"Chris Bartram" wrote in message
...
DervMan wrote:
"Chris Bartram" wrote in message
news
I've noticed a slight drop in MPG lately, and on a forum I read so have
several others with diesel cars, as has my brother-in-law. Normally I'd
expect slightly better summer MPG.

Has anyone else noticed anything similar?

Is there any connection with biodiesel in forecourt fuel? My usage
patterns haven't changed.

Sorry, nothing that is statistically evidence either way. My five and
ten run trend is still picking up from the winter just as I'd expect.

The brother-in-law reckons he's seen a difference between brands. I'll
keep monitoring it.

About the time I had my Ka crash I upgraded my PDA's car cost application
and it happens to track brand, location and type of fuel.

I don't believe that there's a difference although my data would appear to
be suggesting otherwise... it's too soon to tell either way.

The data shows the average mph because if I flatter one type of fuel - say
if I only bought BP Ultimate Diesel for longer than usual runs - you'd see
higher mpg and mph figures.

The data can't take into account the different winter / summer grades.
Suffice to say I've only filled up with Total over the winter.

And sorry for the format issues, this report is generated by my PDA...

Brand Type Fills MPG MPH
ASDA Supermarket, 3 fills, 50.2 mpg, 39.0 mph
BP Ordinary, 8 fills, 50.2 mpg, 38.9 mph
BP Premium, 6 fills, 51.0 mg, 38.1 mph
Shell Ordinary, 44 fills, 49.8 mpg, 37.9 mph (my control fuel, 'cos I use
Shell the most often)
Shell Premium, 8 fills, 49.7 mpg, 36.5 mph
Tesco Supermarket, 3 fills, 48.8 mpg, 37.3 mph
Total Ordinary, 3 fills, 47.4 mpg, 36.2 mph

Overall with 75 fills, 49.8 mpg and 37.8 mph, 43,195.6 miles, 714 days,
£3,928.21.

For Premium, that means BP Ultimate Diesel or Shell V-Power Diesel. The 9-3
is currently running on Total's premium diesel, Excellium. No data for this
just yet.

The data above might suggest that Shell V-Power Diesel is slow and thirsty.
It just means that over these tanks the Saab spent longer in the city.

BP Ultimate Diesel appears to be more economical if you believe that
returning 51.0 is statistically significant against 49.8. It isn't. I need
another few years worth of data first! ;-)

--
The DervMan
www.dervman.com