so, like if you're driving 40 mph, you get good mileage.

but, if you drive one miles per hour, even though your revs are one fortieth of 40 mph, you get worse miles per gallon(because you're practically idling).

so, what is the ultimate speed for maximum fuel efficiency? (2.4LT 5 speed)

 

I say 60, as when I am on cruise control at 60 on the interstate I get 42 mpg. I have 09 ss. Yet most of my driving is intown, so I average 21mpg.

 

i drive in town almost always and i get 24-27 mpg
just dont take off to "hard", and stop slow not abruptly
and on the highway 55-60 is probably best, but i took
a trip last month, and did 70-80 the whole time and still
got 28-30 mpg

 

If I set my cruise at 59 on the interstate I get 43mpg

 

There are many factors, such as wind condition and direction, terrain, etc. While "drafting" a semi, I have seen low 40's at 70, but for overall economy, mine seems to be in the low 60's. Find a flat open stretch of highway without much traffic (so you don't irritate the other drivers) and try setting your cruise control at 60, then bump it up after a mile or so and watch your DIC display set to instant fuel mileage. You will notice a drop in mileage every mile or so you increase. If you have an older HHR set it to avg MPG and reset it after you bump up the speed each time.

 

Depends on the terrain. If its pool table flat, with slight (and I mean slight) ups and downs cruise at 60 will net the best mileage. 55ish if you have some slight slopes.

There is a lot of things that you can do to get 35+mpg "intown" or in the city as I say, but I have a manual.

Truely I doubt that you can do better than 36mpg average at anyspeed using cruise.

The only way to do better is to drive it yourself. Is teh effort worth the work, you decide?

 

The best I've ever gotten on my 2.4 auto was 38 mpg flat terraine @ 55 mph driving across central Florida, using 87 octane. Since there seems that all gas is 10% ethanol my mileage has dropped by 10% recently. My overall average has been 30.3 mpg for nearly three years. Around town driving, I've been running a consistant 25-26 mpg.

 

Old Lars drive is an excellent example of pool table flat. The key is never accelerating to downshift, for hills, or passing. Tough unless you live one a limestone shelf :)

 

i was thinking the slower the better, but, conservation of momentum counts for something, eh?
i was coming home averaging 60 mph one night, and getting about 31 mpg, but when i sped up to 65, the gas mileage started going up, until it reached about 34.
maybe it was a tail wind? i don't know, but, slower is not necessarily better, in the grand scheme of things.

 

I keep to 55 mph, and have seen as high as 42.5 mpg, and this was not a flat land drive. I think I can top this number, but have not had the time to take any trips.