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MPG: Auto tranmission vs. Manual a fair comparison?

Is it a fair comparison to say manuals and auto transmission get the same MPG in newer cars? The 2012 Toyota Corolla has a 132 HP engine and this same engine is paired with either an auto or manual transmission. According to “Consumer’s Reports Guide to New Cars” the MPG ratings are identical, manual or auto. But the 0-60 mph acceleration times are definitely not the same. The manual has a 0-60 time of about 9 seconds, while the auto is 9.9 seconds.

To me, 9.9 seconds is only borderline acceptable for acceleration. 9 seconds makes a car far more drivable, especially accelerating to traffic speed on freeway on-ramps.

While the engines are rated the same HP, the actual power delievered to the wheels is not the same. So is it fair to say the MPG is the same, when the effective power to the wheels takes a big hit with the automatic transmission? I mean if the Corolla manual had a 100 HP engine it could probably hit 0-60 in 10 seconds. And then it would get better MPG.

What do you think?

Probaly not as bad as you think,some people cant drive a manual as well as they believe dispite thier fantasies.These testers are professionals who run the devil out of the cars they test and are the axle ratios identical? Its generally accepted now that good automatics are about fuel efficient as manuals now.Test drive yourself then decide,One of the big reasons to get a manual is the usual up front savings on MRSP-Kevin

mpg, and 0-60 mph are not the same benchmarks. MPG is most impacted by the final drive ratio, which may or may not be the same for the auto vs manual trans in the same car.

In real life it boils down to driver preference. A manual vs auto is the choice if the driver wants more control and less maintenance costs over the life of the car go manual, if you want convienience then go auto.

In modern cars auto transmissions are just as efficent as manual, just more complicated and more money to maintain and replace down the road.

What is the actual 0 to 60 time on your current daily driver?

The acceleration/mpg negative of automatics are far less than they used to be, as you’ve shown. In addition, the latest drive-by-wire throttle/fuel injection/engine management systems work best when they can manage the transmission shifts, too. So manuals will continue their decline…

I believe that your suspicions are correct in that a manual is more efficient at transmitting engine power to the drive wheels. Vehicle mfrs provide the EPA with fuel mileage numbers and the EPA only spot checks these. A vehicle mfr can post any number less than what is possible without penalty but not more so the automatic vs manual fuel mileage numbers can be inverted. The reason for doing this is a marketing one in that an automatic transmission option in a new vehicle is a better profit source. It has been posted here on Car Talk that Consumer Reports confirms that manuals deliver better fuel mileage than automatics in spite of EPA numbers to the contrary. Note too that fuel mileage leaders such as a Chevrolet Cobalt XFE (37 mpg) and a Chevrolet Cruze ECO (42 mpg) have manual transmissions. If you keep your car to the end, a manual will prove again that it is less expensive to drive when your choice of an automatic transmission or a manual transmission clutch need replacement. Manual transmission gearboxes can typically never fail when driven with normal caution.

Comparing my 03 Scion xB w/ a 5spd MT and mom’s 08 Honda Fit w/ a 5spd AT, both have similar engine size and body style, there’s virtually no fuel efficiency difference between those 2 cars when cruising on the highway. Both manage around high 30s.

However, there’s a noticeable difference on surface street and commuting. The MT car never dip below 30 and the AT car stays at high 20s. The MT car doesn’t have slipping torque converter that doesn’t lock at low speed; it doesn’t have a computer blocking top gear when the car can do just fine in it; it never give more power than asked for unexpectedly so I could meter out power more precisely and avoid braking even on surface street.

Given the OP’s screenname, an MT may not be the best financial choice if it’ll be asked to frequent the city of hills. That’s where the clutch is likely to see abuse even in the best of hands. Any mileage gain may not cover sooner than normal clutch jobs.

A manual should do a shade better on mileage as compared to an automatic but the differences are not as glaring as they once were. That’s assuming things are good mechanically in both versions.

You can actually spot that .9 of a second difference from one to the other?

In these discussions the conversation tends to run seamlessly between economy, efficiency and performance. They are related but fundamentally different things. Trying to relate 0-60 performance to a MPG estimate is IMO not very useful. Mileage rating calculations are based on a predicative model that assumes a certain number of stops, starts, average acceleration and speed. The manufacturers know the drill and have a whole host of things they can to tweak the numbers. Hence the disclaimer: “your mileage may vary”. Automatic transmissions with torque converters aren’t as efficient as manual transmissions. Lock-up does a lot to even things out. Plus the manufacturers can program the shift pattern to favor the mileage calculation. The latest development, the fully automatic double clutch transmission will erase most of the differences. Yes, theoretically a skilled and consistent driver can get better mileage with a manual transmission, but that isn’t the reason most people choose a manual. It’s hard to better but more fun to do worse.

I predict that in the not too distant future, automatics will be able to give better mileage than a manual under any condition.  It really does not have that far to come and there are still lots of places where computers can offer improvements.

You’ve raised two different issues here.

As for fuel economy differences between automatics and manuals, automatics have steadily improved over time to the point where they’re pretty close to manuals. I’m not surprised to see the same number in your case.

As for the power and acceleration, just because one car is somewhat better in a 0-to-60 time, that doesn’t necessarily mean that it will merge better. You really want to look at the 30-to-50 and 50-to-70 times often found in car magazine reviews, which could put the cars in the other order. Regardless, any car with a 0-to-60 time over 9 seconds is a slow car that will need to be driven with that fact in mind (probably ruling out most passing on two-lane roads, for example).

Here is a possible reason why an automatic will have a difficult time of achieving power transmission efficiency over a manual. An automatic and a manual both have gears, bearings and shafts that are operating with some resistance to turning in oil. In addition to that, an automatic has an oil pump that a manual does not have.

The 2012 Corolla has almost identical mileage for both transmission configurations. The city/highway/average for the manual is 27/34/30 while the automatic is 26/34/29. The EPA mileage tests are designed to allow you to make a comparison between any car when you want to buy one. Your mileage may vary, but it will change in the same way for anything you buy. If the difference in 0 to 60 time is important for you, then you will get very slightly better mileage with the manual. I didn’t look it up, but the manual transmission is probably at least $1000 less than the automatic, too.

Many vehicles will get BETTER gas mileage with an automatic then with the manual.

Wonder how MPGs would differ between manual, automatic and CVT given the same vehicle.
Also, manuals are now actually starting to lag behind automatics in terms of gear numbers. I know Porsche is coming out with a 7 speed stick and Mercedes, I think, has an 8 or 9 speed automatic.

If .9 of a second makes you late, see if you can leave .9 seconds earlier. And make sure you are alone in the car, that might make it a little faster.

I agree with Uncle and feel that in real life, there is little difference in acceleration between an automatic and a manual for most drivers. In situations where acceleration to the max is needed, autos are definitely more dependable performers. You have to stay on top of your game, every time to make a manual perform on par or better then an auto. That ain’t gonna happen at the end of the day after a hard day at work.

There are real good reasons why emergency vehicals including police cruisers are for the most part, automatics. I feel it has as much to do with dependable performance as economy.

I have been driving for eh, 64 years and I have always prefered an automatic over a manual. I have an automatic now that shifts so smoothly that it is very hard to notice. It only has 55k on it now so time will tell how good it is.

Well I always considered a automatic transmission an upgrade in my latter years especially.reading the Dodge Ram site I noticed that the Automatic equipped heavy duty Ram,with the Cummins Diesel was rated at 800 lbs ft of torque,while the engine in the manual equipped truck was derated to just a bit over 610 lbs ft of torque,if I read the info right. The point is automatic transmissions are darn good now,heck most lawnmowers and farm tractors are hydrostatic now,most automatics will last the life of the car now with proper maintenence.Can you imagine running a D-8 Caterpillar all day with a manual transmission,the little fuel efficency you give up is well worth it,( besides its hard to text,comb your hair,drink your coffee,while shifting gears)-Kevin

@RodKnox, my current daily driver, a manual Toyota Corolla, it spec’d a 0-60 of 9.3 seconds I think, as a new car. The auto xmission version was about 12 seconds as I recall. When I test drove the automatic at the time, it was too slow to even consider. But the manual is pretty zippy, both from 0-60, and especially where I noticed it differed from the automatic, from 0-30, so the manual version is fun as a drive-about-town car too.