My G37xS sedan averages 22 mpg in local highway, some town driving. Average speed display shows about 36 mph. My '04 Maxima averaged 24 mpg in same area. Expected lower mileage with the higher hp, so no complaints here.

 

Today's trip (figures from dash display)
104 miles round trip - 98 interstate, 6 in town
Average speed 62 mph
Average fuel consumption 25.8 mpg.
Average temperature about 42 degrees (min 31, max 49)
Winds light
Start elevation 7200, max elevation 8600, min elevation, 6200 ft
Miles on car 2020 at end of trip.

Obviously going up over the hill twice would lower gas mileage and the car does only have 2000 miles on it, but still better than EPA estimates.

I wonder too what altitude does to gas mileage. Clearly less HP produced by the engine at 7200 feet and I would assume that makes the engine work harder to attain a given speed and thus decreases mpg. Anyone know for sure?

 

You obviously dont drive your car HARD enough if you are still getting around 20mpg.. lol

 

13.5-14.5mpg sounds right if you do alot of city driving with a heavier than normal foot.. I had a coupe and if you do your research, alot of the Coupe owners that drive in the city alot average 12-14mpg

 

Funny thing is I traded in my 330hp G37 for a 416Hp Is F And with the same driving style, I averaged 14.5mpg on my G but I have an average of 17mpg on my F now.. I guess that 8spd trans really works wonder.. 1500rpm at 60mph cruising averaging 30mpg on the highway!!

 

Same here. After the initial reset I am getting 21-22 average with a 70/30 split highway/around town. If I reset once I get on the highway and drive 60/65 it will register an average of 26-27 mpg. Once I hit the streets, it quickly drops back to 20 or so. I would imagine city driving along would register mid-high teens.

 

I can get +35 mpg on the highway, I just have to be going 85mph. I think the G37's sweet spot is right around 80mph. You can easily get 30 mpg average at that speed.

Secondly, I think that 7th gear in the G is too freaking close to 6th. They could've spaced it out a bit more so that 90mph is around 2500 rpm.

 

Can anyone else match this. Seems a bit odd considering all of the other posts on G37X mpg posts. If it is true (and perhaps it is), then I am going to start driving faster.

 

If you don't believe me, just set the gauge screen to mpg (the one that goes from 0 to 60) and get on the fwy and drive around 80 and just look at it. Conversely, you could to to info -> fuel consumption and reset it right before you enter the fwy, then cruise around at 80 and see what number comes up. The whole bar up to 30 mpg should be either almost full or full.

 

Hey - I clearly said it might be possible. I know how to view all the screens that show fuel consumption. Just for the heck of it I will try this on a flat section of I-80 west of here. I suppose 20-30 miles should be enough. I will report back.

 

Haha, sorry for the seemingly hostile response. I supposed saying, "Hey if you don't believe me", isn't the best way to answer. But yeah, try it out and report your findings. Keeping in mind though, my sedan isn't an X. But even then, 30mpg at those speeds shouldn't be too far out of reach.

 

Okay - here it is.
At about 4:30 pm, I started the car and did a 20 minute warm up drive. Then I went to a level section of I-80, brought the car up to 80 mph turned on the cruise control and reset the mpg/mph screen on the drivers console.
Numbers took about a minute to reappear. They read 79.5 mph and 26.8 mpg.
I drove for 30 miles. Virtually flat. Out and back drive with very little wind. Temperature 24 degrees F. Very light traffic, only had to pass three semis.
At the end of my 30 miles the readings were 23.8 mpg and 78.9 mph. Even a one half block turn around with only on stop sign dropped the mph to 76 before it started to climb again. However, time wise this was probably less than 4-5 minutes. Stayed easy on the gas getting back up to 80 mph and turned on the cruise control again.
Since I warmed up the car very well, I doubt temperature had much effect on the mpg. I assume that the high altitude has some effect but very difficult to estimate.
So I failed miserably to achieve 30 mpg at 80 mph. I would have tired 85 but WHP frowns on that.
So FWIW, there it is.

 

my '09 g37x coupe 1102 miles on it.... full tank just averaged around 379 miles... my '08 g37s coupe i used to maximum get 318...80/20 highway/local split

 

Don't expect to get numbers over 30mpg, even on flat highway. I'm not saying crazjayz is lying, but those results are, as they say, "not typical". Most people can get about 26-27 on the highway if it's mostly flat and you don't gun it too much. It's pretty hilly where I live, so I'm happy to get 17/25 they way I drive.

 

I am actually pleased that I am getting what the sticker said. But, as noted above, a lot of mpg results have to do with driving habits. I'll bet with similar driving habits, my mpg will continue to increase as the car gets a few more miles on it.