gas mileage: discrepancy between actual vs trip computer

Reply Subscribe

Thread Tools

Search this Thread

Dec 29, 2009 | 07:02 PM

knutcracker

Thread Starter

AudiWorld Member

Joined: Sep 2002

Posts: 112

Likes: 0

gas mileage: discrepancy between actual vs trip computer

so, my trip computer tells me i'm averageng 18.5mpg, but with some calculation, i found out that i am actually getting 16.5 mpg. i use Shell V-Power (it's 93oct, i think). i also have a flashed APR chip, so that might or might calculate differently. does anyone have this issue? what's going on here?

Dec 29, 2009 | 07:27 PM

donromani

AudiWorld Senior Member

Joined: Apr 2009

Posts: 1,901

Likes: 0

I'm pretty sure this is just a problem of stacked tolerances. That is, your trip computer is making calculations based on sensor data (requested fuel volume, vehicle speed) and you're making calculations based on (I assume) the readout from the gas station and the vehicle tach. Both are bound to be off a little, so your margin of error is just adding up and making the discrepancy look larger than it actually is.

IMO, nothing to worry about.

Jan 7, 2010 | 12:15 PM

bcr84urq

AudiWorld Member

Joined: Feb 2006

Posts: 289

Likes: 0

My computer always reads about 2-3 mpg higher than actual. Lame but not the end of the world. At 2 mpg high - that is 10% - pretty big variance if you ask me.....

Brandon
'84 ur-quattro 20Vt
'01.5 S4