Fuel Mileage Computation
5th Gear Member
Joined: Oct 2005
Posts: 3,678
From: Southern California
... # of gallons (per the gas station pump)
Hand calculation also assumes that both your odometer and the gas station's pump are accurate. The on-board is good for a relative reading in most cases. Additionally, if you're not hand calculating AND resetting your average MPG at each fill-up, you'll barely see those changes to your fuel economy that indicate something is amiss with the car (i.e., low tire pressure, poor fuel quality, clogged intake filter...).
Hand calculation also assumes that both your odometer and the gas station's pump are accurate. The on-board is good for a relative reading in most cases. Additionally, if you're not hand calculating AND resetting your average MPG at each fill-up, you'll barely see those changes to your fuel economy that indicate something is amiss with the car (i.e., low tire pressure, poor fuel quality, clogged intake filter...).
thats why i dont believe manual calculation is any more accurate than the dash reading. gas pumps vary on how accurate they are in dispersing fuel. i know this whenever i fill up my little red tank for my lawnmower. 2 gallons on the pump display IS NOT 2 gallons in my tank. something is off the mark.
"+" or "-" 1mpg seems to be the margin for error.
Thread Starter
Joined: Jan 2009
Posts: 28
From: MT
thats why i dont believe manual calculation is any more accurate than the dash reading. gas pumps vary on how accurate they are in dispersing fuel. i know this whenever i fill up my little red tank for my lawnmower. 2 gallons on the pump display IS NOT 2 gallons in my tank. something is off the mark.
"+" or "-" 1mpg seems to be the margin for error.
"+" or "-" 1mpg seems to be the margin for error.
6th Gear Member
Joined: Jun 2007
Posts: 16,182
From: PA to KY ('07) to IL ('09) to MS ('10) to FL ('11)
Site Moderator of Fury!
Joined: Aug 2007
Posts: 5,104
From: Houston, TX
I get 15 mpg on average. I never look at the computer mpg but maybe once because I don't care what mileage I get, because I know it won't be good 
I do look at my boost gauge all the time though, and I am fairly sure if I could look at my boost gauge and gas gauge at the same time, they move in opposite directions almost simaltaneously.
I do look at my boost gauge all the time though, and I am fairly sure if I could look at my boost gauge and gas gauge at the same time, they move in opposite directions almost simaltaneously.
5th Gear Member
Joined: Oct 2005
Posts: 3,678
From: Southern California
I get 15 mpg on average. I never look at the computer mpg but maybe once because I don't care what mileage I get, because I know it won't be good
I do look at my boost gauge all the time though, and I am fairly sure if I could look at my boost gauge and gas gauge at the same time, they move in opposite directions almost simaltaneously.
I do look at my boost gauge all the time though, and I am fairly sure if I could look at my boost gauge and gas gauge at the same time, they move in opposite directions almost simaltaneously.
Gentleman's Relish
Joined: Feb 2005
Posts: 13,189
From: AZ
IF it's a Premium model is most certainly has it. It was one of the few available options on the deluxe models.
1st Gear Member
Joined: May 2009
Posts: 90
From: Maryland
2nd Gear Member
Joined: Feb 2009
Posts: 157
From: FL
thats why i dont believe manual calculation is any more accurate than the dash reading. gas pumps vary on how accurate they are in dispersing fuel. i know this whenever i fill up my little red tank for my lawnmower. 2 gallons on the pump display IS NOT 2 gallons in my tank. something is off the mark.
"+" or "-" 1mpg seems to be the margin for error.
"+" or "-" 1mpg seems to be the margin for error.