Impressed!!I dont need a prius!
01-19-12, 04:45 AM
#19
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That said, the "tank average" gets more accurate the more you drive on each tank. When you fill up, the number fluctuates wildly, and it's very easy to snap pictures of MPG values that are way out of line with reality. By the time you're ready for a fillup, even a jackrabbit start is unlikely to budge the number much, and the number should be far more accurate.
01-19-12, 05:11 AM
#20
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I keep track of my MPG's over time and over the last ear or so i'm sitting at an average of 24.7 70/30 mix of city/highway. The tank average is pretty dead on (within 1mpg typically) at the end of a tank. For the first 100miles it changes a lot.
I've compared the trip computer tank average with a manual calculation literally dozens of times, and mine too has never been off by more than a MPG or two.
That said, the "tank average" gets more accurate the more you drive on each tank. When you fill up, the number fluctuates wildly, and it's very easy to snap pictures of MPG values that are way out of line with reality. By the time you're ready for a fillup, even a jackrabbit start is unlikely to budge the number much, and the number should be far more accurate.
That said, the "tank average" gets more accurate the more you drive on each tank. When you fill up, the number fluctuates wildly, and it's very easy to snap pictures of MPG values that are way out of line with reality. By the time you're ready for a fillup, even a jackrabbit start is unlikely to budge the number much, and the number should be far more accurate.
01-19-12, 07:47 AM
#21
I love the gas mileage my IS250 gets as well! I keep track of everything separately to and do my own calculations to compare to the trip computer. Right now, it looks like the variable of real (calculated) MPG vs the trip display is somewhere between -2.5 and +1.8. I agree with Jbjones85 though, the first 100 miles on a tank it bounces around a lot, but after that it should be pretty consistent. For the first 25-50 miles i can get the car to read 40+ mpg. But after that 100 miles i'm usually right around 35-36 MPG, and then by the end of my tank i'm usually at 32-34 somewhere, unless i do some spirited runs, then i'm more like 30. Based on my calculated MPG, i'm getting between 30-34 MPG on mostly highway commutes. I don't know if anyone else has noticed, but the trip computer is more off when you drive mostly city than driving mostly highway. City driving is when it can read 2.5 mpg off from the actual MPG.
then again I do a lot of city driving 
01-19-12, 11:07 AM
#24
2 mpg difference for me also
Also, We average 27 mpg in the convertible with 85% highway, 15% city and the topless 50% of the time.
01-19-12, 04:39 PM
#26
Holy ****.
No offense to anyone in this thread... especially you OP...
But the "MPG" gauge on your instrument cluster is the ****TIEST way in life to know your MPG's...
One time on a road trip to Arkansas, I filled up, Reset to 0.. went 70mph cruise control on for over 5 hours... it shows 36mpg...
I stopped by a gas station and filled up back to full and divided my miles driven since last fill up by the gallons of gas used and it showed 25mpg... the "amazing" instrument cluster mpg gizmo way 11mpg off... and yes, that was reading the one that says "tank average"...
That gizmo is a THEORETICAL calculation...
the vehicles ECM looks at numerous variables such as but not limited to the amount of fuel left in the tank, engine rpm, engine load (load is determined by the MAF, and the amount of air passing through it as well as Throttle position) and im sure HUNDREDS of other factors...
It just uses these factors and determines what your "MPG" is and displays it on the instrument cluster...
It is WAY off.. on every SINGLE CAR I have EVER driven...
If you ever go by that thing your a TOTAL moron.
Good luck.
No offense to anyone in this thread... especially you OP...
But the "MPG" gauge on your instrument cluster is the ****TIEST way in life to know your MPG's...
One time on a road trip to Arkansas, I filled up, Reset to 0.. went 70mph cruise control on for over 5 hours... it shows 36mpg...
I stopped by a gas station and filled up back to full and divided my miles driven since last fill up by the gallons of gas used and it showed 25mpg... the "amazing" instrument cluster mpg gizmo way 11mpg off... and yes, that was reading the one that says "tank average"...
That gizmo is a THEORETICAL calculation...
the vehicles ECM looks at numerous variables such as but not limited to the amount of fuel left in the tank, engine rpm, engine load (load is determined by the MAF, and the amount of air passing through it as well as Throttle position) and im sure HUNDREDS of other factors...
It just uses these factors and determines what your "MPG" is and displays it on the instrument cluster...
It is WAY off.. on every SINGLE CAR I have EVER driven...
If you ever go by that thing your a TOTAL moron.
Good luck.
The multiple sources of irony are kind of overwhelming.
01-19-12, 07:58 PM
#30
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