Yes ATs are harder but not completely impossible, my 98 buick I am stuck with for a while should be proof well enough of that.
Also Big Dave, I could get approx. 24mpg with the 93 350 gas suburban we use for crafts on the highway, you need to probably drive a little harder than you are used to and vary your speed quite a bit. Since that weighs about 2k more and is as aerodynamic as a brick you should be able to tweak your SS better than a Suburban.
(I assume Big Dave has a scamguage so he can see what the car does under different throttle and situations.)
One thing on highway driving I have noticed on all my AT's is that the MPGs will drop after a while sometimes while going DOWNHILL under light throttle, you instinctively push in a little to hold speed above downshift and the FE drops and speed continues to drop. Then I notice my flat road steady state MPGs are severely dropped after one of these type of incidents.
Oddly enough letting off the gas while coasting downhill and allowing the GPH to drop to idle levels seems to "reset" my fe after the above happens so when I push the throttle back in my FE stays hi, my power is improved and I can once again maintain speed without suffering reduced FE. Trouble is when I let off the gas it doesn't just drop, it drops down then pops back up to .75gph then sslllooowwwly drops to my idle fuel rate around .4gph so I need a long gentle downslope to maintain speed.
Some have said its because of my lockup, some have said its a case of detroit fever where the motor has been running leaner than normal and than the computer corrects, whatever the case I am slowly figuring out the AT vehicle's "quirks" at least on the Buick.
Something else I have noticed, my Dodge crewcab drops fuel consumption instantly to idle levels when you put it in neutral which makes a huge FE difference than leaving it in D and suffering double the fuel consumption. My Buick is the opposite using less fuel when left in gear, odd. My Dodge also uses about the same amount of fuel under heavy accerlation (GPH) as when you accelerate more moderately, wheras my buick is also reverse, your better off with moderate on the buick than heavy.
Another odd quirk is that my buick once the motor is warm drops fuel consumption linear with the throttle when its in open loop after a restart at a stopsign or light, so when I take off and then coast to the next light my consumption rates drops instantly to .52gph instead of hovering at .75gph for about 5 seconds. So I am actually better in open loop with a hot engine in town than with it left in closed loop.
Also you need to take care coasting your auto since there is a point where your FE drops below an acceptable level since you are forced to leave the
motor on. I try to end up somewhere around 15-18mph when I have to then come to a complete stop, below that ruins my FE except if I know the light is about to change then conserving momentum helps.
Good Luck Big Dave, a little more patience and you will find that hypermiling an auto can be fruitfull as well but the techniques you use on a manual DO NOT directly translate, you need to figure out the quirks and drive strangely to get better MPGs on an auto. You need to feather and play with the throttle much more than you are probably accustomed to. You will also need to plan your routes more carefully to avoid stopping at all costs. In stop and go in town driving can easily be half the MPGs as highway driving on a typical auto, so you can drive up to double the distance to get around those situations in an auto and still burn the same amount of fuel.
Quote:
Originally Posted by tasdrouille
The clichés have been tried, tested and proven effective on most of the vehicles. An AT by default makes hypermiling harder because you have to fight it most of the time. I tell people with a MT not to fear rolling heavily into the throttle and shift early, but I can't tell people stuck with an AT to punch it, because they have mostly no control over the shifting. There are so many variables that affect fuel mileage that the best advice to give people would be to head over here. But since very few people will do that, my generic advice is to take is easy, slow down and use your brakes as little as possible.
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