Fuel consumption report
 

I went to France for 3 days, just wanted to note down my fuel consumption for future reference.
Covered 1349km or 838.4 miles, used up 139l of fuel.
Thats 6.03 miles per litre or 27.4mpg. Worse than before.

The fuel figure was derived from fuel put in, full tank at start + 60l along the way minus remaining fuel which was 4l from VCDS but as I now know there are roughly another 7l in there when it reads 0. So estimated 11l remain in the tank.

As you have calculated that the mpg is lower than before, after a long trip abroad. My initial thought would be that France use a different fuel mix.
Do you know how it compares to UK? There could very well be a different percentage of biofuel or ethanol in the mix.

I usually buy fuel in Norway as it has better milage, compared to Sweden. That goes for petrol as well as diesel.

Interesting observation, I never thought about the fuel difference.
I only bought 60 litres in France, 90 litres I brought with me from the UK.
Could be a number of other factors, new exhaust, errors in my previous calculation.

You'll never get an accurate fuel consumption figure if you use "roughly" and "estimated" values. The only way to do it is to zero the miles before the trip when you fill the tank. Then keep filling the tank and setting the miles to zero, noting the miles each time. And the end of the trip, fill up and note the miles. I've been doing this on every tankful for years (I know I need to get out more!).

I second that +++
I keep a driver's journal since April 2001

edit: another advantage you will have is you can calculate the total cost per mile over time.
I discovered that my BMW 530D -99 in fact was basically as expensive to drive as my Jeep Grand Cherokee 5.2 -96. Despite the Jeep being twice as expensive on the fuel

That's exactly what I did. Filled the tank, zeroed the miles.
Then kept receipts of every fill up. Then VCDS'ed the litres remaining at the end of the trip. As per my first post.
The only error in the calculation, as I already said, is that we cant measure precisely the litres remaining when VCDS measuring block reads 0 litrs, but we know some fuel remains because when I filled the tank I only managed to put 87l back in. (I was not willing to fill the tank to full after the trip just to get a more accurate measure how many were left)

The problem arises is that VCDS will carry on reading 0l even if you use some of those 7l below zero.

So the error in my calculation is assuming that there are another 7litres below zero when VCDS reads 4l remaining.


Even this margin of error +/- 7l is not enough to account for my previous best mileage, which was 581 miles with VCDS reading 1 litre remaining.
But those were different roads than the trip to France, that could explain some of the difference.

Alot of French fuel is E10 these days and this IS enough to affect fuel consumption for the worse.

I understand that the actual brews vary over the year too.

Nick

I filled 24l with BP 97 and 36l with Shell Vpower, those should not vary too much even in France surely?
I still think its to do with the exhaust, especially considering original exhaust was partially blocked with broken cat.