[tmtalpey]

Just thought I'd pass along that once again the Spring effect is kicking in, my V50's average fuel economy is headed back toward 25. My 6MT AWD has averaged 22.5mpg since new (17K miles) and it swings from a little below in Winter, to well above in Spring. The seasonal effect is very noticeable!

I keep fuel and mileage stats on my Treo with an app called Automobil. (http://www.linkesoft.com/automobil/) There are others but I've used this one for a long time. The best tankful so far yielded 28mpg, the worst 18. In this graph, the green horizontal line is the overall average, the dark blue one is the rolling average, and the jaggy one the actual.

You can clearly see the break-in effect as the engine loosens up and the ECU decides it's ready. That little uptick was in April 2005, at about 4200 miles. Same thing happened on our XC90, but at about 3200.

Thought this data might be interesting to some.

Tom.

 

[tmtalpey]

Re: Ah Spring, when the mpg rises... (mullmann)

Quote, originally posted by mullmann »

No prizes for guessing whether I'm getting better or worse economy

By the way, have you ever asked your dealer to diagnose whether your oxygen sensors are working within margin, and/or checked for manfold air leaks? These are two things that can (greatly) affect mpg. The O2 sensor diagnostics are relatively easy for a dealer to perform.

Seven - yes, ethanol formulations will reduce mpg, because ethanol has less energy per unit of fuel volume. However, many factors affect the final result, and some cars don't change much at all. You'd need to track fairly carefully to tell.

Tom.

 

[tmtalpey]

Re: (fdisker)

Quote, originally posted by fdisker »

The onboard computer tells me my current MPG agerage is 27. Just curious as to how accurate it is.

Sorry to say your car is actually getting 16.2mpg.

Yep. Definitely.

This enthusiast's computer typically reads about 5-10% high. Right now, it's saying 24.8 while my recent tanks together yielded 23.3.

Tom.

 

[tmtalpey]

Re: (mullmann)

I don't bother. The mileage of a single tank is uninteresting, the long-term consumption is. The variations come out in the wash.

Tom.

 

[tmtalpey]

Re: (littlezipp)

The car has a "saddle" (two-chambered) tank with an additional internal reservoir ensuring the fuel pickup is properly submerged. If drained very low, it can take some time for all these nooks and crannies to fill. This is one reason why not to milk your tank. Doesn't hurt anything if you do, though.

Tom.