Motorway fuel consumption

[Dr Jekyll]

How much benefit can be expected on a reasonably gentle long motorway run from using a diesel, as opposed to a 1.4 or 1.5 Tsi petrol? And what's the difference between a 1.6 or a 2.0 turbo diesel?
Relative is trying to choose between diesel or petrol Golf or possibly Octavia. Motorway economy is an issue, but is a bit wary of diesels. It would be interesting to see some examples from owners.

[Dr G]

Done both recently.

2016 2.0 TDI Yeti hovers very low 50s on the motorway.

2015 1.4TFSI CoD A1 Sportback did about 44 on the same run.

The 1.6 diesel does need a gentle right foot to extract decent economy; they can feel underpowered and a good many cars fitted with this engine only have a 5 speed box. Leaves you working the box a bit or being in an 'odd' gear (i.e. sit in 3rd at 30) or feeling like it's revving too high (bit noisy at ~.8 leptons).

...and purely for comparison 2016 manual S3 does 33 - typical morning traffic, bit of town, bit of motorway. Same drive in all of them. I reckon I'd squeak an extra 3-5MPG out of each if I drove deliberately for fuel economy.

[A900ss]

Dr G said:

Done both recently.

2016 2.0 TDI Yeti hovers very low 50s on the motorway.

2015 1.4TFSI CoD A1 Sportback did about 44 on the same run.

I think it's a little unfair to compare a brick like Yeti Vs an A1.

For example, my C220d at 70MPH will do 70MPG as it's a slippery thing through the air and also has very high gearing.

What is the annual mileage OP as a few extra MPG may not be that much of a benefit but if you're doing big mileage, it becomes more important.

[Dr Jekyll]

A900ss said:

I think it's a little unfair to compare a brick like Yeti Vs an A1.

For example, my C220d at 70MPH will do 70MPG as it's a slippery thing through the air and also has very high gearing.

What is the annual mileage OP as a few extra MPG may not be that much of a benefit but if you're doing big mileage, it becomes more important.

Annual mileage about 25,000. Also regular 200 mile return trips and refuelling after every 3rd trip instead of every 2nd would go down well.

Also, presumably the 70MPG is when you're actually doing 70. If you do a long run mainly motorway doing 70 when you can, but with roundabouts etc at each end, what's the journey average like?

Edited by Dr Jekyll on Friday 6th April 10:19

[A900ss]

Dr Jekyll said:

Also, presumably the 70MPG is when you're actually doing 70. If you do a long run mainly motorway doing 70 when you can, but with roundabouts etc at each end, what's the journey average like?

Edited by Dr Jekyll on Friday 6th April 10:19

Absolutely. The car averages circa 58mpg in summer and 54mpg in winter. All driving.

For 25k a year, I would go diesel. In fact, I just have! I do circa 30k a year and have recently ordered a 2.0 TDI Passat estate. So I have put my money where my mouth is.

I do very little city driving so am not concerned about any future tariffs for entering cities. Also, it's Euro 6 which should help.

I would also recommend a 2.0 over a 1.6 as bigger engines do tend to do closer to their claimed MPG at higher speeds.

Best of luck.

[va1o]

Not quite the same but I've been driving a 2015 TT 2.0 TFSI back to back with a 2017 A5 2.0 TDI 190 recently. There is only 5mpg difference between them on the motorway.