Lie O Meter credibility
 

Realizing that many on this forum refer to the overhead information console as the "Lie O Meter" I hand calculated four tankfuls of fuel mostly city with intermittent highway mileage.

Hand calculations revealed a 1.1 mpg difference the hand calculation was 12.7 versus 13.8.

The larger tires (2.7") in circumference would affect both the hand calculation and the information console.

So tell us how much your Lie O Meter prevaricates.

Stock mine is accurate, the more I turn up the power the bigger the fish tales...

Mine is usually close, stock tires and wheels.

The sg2 is also very close on distance traveled and fuel consumed, and it reads from computer too.
Reset at each fillup and realize it is showing a weighted average so if you drive highway for half a tank, stop n go the rest, distance to empty is off..

My .02
Actual speedometer is designed to be high vs. Computer knows true speed(sg2 is dead on vs. Gps).
Folks that use 285 vs 265 tires get the speedo dead on, but the computer based things (overhead, sg2) are now going to be off.

mines pretty close within .5mpg most of the time alittle closer.

the lie o meter has no idea the tire you are running in your rig...nor does it care. It is calculated based on distance and such. The larger tire in your situation is the same size I run and that equates to about 4 percent difference on real world odometer and actual odometer reading.

Meaning if I am going 60 mph I am actually going around 62/63.

You have to figure that in when doing your math to get a true reading. Want to test it? Watch your trip odom on the Interstate at the mile markers. It will give you an idea what is happening.

it really depends on your driving type for that tank.

short trips around town only - spot on
longer trips at highway speeds - spot on
mix n' match of both above - 1 to 1.5 off (lower)
either style of driving with idle time - 2-3 mpg off



it does an okay job averaging the #'s. But I have found my SGII to be much more accurate. And it helps get better MPG's because you can see the instantaneous effect your lead foot has on MPG's. So I'm less likely to floor it...all the time anyways

^ what he said.

My Ex does not lie, I don't have a Lie-o-meter, it's a government issue XLT. :-X22 But my Ultra-Guage is always within 1 MPG on every tank, I log and hand calculate every fillup, the U-G gets all of it's info from the OBDII connector.

The tire is going to skew all information which will in turn skew the results.

I will use the mileage reading on my GPS, thanks for the clarification.

The gps is nice but you can still use your Odom ...the key is finding out how much faster from a percentage point you are going. If you are going 5% faster than your actual speedo is saying...at the end of your tank just add 5% to your Odom reading. That does work and gets you as close as possible to the real mpg. The key is finding out exactly how much faster you are REALLY going. Do the test at 50 mph. If you are REALLY going 53 mph ...since it is half of 100...and you are going 53....but the speedo says 50...you are going 6% percent faster. Just find the percentage then after your tanks for mpg just add 6% to your total trip Odom.

50 is a good number and the GPS will give me a correlative speed and distance that I can compare.