Now that I have 15 tanks behind me, I feel confident publishing some stats on the accuracy (or lack thereof) in the Nav trip computer display of MPG. Bottomline for me: the Nav reads 5% too optimistic (high).

<font color=blue>'04 G35S 5AT, Black Obsidian/Willow, Prem/Nav/Sat</font color=blue>

293952-MPG-NAV.gif

 

weird, i find my nav reading 1-2 mpg more pessimistic. Although i don't have stats to back it up.

04 G35C 6mt/aero kit/nav/premium

 

The nav tells you the MPG??? I thought it only played movies and playstation games.

I've never recalculated my mpg, just trusted the nav. Thanks for bringing me back to the real world.

Russ

Black 6MT Coupe
Jax, FL
G35Driver.com Business Cards

 

i keep finding my navi to calculate according to an 18 gallon tank. This leads to pessimistic averages for me as well.

odd.

 

should the coupe or the sedan get better mpG? my setup is in my comment at the bottom.... i get between 16 adn 18 mpg (depends on how i drive) I'm sure that if i drove a little bit more like i should i could get 20ish, but DAMN its fun take one to redline then to slap it in 2

2004 Black on Black g coupe 6spd.... aluminum pedals, clear corners, z tube, and pop charger. soon to have 19" volk gt-c's and PIAA xtreme whites in the clearance and corners
Houston Texas

 

Noremac,
How did you measure "actual" distance?
I have Coupe with 18 inch tires and tested, multiple times, using mile markers that odometer shows 4.5% less miles than actually driven. Assuming that NAV shows GPS miles - that's "actual".
Jerry

 

For my "actual" I use the odometer (with stock tires) and record the fuel from the pump meter. The odometer may be off slightly, but 5% would be excessive. If this is the case, then your speedometer is off the same amount!

And the Nav also uses the odometer for mileage, not GPS. You can confirm this by monitoring its trip meter: it matches the odometer exactly. That leaves the error in the Nav to come from its assessment of fuel metering. It seems to be reasonably precise (consistent) but not accurate (calibrated).

<font color=blue>'04 G35S 5AT, Black Obsidian/Willow, Prem/Nav/Sat</font color=blue>