Great mpg

[Splashalot]

Its probably less optimal combustion and more to do with air density causing drag...

Air is 20% more dense at 0C than at 30C... thats a lot of drag.

In fact, that probably almost aligns with the difference in fuel economy...

I don't doubt that for a second.  But it doesn't explain why my average MPG changes noticeably each year like a switch has been flicked - it's not a gradual transition.  I'm still going with the Winter and Summer maps.

[SRGTD]

Its probably less optimal combustion and more to do with air density causing drag...

Air is 20% more dense at 0C than at 30C... thats a lot of drag.

In fact, that probably almost aligns with the difference in fuel economy...

I don't doubt that for a second.  But it doesn't explain why my average MPG changes noticeably each year like a switch has been flicked - it's not a gradual transition.  I'm still going with the Winter and Summer maps.

Could it be due to different seasonality blends of petrol?

With diesel, it’s widely known that there are different summer and winter blends. In some countries the formulation of petrol changes depending on the season. If this also the case in the UK, then that might be the reason for the step change in mpg if that step change coincides with the switchover from one season’s fuel type / formulation to another.

[Exonian]

We need decent MPG’s at present, filled up with just under 50 litres yesterday at £141.9 (Tesco Momentum) 
What the hell is going on with fuel prices?

[king monkey]

£1.41. Wow. That’s crackers. If it goes over £1.50 I’ll just start pushing the car around.

[Woeisme]

We need decent MPG’s at present, filled up with just under 50 litres yesterday at £141.9 (Tesco Momentum) 
What the hell is going on with fuel prices?

Just under 3 Sterling a litre? That sounds way too much.

Unfortunately nobody sells high octane fuel here anymore so 95 will have to do.

[Yusee]

That’s cheaper than 10 years ago. I bet you’re earning more than you were then.

https://www.racfoundation.org/data/uk-pump-prices-over-time

[Woeisme]

£1.41. Wow. That’s crackers. If it goes over £1.50 I’ll just start pushing the car around.

I read it as it cost 141.90 pounds to fill up. Nearly fell off my chair..

[Splashalot]

Could it be due to different seasonality blends of petrol?


[/quote]

Of course!  That's probably it.  Now why didn't I think of that?  (Don't answer)

Edit:  Not only can I not think straight, seems I also can't quote other posts!

[SRGTD]

Could it be due to different seasonality blends of petrol?

Of course!  That's probably it.  Now why didn't I think of that?  (Don't answer)

Edit:  Not only can I not think straight, seems I also can't quote other posts!
[/quote]

 

[fredgroves]

From DEFRA:

The UK has a moderate climate and temperature variations between summer and winter are relatively small when compared with continental Europe. As a result, the need for additives to counteract the effects of changes in the physical environment on the properties of petrol is low, with changes in the Reid  Vapour  Pressure  (RVP)to meet  the  requirements  ofBS  EN  228  being  the  primary  driver ofseasonal differences in fuel composition.While winter and summer minimum and maximum values for RVP are specified within BS EN 228:2012, the range of values is sufficiently broad such that the transition from 'summer petrol' to ‘winter petrol’ can be managed using intermediate blends. The triggers that signal the transition from one blend to another  have  not  been  clearly identified  and  in  some  cases  are  driven  by  customer  requirements. However, the following provides a simplification for the transition dates:
•Summer: 1st June –31st August;
•Winter: 16th October –15th April
•Intermediate: 16th April –31st May and 1st September –15th October.