manual Fit has roughly 10 more wheel horsepower due to the inefficiency of the torque converter design. Check out any magazine test and you will see that the auto Fit is roughly 1 second slower in the quarter mile. For those of you non-drag racers, that is a HUGE difference. That means an auto Fit would be roughly 10 car lengths behind the manual. 10 car lengths means they would not even be able to read the license plate of the manual car.

As I keep saying, does this matter in the real world, probably not. Drive whichever makes you happy.

 

Hey, since Solbrothers knows everything, how about leaving it in 2nd and run 7 grand on the freeway. Mileage would be phenomenal.

 

In his defense, higher rpm doesn't mean more fuel necessarily either. Fuel usage can more or less be derived with a sliding scale based on throttle position and rpm.

So, if you are at 50% throttle and 2,000 rpm that will be roughly the same fuel usage as 25% throttle and 4,000 rpm. That is why gearing is so important. If the car turns too little rpm on the Interstate, the motor will be lugging and more throttle will be required to maintain speed.

I do realize this is a way over simplified example because there are many more factors, but my point is that rpm is not the only variable in determining fuel usage. Ideally you want to go down the road with the least throttle and rpm required to maintiain speed.

 

I know, a lot is involved. But the fact is, the A/T for a lot of people, consistently gets better mileage than the M/T on the highway. In town, the opposite.

 

I'm consistently around 34-35 mpg in metro Atlanta rush hour. Another driver, with same route, could be coming in at 31-32 mpg.

Every right foot is different.

 

IDC and RPM will be the main factors in fuel economy. For GDs.. These are directly affected by IAT, MAP, Baro, ECT and Fuel Quality.

GEs have a MAF, so IAT, ECT, Baro and Fuel quality still apply.

Basically it comes down to the "Load" calculation, which is basically cylinder pressure, and air mass in terms of g/cyl/rpm. The greater the knock threshold of the fuel, the leaner it can run and the more timing can be used, which in turn results in more power out of a smaller requisite fuel mass.

Even with a lock up converter, the MT will still get greater fuel economy, except above the threshold (somewhere in the 75mph range) where the marginally taller gearing will help a bit.

There is more parasitic loss from mechanical and fluid friction, and from greater chassis mass, rotating drivetrain mass, and myriad other losses associated with the internals of the auto trans.

Above 75mph it can go either way dependent on a wide range of factors, but there is the potential for marginal gains with the ATs gearing and the converter locked. Below that in the vast majority of situations the MT has the upper hand.

So if you commute say 50 miles eachway on the highway in a state where the speed limit is greater than 65, there may be an advantage. Outside of that, not so much. Even then this is subject to driver/operations/maintainence habits, environmental conditions, topography etc.

For those (not picking out anyone in particular) trying to boil down fuel economy to something clean cut.. stop it. Its silly and an annoying round about conversation.

If you have an AT and feel the need to "defend" its sportiness and economy.. that great, but it still dulls the car down a good deal. There is more weight, there is greater drive train loss and you don't have full control.

An MT may require a clutch/TOB/Slave chang, but that is still easier/cheaper than replacing an entire AT in terms of labor & parts.

You got the AT for convenience, thats fine. Don't make it out to be something its not.

There are more than a few members logging fuel economy, the vast majority posting big numbers are MT, there is no escaping that fact.

If you need a pat on the back, perhaps the internet was not the best place to go.

 

I can see where 50 miles will make a difference where say 20 miles does not. And where 65mph makes a difference (or is it 75 MPH?). And the friction losses through the transmission make a difference and through the engine do not.

And of course the EPA estimates have no basis in reality at all especially since their highway estimates are carried out under 60MPH (avg speed 48.3), and your average driver can outsmart the engineers at Honda through soulful shifting.

Thanks for clarifying.

 

I read your entire post all seriously, and then read this

That is sig worthy.

 

Wondering what you ended up getting and hope your still around. It is a unique crowd, to say the least ;-)

- - - - - - - - - - - - - - - - - -

It continues to amaze me that folks come here looking for info and end up being totally ignored and barraged with mindless jibberjabber.

K_C_

 

Lord save a duck. Higher rpm means filling the cylinders more often; if you compare downhill with a manual with uphill with an automatic the MT will get better mpg but not on a computer programmed test. I've done it numerous times. The difference between Fit MT and AT rpm at 60 mph is too much to overcome the advantage of the AT.
Solbrothers? thats your textbook?
And sure, the AT can be loaded with really heavy tires by comparison but thats not a comparison; weight, tires, etc have to be equal.
Here's a new one for you. One of my customers bought a new Sonata and couldn't wait to show he gets as good mpg with his 3500 lb AT as my Fit, 28-30 mpg.
Course with a 6 speed transmission his rpm at 60 is about 1600 rpm while mt Fit is doing about 2400 rpm.He's refilling his 2.4 liters abut 800 times a minute while my Fuit is filling my 1.5 liters 1200 times a minute. You think there's much difference in the fuel injected per cylinder? Because the Sonata
Lets see, thats 1920 liters vs 1800 liters. If it weren't for the extra weight the Sonata would probably beat the Fit because the added torque from 2.4 liters would let the Sonata carry much less gearing than the Fit's 1.5.Its not always true that less displacement means better mpg; its how hard the engine has to work.

 

Its too bad this topic got hijacked from the first response the OP got.

The only real issue for highway and the MT Fit is if the extra noise/higher RPM of the engine running at highway speeds gets to be bothersome. Just forget all this talk about MPG because when its all said and done, its going to be close enough you won't even notice the monetary differences between the two. The noise, that might get old quick for some folks, but at least the 2012s should be better insulated.