^Exactly. I wasn't coming down on you about "miles-per-tank" just saying your being unaware of the 20 gal tank and refueling at 17 gal is an excellent example of how poor a measurement miles-per-tank really is.

 

The only accurate way is to fill up, set the trip odo, then fill up again and divide the numbers

 

i drive like an ******* and get around 325 miles to about 17 gallons

 

I stop complaining after the first year of owning it.

 

well today i basically filled it up to half tank when my light turned on, so i got about 12 gallons, and i drove 90% highway, and turns out i only drove up to 108 miles and the light turned on, i kept driving for about another 20 miles..... sound right then?

 

still hard to gauge.. i would save up your money and fill it up all the way, then measure your usage...

 

That really is the best way to do it.

Fill tank, hit trip reset and drive. At some point, go fill the tank again. Try and go to the SAME pump again. Different brand pump nozzles sometimes shut off sooner than others. Top off the tank, then divide the miles on your trip reset by the gallons you pumped. Then hit trip reset again and do it all again. After a week of this, average out your economy.

91+ will give you the best numbers. 87/89 may expereience reduced economy. If you can't afford to fill the tank with 91+ a few times, then perhaps the cost of ownership of a G35 isn't for you.

 

+1.

There are a lot factors to consider here.

1) You live in CA which is known for emissions friendly fuels which net worse MPGs and performance. It's to be expected you're seeing 5% less fuel economy simply because of the fuel type. I deal with a similiar thing here in Kansas City as our fuels tend to be blended with more ethanol than most.

2) You live in San Francisco. Lots of hills and grades kill performance, especially in city driving.

3) What type of G do you have? Is it an X? If so, expect about 10% less mpgs than a RWD G. What about wheels? Are they larger or wider than stock? Larger and wider wheels/tires kill mpgs. How about tires? Are they sticky summer tires or hard all season tires. Summer rubber will increase drag.

4) How fast are you going on the highway? Is it constant speed or is it variable. Lots of hills or grades? A slower sub 65mph steady cruise will result in significantly better hwy mpgs.


278 miles to a tank of 80% hwy and 20% city isn't terrible considering where you live. Assuming you're filling up when the light comes on, that means you're filling up with 16 to 17 gallons. Your mpg overall is anywhere from 17 to 18 mpg. Not great, but it's fairly normal. The automatic's mpgs tend to get hit pretty hard in city driving thanks to the inefficiencies of an automatic transmission. If you were to do pure highway driving, you'd definitely be seeing closer or exceending 400 miles to the tank. I typically see 18 to 20mpg (~300 miles when the light comes on) in city/hwy driving depending on the season and wheels I'm running. In pure hwy driving going 65mph, I've seen as high as 29.8mpg or ~480miles on 16 gallons. I typically see 25-26mpg. Either way, that's a HUGE swing in mpg.

 

bleh... well i do fill up all the way with 91, its just that i read on here that filling up half way is always better lol so i do that, and i dont really drive the G in the city too much because i dont trust people out here when they road rage and crap, i usually take out for weekend and just when i chill, but going to school is hardly any hills just basically a straight away. i have a rwd G with the sports rims stock 18 rays i guess. but ill try again to fill up all the way and see what happens to me thanks everyone!!

 

Why would filling it up halfway be better?

All you are saving is maybe 70 pounds of weight by not topping it up.

 

Ok dude. Yes, the car will get slightly better fuel economy, but not much.

1 gal fuel = ~6lb. So if the tank is truely 1/2 empty (10 gal) that would be saving 60lb.

BUT, the needle on the dash isn't very accurate, and I would venture that it's halfway mark is not 10 gal.

Furthermore, if you're trying to calculate MPG based only off of 10 gal, the margin for error becomes wider.

The best way to come up with an accurate MPG is to fill the car with 91 or better, reset your trip meter, then every time you put gas in it, write down the number of gallons until you've put in, until you go through 60 or more gallons, the fill it completely up one more time (at the same station as before) add that last fuel up onto your running total, and divide the number on your trip meter by the total number of gallons you've put in over the last few fuelups.

 

And remember that the difference between 20mpg and 17mpg will cost you no more than $500 over the course of a year. No reason to be ocd about gas mileage. Enjoy the ride!

 

sweet sounds good ill try that then. thanks for all the advice and stuff

 

i used to get 180 per tank. thats with my old G sedan filling up when the light came on.

 

"ima go down on you and then come back up real slow and f*ck you" yours truly GAS PRICES!