Pros and Cons of Manual vs Automatic Shifting?

mellowtoad · 09-23-2009, 01:40 PM

Hey folks, I've been working on driving my car in manual since I got it and have learned much about it and can do a pretty good job of shifting. I do have a couple of quick questions for you. I'm wondering if there are any pros and cons to each different method of shifting. I feel that when I drive in manual, the shifting is smoother than in automatic mode. Are there any other benifits to that over automatic? Does gas mileage increase in either mode?

Old smart · 09-23-2009, 01:53 PM

If you can get your mind beyond smartUSA, you will realize that in the rest of the world the basic intent of the transmission is a sequential manual ("softip"); all models have it. An additional auto mode is added in the high-end models ("softouch"). All US models have the auto mode to open sales to our many who are intimidated by the thought of a manual transmission. Manual shifting is obviously intended to be the more efficient (otherwise, everyone would get a rubber shift with a manual as an option).

forestacademy · 09-23-2009, 02:04 PM

It all depend on how you drive it. Many folks who drive it in manual do it to gain performance. If they are driving it to gain performance then they most likely are not driving it for MPG's.

So the answer is....

your results may vary

**jwight** · 09-23-2009, 02:12 PM

I believe (since I can't find a copy) the smart USA pdf with tips to improve your mileage speaks about using the "D" or auto mode vs. the manual mode. The autoshift program is optimized for better mileage, not performance (which is why some don't like it.)

**JPaul** · 09-23-2009, 02:18 PM

Here:

But no mention of mileage in either mode. The "D" mode has been optimized for best mileage we've been told.

tvengineer · 09-23-2009, 02:27 PM

YOu are going to open much debate on Manual vs. Automatic as far as fuel economy goes...

For me this is my first car with automatic (and I've been driving for 37 years)..

so manual to me is not foreign at all..

I do use automatic most of the time.. but there are many times when manual is better..

When I need to dart accross a busy intersection.. i would rather choose the time to shift then leave in auto where it may decide to shift just when I need the power to get accross traffic..

ANother time, on my way to work each day.. I leave a stop light and 1/2 block later have to climb an overpass.. if I leave it in auto.. it does not know the overpass is comming.. so it shifts all the way up to 5th.. only to have to downshift when I hit the up grade... so I use manual if I know something that the car does not... like a hill is comming..

In city drving.. I know a stop sign is comming up in a hundred feet or so.. the car doesn't... the result is a lot of useless shifting, that I would not do in manual... that contributes to the "jerky" feel many complain about..

lastly.. getting on the interstate.. manual lets you accelerate more quickly (IMHO).. only trouble there is, that once on the interstate... and many miles later when I finally get off.. I mostly forget that I am in manual and that first start after a stop I get reminded

forestacademy · 09-23-2009, 02:47 PM

Quote:

Originally Posted by tvengineer

lastly.. getting on the interstate.. manual lets you accelerate more quickly (IMHO).. only trouble there is, that once on the interstate... and many miles later when I finally get off.. I mostly forget that I am in manual and that first start after a stop I get reminded

Bingo!!
Unless I'm driving truly in the city, Its usually a min of 5 miles between stops. No way I will remember I'm in manual at the next stop sign and I will remember when it starts winding up as I pull away.

For me out here in the country, I find the jump to manual useful when its time to pass some one. It's nice to have the control when passing that farm implement in the country.

Jpaul, I don't know where you found those wacky instruction

but that's not what jwight was talking about.
Now the search is on

Edit - http://ne.edgecastcdn.net/800E0A/www...el-Economy.pdf Page 2
I don't know how to copy a section out of a PDF, but I have seen others do it.

**jwight** · 09-23-2009, 03:18 PM

Quote:

Originally Posted by forestacademy

Bingo!!
Unless I'm driving truly in the city, Its usually a min of 5 miles between stops. No way I will remember I'm in manual at the next stop sign and I will remember when it starts winding up as I pull away.

For me out here in the country, I find the jump to manual useful when its time to pass some one. It's nice to have the control when passing that farm implement in the country.

Jpaul, I don't know where you found those wacky instruction

but that's not what jwight was talking about.
Now the search is on

Edit - http://ne.edgecastcdn.net/800E0A/www...el-Economy.pdf Page 2
I don't know how to copy a section out of a PDF, but I have seen others do it.

That's the one - thanks!

Quote:

Fuel Economy Tips
Operate in D (drive mode). The shift points are set for optimum fuel economy.

**JPaul** · 09-23-2009, 03:37 PM

The link
http://www.smartusa.com/Downloads/Ho...el-Economy.pdf
has been added to the sticky FAQs/DIY in Operation & Maintenance.
Thank you.

Ron F · 09-23-2009, 06:37 PM

I use manual almost all of the time. I refuse to believe that shifting into 5th gear automatically at such a low RPM is good for the engine. You can hear the engine lugging and that can't be good for it. This is Smarts way of getting better MPG. It might get you better mileage but I'd rather give up a few MPG and have the engine last longer. I've been driving for 58 years and have never had an automatic transmission that shifted into the higher gears at such a low RPM. I won't shift into 5th gear until a least 48 to 50 MPH and am convinced that this puts less strain on the engine.