Automatics getting better MPG than manuals?

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11,284
Location
Spring HIll
2006 Honda Civic and Kia Rio! Both garner higher MPG figures with the auto-shifters compared to the stick shifts, especially on the highway. I can see a CVT trans offering this ability, but a geared Auto trans? It seems such a rare thing to see this. What's their secret??
 

Al

Messages
19,225
Location
Elizabethtown, Pa
I believe its easier to drive for higher milage with any modern 4 speed auto. You can use less accelerator pedal and keep it at say 10-15% Throttle Position through the gears. The key is to get it to have the torque converter lock up as quickly as possible. My Sentra 2L is rated at 24 mpg city(manual) and 23 (automatic). I can easily get over 28 city in my auto.
 
Messages
47,765
Location
Duvall WA - Pacific NW USA
I have seen an improvement with 5 speed autos with taller final drive and better lock-up. This combo seems "more inteligent" than the average bear at extracting the best MPG. Sad but true, and hard for me to swallow as a die hard MT guy.
 
Messages
142
Location
Atlanta
quote:
Sad but true, and hard for me to swallow as a die hard MT guy.
Even harder to swallow with the VAG DSG, out accelerates MT as well as gets better MPG.
 
Messages
101
Location
Depew NY
Get a sorter 5th gear then? Im thingking of putting an AWD 5th gear into my FWD eclipse, since it has smaller final ratio. I only use 1st through 4th gear in the city. Im gonna look into an even shorter 5th gear beacuse when im going 75mph on highway im in the 3700 rpm range
 
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1,910
Location
Vista, CA
I think you are talking about auto's performing better in EPA test sequences. There may not be a direct connection between those tests and real life. I think most drivers that works at, just a little, can easly beat an automatic. If you cannot, maybe you should avoid a standard transmission. Also if you can't be bothered paying attention when you drive, or have too many phone calls, then an automatic is the one to pick. Driving for a lot of people has become a moving office with entertainment and communications. So, who cars about mileage, the phone is ringing.
 
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10,830
Location
Nokesville, VA
quote:
You can use less accelerator pedal and keep it at say 10-15% Throttle Position through the gears.
Gasoline engines are more efficient at higher throttle openings (and, therefore, higher load) so this is not the most efficient way to accelerate. In a manual you can accelerate at 80% throttle and shift at 2000RPM AND skip gears. Try that with any automatic.
 
Messages
10,830
Location
Nokesville, VA
The engine control computer could (with the right software) be smarter than an accelerator pump on a carburetor. Of course, I also recall that some automakers had a little bit of trouble getting misfire detection to operate reliably with a manual.
 
Messages
1,013
Location
wisconsin
I have a 2005 Altima 3.5 SE with a 5-speed manual it is rated at 21 city and 27 highway. The same car with an automatic transmission is rated 20 city and 30 highway. The car turns about 2,800 rpms on the highway which I think is high for a newer V-6 vehicle. I don't know what the highway rpms are on the automatic is but I would think it is much lower.
 
Messages
1,357
Location
California, USA
Most BMW's have a MPG meter in the tach (NOT a vacuum gauge), making it easy to drive a stick for fuel economy. As far as throttle plate pumping losses are concerned, the latest engines have variable-lift valves and no throttle plate ("Valvetronic").
 
Messages
1
Location
ohio
I was told that the sudden closeing and opening of the thottle during the shifting plays havic with the pollution control systems. Automatics have a more consistent thottle position
 
Messages
1,175
Location
Long Beach, CA
Automatics tend to upshift far earlier than I do when I drive a manual. This may account for the better MPG: low rpm/higher gear + wider throttle opening = more efficiency
 
Messages
545
I had always been a "..stick man.." till the past several years. My wife was driving a Sentra 1.6L w/auto that gets 32MPG around town and 36+ on long trips. She is now driving a newer Sentra 1.8L with auto that is doing almost exactly the same. I'm now driving the 1.6L and I'm very happy with its performance and the great economy.
 
Messages
23,591
quote:
Even harder to swallow with the VAG DSG, out accelerates MT as well as gets better MPG.
While I'm a hardcore MT guy, the DSG is great. That's the only kind of auto I'd drive -- but I'd shift it manually anyway. Unfortunately, I doubt that anybody can fix the DSG if it breaks. I also doubt that the cost to fix it is anywhere near reasonable (My '96 A4's MT costs about 9 grand to replace, so how much is a new DSG? 15k?). But yes, a 2-door A3 quattro with DSG would be sweet...
 
Messages
4,478
Location
Southern California
quote:
Originally posted by steveh: I have a 2005 Altima 3.5 SE with a 5-speed manual it is rated at 21 city and 27 highway. The same car with an automatic transmission is rated 20 city and 30 highway. The car turns about 2,800 rpms on the highway... I don't know what the highway rpms are on the automatic is but I would think it is much lower.
Comparing apples and oranges, perhaps, but my '03 Sonata 2.7L V6 with AT - no clever variable valve timing hardware available for that year on that motor - the engine speed at 75 mph in 4th gear overdrive with torque converter lockup engaged is exactly 2,500 rpm according the tach. EPA fuel economy rating for this car was listed as 19/27 on the MSRP sticker. I'm consistently getting 22+/- mpg city, and 32+ mpg at the above highway speed.
 

Kestas

Staff member
Messages
13,942
Location
The Motor City
On the other hand, automatics can shift faster than any manual, plus they don't shoot a rich mixture of fuel through the engine with each shift. That's why automakers tend to favor automatics... it makes the EPA happy.
 
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