mm5aho

My Q3 is more fuel efficient in the afternoons than the mornings.
I drive 12 miles to work. Quiet backroads, little traffic, single carriageway, slow windy country road. Average speeds 30-50mph. Start of journey is same altitude as end.
I set out about 0700, and it takes about 25-30 mins.
About 1730 I drive the reverse of this route.
Both ways engine starts from cold, no running during the day.

To work: 36-38 mpg
Going home 48-50mpg.

Only difference I can see is air temp is lower in the mornings.

Should air temp make this much difference to economy?

Jatmobil

Have you accounted for the tail wind on the way home?? ;-)

JK.....

Unless you observe and post the average speed and exact time and distance of each journey, it is hard to tell!

audidriver4ever

Perhaps in the Mornings there is more Damp in the air? Damp replaces partly air (imho).

Highpark

uphill one way? traffic worse that time of day?

mm5aho

The starting point and end point is each direction are at the same altitude, so on average neither direction is uphill from the other. (Clearly there are some hills in between, but average isn't up or down hill).

The journey is largely westward in the mornings, and eastwards in the afternoon, and the prevailing wind is from the west, so tailwind could have some impact on average. But of course, on any specific day this will vary.

The distance is 16 miles each way. That's not a lot to measure economy very well, but the "computer" displays is anyway. Resetting the average consumption figure at work for the return journey is how I get the consumption figure for the reverse journey.

Having now doen this for about a year, during which time air temp has been all over the place, and not cooler in the mornings, I think I can rule out temp differences.

Average speed is 31-35 mph, typical speed up to 50mph. Its a windy country road, so not motorway speeds.

Still a mystery.