auto vs manual trans MPG

[NateDN10]

There's a very good article on the history of automatic transmissions at Ate Up With Motor.

GM's first Hydra-Matic AT came out in 1940 for Oldsmobile and 1941 for Cadillac. In 1941, 40% of Olds buyers and 30% of Cadillac buyers went for the AT.

 

[rationull]

Originally Posted By: sciphi
Realistically, how many people will plunk down for a brand-new MT car just because they feel like it? There has to be some reason like much higher MPG or substantially lower purchase cost to get a manual car new off the lot today. Add to that the trend over the past 10-20 years of only offering a manual in the decontented base version of a common econobox or midsize car, and it's obvious to me why very few folks drive a manual anymore. Locating a MT car with any options has been next to impossible the past few decades.


My wife and I have, 3 times. Leaving the WRX out of it, though (because there's no other option even if you wanted one), we bought a Civic for me and a Mazda3 for her, both with 5 speed MTs. They're not stripped models, either.

In either case, would not have settled for an AT. I agree that locating them can be problematic, but honestly, if I couldn't have found my Civic in an MT then I would've bought something else. If I couldn't find anything new and comparable, then I would've just repaired my previous car or bought something older and/or more beaten up. Only exception would be if we were looking for something like a minivan, of course, or a truck where I probably wouldn't want to deal with hills while towing w/ a stick shift.

This is not an argument for the superiority of MTs, but I just wanted to say that to some people (myself included, for now), the transmission choice is just as much of a dealbreaker as having enough seats, a big enough trunk, high enough safety ratings, etc. If MT were a for-cost option and AT were standard, I still would've picked MT. I just like it and it works out well with the driving I do. The higher real world FE and lower lifecycle costs (in some cases) are just icing on the cake.

 

[AccordV6MN]

Originally Posted By: d00df00d
Originally Posted By: SteveSRT8
It's really idiotic to imply that a stick automatically guarantees a better driver. It doesn't.

Promoting good driving habits is not the same thing as guaranteeing a better driver.


I concur. For instance, there are many stick drivers that is always have their foot rest on the clutch pedal.

 

[SteveSRT8]

That's precisely what I'm talking about.^^^

And Doodfood, after many road course track days I must say it seems about equally divided to me between stick drivers who can and cannot. Having a clutch doesn't seem to promote anything to me, it would actually seem to confound many drivers who are seemingly unable to handle a stick shift. For me it's second nature as I never even owned a slushbox as a daily driver until I was 30-something.

I once watched a guy go backwards off the infield raceway at Homestead due to a downshift at the entrance to a corner. Luckily only his ego and his vehicle were smashed. I'm sure the Skip Barber people thought he could drive!

Just one of dozens of examples I've seen where so-called 'enthusiasts' could not drive a stick.

 

[D189379]

Originally Posted By: d00df00d
Originally Posted By: D189379
Doesn't an auto usually weigh quite a bit more than a manual trans?

Usually, yes. But...

Originally Posted By: D189379
I was always under the impression that the extra weight + final drive ratio accounts for the only difference in mileage.

No.


this is usually the part where you tell me why you disagree with me. Man, the internet is getting so lazy.

 

[NateDN10]

Another thing to consider is that gas engines operate most efficiently near the torque peak with wide throttle opening. This reduces throttling losses.

However, it's impossible to operate an automatic in this manner because the wide throttle will prompt a downshift, or at least unlock the converter.

 

[d00df00d]

Originally Posted By: D189379
Originally Posted By: d00df00d
Originally Posted By: D189379
Doesn't an auto usually weigh quite a bit more than a manual trans?

Usually, yes. But...

Originally Posted By: D189379
I was always under the impression that the extra weight + final drive ratio accounts for the only difference in mileage.

No.


this is usually the part where you tell me why you disagree with me. Man, the internet is getting so lazy.


It's been covered ad nauseum in the rest of the thread.

What was that about lazy?

 

[SteveSRT8]

Originally Posted By: NateDN10
Another thing to consider is that gas engines operate most efficiently near the torque peak with wide throttle opening. This reduces throttling losses.

However, it's impossible to operate an automatic in this manner because the wide throttle will prompt a downshift, or at least unlock the converter.


Sorry but you are generalizing across many platforms. My car easily allows me to command and hold any gear at any time up to the rev limiter. I'm sure many others do this as well.

 

[ffracer]

Originally Posted By: SteveSRT8
It's funny how a transmission design can become almost religion. Great fun to hear the long winded defense of the stick shift, but it's mostly baloney.

Despite the huge harangues above the slushbox is here to stay. It's really idiotic to imply that a stick automatically guarantees a better driver. It doesn't.

It's also ridiculous to imply they guarantee a longer lifecycle. They don't.

What we're really discussing is a driver dependent thing. Not hardware. But it's fun to read.


Thanks for the compliment of long windedness....

I am a driving instructor/racer and you are one who runs track days, you know better or are missing the point.

No one has suggested the transmission has to do with driver ability. I get tons of people who have no clue what they are doing with a manual or an automatic. The manual has more potential by default, because isn't passive, it require driver planning and ability.

Lifecyle has to do primilarly with how you drive the car. if you take a passive transmission (an automatic or CVT) and drive it hard, say on a twisty road, it will take less hard running, simply, because the driver has not planned ahead to match the rpms (the computer cannot predict the future) and massive changes in torque either wear out the coupling device (clutch or the torque converter or belts) or the gear drvieline. One gearbox is up to you, the other isn't. If you plan to keep it 200k+ - there is no option for performance enthusiasts, but a manual.

Rather than debate and argue with every performance driving school, racing series, car maker (including Chyrsler - any automatic Vipers?), most of the world (most of the world drives a manual), what does an automatic (passive shifting) or the coupling (torque converter or a CVT) do better than a manual clutch gearbox?

Anything at all? Besides easy to drive in traffic? It doesn't.

 

[sciphi]

About the only thing a true automatic transmission does better than a manual transmission is make money for somebody who isn't you. Think about it. ATF flushes using 10-12 quarts of ATF, recommended services at 30k miles, rebuilds every 140-160k miles or so. All of that makes lots of money for somebody. Likely that person isn't you. And you, the owner of the automatic car, paid more up-front for the privilege of paying more down the road!

Meanwhile, a manual transmission tends to be a bit lower-maintenance, and cheaper to maintain in general. A clutch is cheaper than a rebuild, and 2 quarts of gear oil every 40-50k miles isn't too bad. The purchase price of a MT car is also cheaper up-front.

 

[dwcopple]

Originally Posted By: ffracer
what does an automatic do better than a manual clutch gearbox?

Anything at all?
Ferrari must think so...