MPG's --- A/T vs. MT

[tbm3fan]

Originally Posted By: rjundi
A well driven manual with an aware smart human can achieve higher MPG than an automatic. How? A human can see far ahead and anticipate the proper shift well ahead and proactively. An automatic is reactive to conditions occurring at he moment.


+1

 

[Whimsey]

With the MT I can drive it like an AT or better during "normal" driving. Then I can drive it enthusiastically when I want to and enjoy the vehicle much better. Of course if you commute in bumper to bumper traffic daily then an AT is a better option, sad to say. I'm lucky I don't at this point in time. "Save the manuals"

Whimsey

 

[GeneralEclectic]

This discussion has been around as long as there has been a choice between auto and manual transmissions. Unfortunately the answer is that there IS NO ONE ANSWER because there are too many variables. The two biggest in my opinion are 1) the skill of the driver of the manual transmission (and I've ridden with some real incompetents) and 2) the thermal efficiency map of a given engine type. Without knowing the efficiency map, you simply can not choose operating conditions optimally. You may ASSUME that you "know" how the engine responds, but I'm pretty sure that with current technology engines (direct injection, variable valve timing, closed-loop stoichiometric mixtures, etc) you just don't. Your intuition might tell you, for instance, that 5th on this long slight upgrade achieves better efficiency, when actually 4th and higher engine rpm yield a few % better.

Problem is that only the engineers at the car companies have the efficiency maps. That is, unless someone with access to an engine dyno wants to remove one from a vehicle and make the plots for himself. I haven't ever seen any though.

Anyway, the engineers at the car companies have those efficiency maps in front of them when they choose operating parameters for the automatic transmissions. No doubt the principal input to the programming process is the EPA fuel mileage test cycle.

 

[supton]

I haven't owned my truck (automatic) long enough to make real good observations; but... I bought in April, which is the tail end of winter. I would force downshifts so as to engine brake, as that's what I've done for a long time on my manual transmission. First three tanks of fuel were 16.8mpg. I then stopped driving it like a granny so as to see how bad it would be, if I were to just drive it normally--so I started using just Drive. Wound it out once or twice. Got 18.9, 20.7, 20.7. Is that from summer gas and warmer weather? If anything the shorter trips came after it warmed up, so the first lousy tanks were generally start, drive 45miles, stop with less stop&go than the latter tanks. Decided I could afford brake pads for the boost in mpg; not used to having to use the brakes so much.

 

[SteveSRT8]

As an example, the new Mazda was significantly SLOWER with MT than AT. And the AT gets a wee bit over the MT in the EPA cycles.

Modern vehicle drivetrains are getting pretty sophisticated, manuals are an endangered species.

 

[badtlc]

Originally Posted By: SteveSRT8
As an example, the new Mazda was significantly SLOWER with MT than AT. And the AT gets a wee bit over the MT in the EPA cycles.

Modern vehicle drivetrains are getting pretty sophisticated, manuals are an endangered species.


The CX-5 flies in the face of your post. Manuals are getting fewer because people would rather text and drive, not because they are inferior.

 

[SteveSRT8]

Originally Posted By: badtlc
Originally Posted By: SteveSRT8
As an example, the new Mazda was significantly SLOWER with MT than AT. And the AT gets a wee bit over the MT in the EPA cycles.

Modern vehicle drivetrains are getting pretty sophisticated, manuals are an endangered species.


The CX-5 flies in the face of your post. Manuals are getting fewer because people would rather text and drive, not because they are inferior.


Completely missed the point. Manuals require too many compromises in emissions and fuel economy programming as the driver may not select the 'best' gear compared to the PCM.

Might be preferred by DRIVERS but not by engineers struggling for a 1% improvement on CAFE!

 

[hattaresguy]

I used to be one of those manual fans with no traction control, ie I can do better than any computer types.

Than I started to get some wheel time behind some pretty good modern cars.

Now their is nothing I can't do that a computer can't do faster, and better sometimes.

Its like the new fighter jets, they would fall out of the sky without the computers keeping them in the air. But they can out turn just about anything.

I can slide say an old M5 with the traction control off and look cool, but a new AWD Panamera GTS will just slip right on by.

Technology marches on, its not the 1990's anymore. Now the only reason to get a stick is because you enjoy it, and really that's reason enough.

 

[badtlc]

MTXs are also cheaper and statistically more reliable. Plenty of reasons to still choose them.

You can still get TCS with an MTX.

 

[buck91]

Originally Posted By: dparm
Originally Posted By: pbm
I'm happy to have gotten so many good responses to this thread.
What I'm getting is that an M/T is capable of getting the same, if not better, mpg's than an A/T (depending on the vehicle).
I'm getting the urge to pick up a Focus or Mazda 3 M/T as a commuter car. The only problem is the rest of the family doesn't drive stick...we'll see how it goes.
Thanks for the reply's.


I would not get an MT for commuting. You'll hate it within a few months, and you can bet that the clutch is going to get worn pretty fast. Nothing beats a good ole torque converter for stop-and-go driving. (even the good dual-clutch systems tend to be a bit jerky at low speed since they are still basically a MT underneath)



Dissagree Dissagree Disagree!! I'm in a '11 F150 with an auto, before that a '99 F250 auto for about 8 months but before that a '96 Mustang GT 5spd then an '11 Mustang 6spd for a couple years between the two and I gotta say I MISS the days of commuting in those cars. Really its a different experience when you drive a manual, just so much more connected and focused on driving. I'm counting the days until I can get back into something like my 2012

(Not that the F150 isn't fantastic!)