maybe if you ease that right foot a lil you wont have mpg or valve spring issues, eh?

 

You assume all speed limits are the same as where you drive?

live in the country, rarely if ever drive on expressways. The limit is 80 kph on all 2-lane hwys and I regularly drive between 95-100 kph (55-60 mph).

It's quite relaxing.

 

I average 22 MPG on mixed highway/city driving... I don't beat the car but I don't really granny shift either. I fill up the tank every time.

 

i took my spare tire and tools out and only fill up a little past 10 gallons per visit and i get between 250-280 mpg every time and i cruise at speeds of 70-75mph

 

I got 23 MPG when i didn't take it above 2.5k once. This was in an 04 G35x

 

I just got 27.2 on the navi screen on a full tank 98% highway driving. When I filled and did the math myself, I got 26.2. Cruise control, 6mt, totally stock except for blizzaks on 17s, 93 octane...

You are absolutely right that keeping the tank less filled will help reduce weight, but its not going to make as big of a difference as you think.

100 savings in gas weight
3500 gross wight, + 100lbs for super thin driver
100/3600
1/36 of 22mpg = 22.6 mpg.

I know that math is not really accurate to predict gas mileage or performance, but from a simple fraction you can see the gains here are not significant. It would be like removing a passenger from the car. Yea it will be better, but not by much.

However:
Constantly keeping your tank low means more evaporation.
It also means more surface area, which allows more water to get in the gas

I don't know how significant the above is pertaining to gas quality and mileage, but I subjectively feel that my engine runs smoother when the tank is full to the top.

Lastly, if you only have 6 gallons in your tank maximum, you have to fill up more often, which can mean more trips out of your way, more starts and stops, and more engine starts. Not to mention being inconvenient for any long drives.

Moral of the story, run from full to 1/8 a tank every time, unless you're gonna race.

 

has anyone noticed that using higher quality gasoline will indeed actually give better mileage compared to a no-name gas station? like shell 93 with V-Power vs a Sunoco? if so, how many extra miles per tank did you experience?

 

I think the reduction in timing caused by lower octane fuels robs more power than it affects mileage. I just always run the highest I can find.

 

Since when is Sunoco a no-name? lol

 

well you know what I mean...pretty much either V-Power vs Non V-Power. I know that shell/exxon/chevron/texaco all pretty much have it, maybe sunoco does too.

anyways, does it really make a difference?

 

i always fill up at a speedway or a meijers gas station so i have no clue

 

27

The X only gets about 19..well my X is getting 19..but i don't mind..price you pay for driving a fun car

 

well to be honest, if you reset the avg MPG right when you fill up, you can easily get a higher MPG readout. my first tank, i resetted it and was showing about 31-32 MPG. it's really not an accurate readout until you do a few tanks overall. after the end of my 2nd tank, it had averaged down to a measly 20.6

 

I totally agree, which is why I did the math after filling the tank: Mileage/gallons in, and saw an average of 26.2. Still pretty good; that's the first time I've ever gotten it that high.

 

yes, but the saving is most likely negligible.


I skip gears, and I stick to the speed limit (and it took me a loooooong time to develop this discipline) and I get the EPA 17-19 in town.

if i put my foot down for just one second my average drops down to 15. yea, your right foot is def the biggest factor