Automatic vs. Manual transmission

It's been well known a manual transmission obtains better fuel mileage than
an automatic. My sister is preparing to purchase a Ford Fiesta and wants a
manual, mainly for the fuel savings. The sales guy indicated the new
transmissions (more so the 6 speed auto in the Fiesta) are better and more
fuel efficient than manuals. Anyone know if this is true?
Reply to
SBH
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Yep, The computer know how to shift the trans for economy better than you do. The only reason that older autos were worse than a stick was due to the slippage of the converter and the lack of close gearing. New trans have lock up, better gearing, better overall gear ratios and the computer controls make them work much better than a stick.
Reply to
Steve W.
lots of people know the answer to this. you could too if you could be bothered to look up the numbers on the manufacturer's website.
you'd be better off asking the question "why" - if you don't want a "rtfm" answer.
Reply to
jim beam
But for small cars with small engines an MT will probably still be more responsive than an AT programmed for fuel economy.
Reply to
Brent
In many cases, the automatic is at least as economical as, or sometimes better than, the manual. The difference is not worth the worry. And dats the truff, babe ruff.
Reply to
hls
Silly me, why didn't I think of that....? Oh wait, I did, but that doesn't erase my skepticism about manufacture mileage posting. It's similar to the little guy enhancing the size of his johnson because it really isn't. Therefore, I thought I'd bother myself twice and ask in here as well. You know what they say about assumptions.
Reply to
SBH
The new Ford 6 speed auto has no torque converter. It uses a computer applied clutch to start and shifts between two clutch driven gear trains that change the ratios- one for odd, one for even gears. I wonder how the clutch life will be.
Reply to
Mr.E
According to
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, the "regular" automatic Fiesta is rated 29 city / 38 highway. The "regular" manual Fiesta is rated 28 city, 37 highway. The SFE Fiesta, which has the automatic, is rated 29 city, 40 highway. Interestingly, both the regular Fiesta automatic and the SFE Fiesta automatic have a combined rating of 33. The regular manual Fiesta has a combined rating of 32.
So, at leat in the government mandated tests, the automatic does get better fuel economy than the manual. The fueleconomy.gov website allows individuals to post fuel economy estimates. The individual estimates for the manual transmission model Fiestas are higher that for the regualr or SFE automatic versions (36.7 for the manual, 34.7 for the regualr automatic, 32.5 for the SFE automatic). These are "personal" estimates, so take them with a grain of salt.
Consumer reports tested both manual and an automatic versions of the Fiesta. In the CR testing the overall mileage for the manual was 32 vs 33 for the automatic. The manual got 39 mpg on the CR 150 mile trip. The automatic got 41 on the 150 mile trip. For CR the manual averaged 23 city, 42 highway. The automatic averaged 22 city and 45 highway.
Be aware that the Fiesta automatic is not a traditional automatic. It is a sort of computer shifted manual transmission. It is a dual clutch transmission and unlike traditional automatic transmissions, it does not have a torque converter. See
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I have a 2011 Fiesta with an automatic. So far in my normal sort of driving I am averaging just short of 36 mpg. I don't get a lot better on a long trip (maybe 38 or so) but then I don't get much worse around town. I bought a regular automatic Fiesta (not the SFE). The SFE model costs about $600 more and although it has a higher highway rating (40 vs 38), the in town and combined ratings are the same as the regular Fiesta. According to the Ford salesman (not exactly an expert in my opinion) the SFE has additional areodynamic features that allow it to achieve the higher highway ratings. I doubt this (I didn't see any dramatic differences). I think it had more to do with the tires (the SFE has different tires) and possibly the transmission shift programming. I drove both and didn't really see much different in performance between the two.
Ed
Reply to
C. E. White

I imagine it will be very good. It doesn't use the sort of clutches used by a manual. It uses stacked clutch packs that are hydraulically activated. I have a farm tractor with this sort of transmission. After 20 years of hard use it is still just fine. And remember "traditional" automatics also include clutches that are activated hydraulically. No reason to think the clutches in the Fiesta "automatic" will be more failure prone than those.
Ed
Reply to
C. E. White
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In Europe, Ford currently offers a PowerShift transmission in the Ford Focus. This PowerShift uses a twin wet-clutch system to handle the higher torque levels of the 2.0-liter TDCI engine available in the Focus.
In North America, a dry-clutch derivative of Ford?s PowerShift transmission will be used for added efficiency and durability. A dry clutch transmits power and torque through manual transmission clutch facings, while most automatic transmissions utilize wet clutch plates submerged in oil. As a result, the dry-clutch PowerShift transmission does not require an oil pump or torque converter, providing superior mechanical efficiency.
?A dry clutch is a real sweet spot for lighter vehicle applications,? said Piero Aversa, manager, Ford Automatic Transmission Engineering. ?PowerShift is more efficient, it saves weight, is more durable, more efficient and the unit is sealed for life, requiring no regular maintenance.?
PowerShift, unlike conventional automatic transmissions, does not need the heavier torque converter or planetary gears. In addition, the dry-clutch derivative eliminates the need for the weighty pumps, hydraulic fluids, cooling lines and external coolers that wet clutch transmissions require. As a result, the dry-clutch PowerShift transmission can weigh nearly 30 pounds less than, for example, the four-speed automatic transmission featured on today?s Ford Focus.
Reply to
Mr.E
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Thanks very interesting...but what operates the dry clutches? The article says "electro-mechanical"...so does this mean a solenoid(s)?
Ed
Reply to
C. E. White
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No clue Ed- I ran across lots of info when researching 2011/2012 cars to replace a 94 Corolla that a tree fell on. Still not totally decided..
Reply to
Mr.E
Well so far my experiences with the Fiesta automatic have been positive. It is not quite as smooth as the AW 6 speed in my old Fusion, but better than the AW automatic in my SO's RAV4. The only oddity I've noticed is the hill holder "feature." Works OK, but feels "different" than a traditional automatic. But it is much better than starting up a steep hill with a traditional manual.
Ed
Reply to
C. E. White
It depends entirely on who is driving. Some of the computer controlled automatic systems are very, very good and probably better than the average driver.
However, when those systems break, nobody really knows how to repair them, whereas rebuilding a manual (even a transaxle) is something you can do in the backyard. --scott
Reply to
Scott Dorsey
Who knows if the manufacturers are telling the truth about the fuel savings. I haven't met one person that gets the mileage that was posted on the sticker from the factory. Believe them if you want.
Reply to
anniejrs
anyone saying this stuff is hard to repair is the same kind of luddite that said that about fuel injection 30 years ago. now we laugh at injection luddites, not only because injection systems are simpler to repair, but because they're much more reliable.
that's not true. look at one of these 6-speed dual clutch systems - apart from the electronic control module [which i hope you don't think is any less reliable than an injection computer], it's no more complicated than a traditional stick. /way/ simpler than a traditional auto with its hydraulic analog computer, pumps on input and output, multiple actuators and multiple clutches. if you can't handle just two clutches and a few electronic solenoids, you've got other problems.
Reply to
jim beam
I did a short review of those just now. I don,t know what the fuss is about. In my 2001 cavalier I have got 34 mpg doing average of 65 mph up and down hills. On the flat I should get minimum of 36 mpg doing 55mph, Mabe more. My chevy has a 4 speed, but hear a 5th noise, maybe lockup.
Greg
Reply to
g

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