"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

"Nick Finnigan" wrote in message
...
DervMan wrote:

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


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.

I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you can
conclude that Tesco has too much bio, and the premiums are better.

Maybe: but three runs isn't enough to be statistically significant. 40
runs, maybe...

--
The DervMan
www.dervman.com

DervMan wrote:

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


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.

I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you
can conclude that Tesco has too much bio, and the premiums are better.

"DervMan" wrote in message
...
"Nick Finnigan" wrote in message
...
DervMan wrote:

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


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.

I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you can
conclude that Tesco has too much bio, and the premiums are better.

Maybe: but three runs isn't enough to be statistically significant. 40
runs, maybe...



Looking at your figures, try averaging 100mph for a while, will save you a
fortune.

"Depresion" 127.0.0.1 wrote in message
news:TISdnbV0SrjNfrLVnZ2dnUVZ8h6dnZ2d@plusnet...

"DervMan" wrote in message
...
"Nick Finnigan" wrote in message
...
DervMan wrote:

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


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.

I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you
can conclude that Tesco has too much bio, and the premiums are better.

Maybe: but three runs isn't enough to be statistically significant. 40
runs, maybe...

Looking at your figures, try averaging 100mph for a while, will save you a
fortune.


Heh Might be possible; the 9-3 is quoted as being 121 to 126 mph,
depending on your source. Either way 125 is ~max power engine speed. I
suspect acceleration is woeful over ~80 or so.

--
The DervMan
www.dervman.com

DervMan wrote:
"Nick Finnigan" wrote in message
...

DervMan wrote:

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


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.

I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you can
conclude that Tesco has too much bio, and the premiums are better.


Maybe: but three runs isn't enough to be statistically significant. 40
runs, maybe...

If those 40 runs all come within 1% of 0.77 gallons/hour, and the BP
ordinary ones do too, but the premiums always come out within 1% of 0.74
gph then the 3 runs can be significant. (Tesco is OK on a closer look).

"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.

Maybe you're useing the aircon, or the fan more in the summer?

Wishful thinking perhaps

On 18 May, 08:38, "Depresion" 127.0.0.1 wrote:
"DervMan" wrote in message

...





"Nick Finnigan" wrote in message
...
DervMan wrote:

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

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.

I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you can
conclude that Tesco has too much bio, and the premiums are better.

Maybe: but three runs isn't enough to be statistically significant. *40
runs, maybe...

Looking at your figures, try averaging 100mph for a while, will save you a
fortune.

Slower average speed suggests more stop-start driving.

For the record, I've had a notable improvement in the MPG from my
Passat since the weather has warmed up, and this seems to have been
the case with most of the diesels I've had over the past few years.

I believe they have to blend diesel to a different formula to ensure
it doesn't solidify in colder weather so this might partly explain why
I've generally seen less MPG in winter time than in summer... although
the need for things like the lights / rear heated screen / heater fan
etc, to be on more in the winter months might be a factor as well.

--
JackH

wrote:
On 18 May, 08:38, "Depresion" 127.0.0.1 wrote:
"DervMan" wrote in message

...





"Nick Finnigan" wrote in message
...
DervMan wrote:
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
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.
I would look at you Shell Ordinary fills and see if they do support the
apparent trend that your mpg is proportional to your mph. And then you can
conclude that Tesco has too much bio, and the premiums are better.
Maybe: but three runs isn't enough to be statistically significant. 40
runs, maybe...
Looking at your figures, try averaging 100mph for a while, will save you a
fortune.

Slower average speed suggests more stop-start driving.

For the record, I've had a notable improvement in the MPG from my
Passat since the weather has warmed up, and this seems to have been
the case with most of the diesels I've had over the past few years.

I believe they have to blend diesel to a different formula to ensure
it doesn't solidify in colder weather so this might partly explain why
I've generally seen less MPG in winter time than in summer... although
the need for things like the lights / rear heated screen / heater fan
etc, to be on more in the winter months might be a factor as well.

--
JackH
Well, that's exactly what I've found before now.