Are automatics really more efficient than sticks?

[fdcg27]

There is a lot of information out there in which it appears that some form of automatic transmission will deliver better fuel economy than can a manual in the same car.
The most direct comparison that I've had involved two four door Accords of the same generation, a '99 five speed and an automatic '02.
The '99 was consistently about 10% more economical in similar actual use.
I suspect that an intelligently driven stick will always be more economical in actual use than will the same car with some sort of automatic, including the increasingly ubiquitous CVT.
This may be a moot point, since almost nobody buys sticks these days.
Maybe they should.
The driving entertainment value is undeniable for those who drive sticks and the fuel economy savings realized in the real world are icing on the cake.
What do all of you think?

 

[turtlevette]

That's the thing manuals are entertaining and when driven that way are not efficient.

Autos have lock up converters so its about a wash. With lots of idling in traffic I wonder if unloaded idling uses less fuel than loading the torque converter.

 

[demarpaint]

I think driving conditions play a big part. In heavy stop and go traffic where getting into 3rd gear is a rarity I'd give the auto the advantage.

 

[WillsYoda]

It depends on the car. Some get more efficient with manual, others with automatic. It used to be that manuals were usually much more efficient, but that is not longer the case.

 

[BMWTurboDzl]

Today the A/T is vastly more efficient than a manual. We can start with the number of gears. Today the A/T can typically be had with 7 or more forward gears unlike the typical 5-6 found in most manuals.

Also the A/T today can deliver full lockup on 1 or 2nd gear.

 

[Reggaemon]

It seems in many cars the final gear ratio is lower,like 4.10, for the car
with the manual transmission. While the automatic is higher, like 3.73.
The automatic is using less rpm at cruising speeds.

 

[HangFire]

Originally Posted By: BMWTurboDzl
Today the A/T is vastly more efficient than a manual. We can start with the number of gears. Today the A/T can typically be had with 7 or more forward gears unlike the typical 5-6 found in most manuals.

Also the A/T today can deliver full lockup on 1 or 2nd gear.


I really don't think there's enough room for "vastly". The gap has closed, that's for sure.

Take a look at the number of gears in these new many-speed automatics. Some speeds are only used in downshifts, others only used in the upshift cycle. The result might be more optimal for emissions and avoiding preignition than fuel economy.

 

[CKN]

Doesn't matter. Manual transmissions are going the way of the dinosaur......

 

[ecotourist]

Originally Posted By: Reggaemon
It seems in many cars the final gear ratio is lower,like 4.10, for the car
with the manual transmission. While the automatic is higher, like 3.73.
The automatic is using less rpm at cruising speeds.

I think this is a large part of any observed difference. The automaker assumes the owner of a manual wants to see performance so they put in a numerically higher final drive.

Aside from mileage, the other thing to consider is the total cost over the life of the vehicle. Manual transmissions are rarely replaced. Clutches are replaced in some vehicles but they're not that expensive. Automatics, a bit more frequently and are pretty costly. Worse than that, the automatic typically goes when the vehicle is older which often results in a one-way trip to the wrecker.

Any of you who follow Bring a Trailer know that manual transmissions in older vehicles are generally considered a positive feature. I'm a drive 'em 'till they drop kind of guy so a long trouble free life is important to me.

 

[Vuflanovsky]

These days, I think any disparities between manuals and automatics is much narrower than it used to be. There are still a few cars that will get 3-5 combined mpg better with a manual but those seem to be a rarity. I've read auto writers describe certain cars as 'one of the few' where driving a manual version can still yield noticeably better mileage. That's probably accurate for the majority of newer cars.

Beyond the rise of CVTs, things like newer engine management systems, smart alternators, 6 to 9 spd. autos, dual CVVT, and direct injection will narrow the gap versus 15 years ago. I only buy manuals and I've yet to buy a car where real world mileage is better with an automatic ( both told anecdotally and in published test results ) but I'm sure it still depends on the car and driver as much as it does newer technology and tweaks done for economy.

 

[Dave Sherman]

My '04 Honda CR-V had slightly lower highway mileage than the equivalent auto, because the 5th gear ratio was actually lower than the automatic's 4th gear. I guess they wanted the cruise control to be able to keep it tooling up the hills in 5th without having to lug the engine or making the driver downshift. Indeed, at 70 it was still turning about 3,200 RPM.

 

[Fastcompany]

Autos require more hp to be moved regardless of gears. If you cruise without changing speed and the final gear ratio is the same a manual will always get better mpg. Stop and go can be improved by having a 8 speed auto but its not that much. In America here every thing is going auto because we are lazy. I drive Ferraris with F1 gear boxes and I think they are [censored]. Give me a 5 speed stick over an auto any day.

 

[simple_gifts]

Quote:

In America here every thing is going auto because we are lazy.


I said the same thing when I was forced to buy a car with a starter.

 

[BrocLuno]

Short answer - NO ...

If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...

 

[Rand]

They can be but usually are only vastly better in specialized vehicles such as the prius.. where a manual would be inconvenient/hard to design.

In cheating the epa cycle they can have many advantages.. but
lugging along at 1200rpm in real life is annoying even if you get 2mpg better at 40mph.

A properly engineered vehicle with a manual can be just fine/better... the cruze eco or diesel 6mt for example.

 

[Pop_Rivit]

Originally Posted By: BrocLuno
Short answer - NO ...

If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...


Interesting. Then why are automatic transmissions in tractors growing by about 3% each year? And Volvo's I-Shift accounts for about 47% of their production? The take rate for Mack's mDrive is about 40%, and Eaton's UltraShift Plus has a 25% take rate.

I even found this in one article-it's a rather interesting quote:

Quote:
“I can understand why fleets like ATs,” he says. “It’s all about fuel economy. You know – ‘Instead of teaching new drivers how to drive, just give them all an automatic transmission, and turn them loose on the highway.’ ”

And I also found this odd quote.
Quote:
For fleets, though, the appeal of automatics goes far beyond driver preferences, with safety and fuel economy topping the list. “We’ve found that automatics help with driver recruitment and retention,” Spurlin adds. “They are also a large help with safety because the drivers can stay focused on the road or the task at hand instead of shifting gears.” Also, drivers do not get as fatigued with an automatic since they do not have to shift gears constantly, he says.

And this weird quote from a trucking article. Why do you suppose these articles, written by people who actually research sales figures and talk to trucking companies, would write something like this?
Quote:
Automatic transmissions continue to make inroads in trucking. Now, engines and transmissions are sharing more data, so performance issues are getting smoothed out. ATs now are being spec’d on a significant share of new trucks for reasons including fuel economy and easier driver training – and the trend is likely to continue.

 

[Fastcompany]

Originally Posted By: simple_gifts
Quote:

In America here every thing is going auto because we are lazy.


I said the same thing when I was forced to buy a car with a starter.


Hey a bike that I have to kick over is high on my list! And sorry starters are smart. Hand cranks were just a good way to get hurt lol.

 

[yvon_la]

Usually gas pedal feel on a manual is feistier witch tend to make people fiestier .if the gas pedal was calibrated for similar feel .it would be almost equal (yes auto still got an edge ,about 3% max ) which I would recommend? Automatic .why ? Put Allison yes 295 oil in an auto and it last a long time ,can I say forever) the down side? 50 $ a gallon .

 

[JHZR2]

Originally Posted By: BrocLuno
Short answer - NO ...

If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...


+1. Heavy trucks have the "luxury" of larger sumps, more gearcratios, and larger/heavier equipment to make it viable/reliable. They haven't seemed to have bit.

Manuals will always be simpler, less maintenance intensive, lighter, and cost less (until/unless economies of scale affect that). The 6+ speed ATs that cause the very high mpg numbers certainly make the simplicity claim even less in favor of the AT, and almost certainly go along with the claim of being heavier too.

The issue with manuals has really been the lack of engineering dollars compared to the automatics. Automakers have generally had a lot more engineering dollars put into ATs to insure that the shift as smooth and compliant as possible and have all the appropriate logic and controls integrated properly. Because they have more nowadays many more forward gears then a manual transmission and because of the shifting logic under any sort of viable condition is done for the driver they can always have a decent ratio selected.

Meanwhile the marketing people seem to be orienting manual transmissions as a performance option, and some trims and with the gear ratio said that is more aggressive that it would really need to be. A truly well-thought-out manual transmission is a thing of beauty to operate. Having owned manual transmission cars from a variety of manufacturers, I will say that really only BMW has done it right, with the set of ratios that makes driving under all conditions including traffic completely non-fatiguing, So combine a poorly selected set of ratios with a bias towards having them also be a bit more aggressive in terms of making the car feel "peppy" and high performance (even if it's not), I knew just have a set of physics which is not going to be is optimized for operational efficiency based on your ratios.

ATs are winning out because the engineering challenges of CVT's are too difficult, and the design attributes of dual clutch transmission's are too expensive. A six or seven speed manual transmission would have every advantage over an automatic, assuming that it was set up with a traffic friendly first and second gear, the way the BMW does it, and two overdrives at the top end to ensure economy. The main issue is that that the user might actually have to think and move.

 

[BrocLuno]

Originally Posted By: Pop_Rivit
Originally Posted By: BrocLuno
Short answer - NO ...

If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...


Interesting. Then why are automatic transmissions in tractors growing by about 3% each year? And Volvo's I-Shift accounts for about 47% of their production? The take rate for Mack's mDrive is about 40%, and Eaton's UltraShift Plus has a 25% take rate.

I even found this in one article-it's a rather interesting quote:

Quote:
“I can understand why fleets like ATs,” he says. “It’s all about fuel economy. You know – ‘Instead of teaching new drivers how to drive, just give them all an automatic transmission, and turn them loose on the highway.’ ”

And I also found this odd quote.
Quote:
For fleets, though, the appeal of automatics goes far beyond driver preferences, with safety and fuel economy topping the list. “We’ve found that automatics help with driver recruitment and retention,” Spurlin adds. “They are also a large help with safety because the drivers can stay focused on the road or the task at hand instead of shifting gears.” Also, drivers do not get as fatigued with an automatic since they do not have to shift gears constantly, he says.

And this weird quote from a trucking article. Why do you suppose these articles, written by people who actually research sales figures and talk to trucking companies, would write something like this?
Quote:
Automatic transmissions continue to make inroads in trucking. Now, engines and transmissions are sharing more data, so performance issues are getting smoothed out. ATs now are being spec’d on a significant share of new trucks for reasons including fuel economy and easier driver training – and the trend is likely to continue.





Most of that talks about driver issues - not real fuel economy. And many of the trannies mentioned may be 2 clutch designs like paddle shifters in cars. They are computer controlled manuals with shift adapters (usually hydraulic or air powered).

And, even though you offer good examples, they are not over 50% (yet). They are getting closer. But a true automatic like an Allison with torque converter will not equal a manual in the hands of a knowledgeable operator.

Now, the issue with the young'uns not knowing how to drive a multi-box manual, and getting lost in the gears, and loosing site of the road - is not an efficiency issue (fuel wise), but may be a fleet operator bottom line issue ...