Much confusion - VEL & MPG

[Dave H]

I went to visit a mate in Shropshire who is recovering, slowly, from a hip replacement.
His 7 year old 2.2 diesel auto Jag XF hadn't run for 6 weeks so I took him out for a spin.  Lovely car, so I asked him what MPG he got, 50 he replied. How much is the road tax, £145 he replied.
I thought, my little Jazz gets 45 mpg and the VEL is the same.
I came home and my daughter visited me in her 5 year old Citroen Grand Picaso manual diesel.
Same questions got the reply, 55mpg and £20 VEL
I think I'm driving the wrong car.

[Jocko]

It depends on whether you want to drive a diesel or not. With increasing sanctions against diesels, I don't know if I would want to buy a new one, but a cheap, secondhand one could be a savvy deal.
My brother has a gorgeous 14 plate, BMW320D X-Drive estate (or is it a tourer?), and it is big, smooth, extremely economical, and with its 8 speed auto box, a joy to drive. I just don't fancy owning a diesel.

[John A]

I had a diesel Qashqai on PCP before the Jazz, with the turbo it gave great acceleration and mpg. But the writing was on the wall when the trade in offer was less than the guaranteed future value, so off it went back to Nissan for them to make the loss. My 2016 CVT Jazz makes about the same mpg but nowhere near the same acceleration. There again I don't feel hostage to whatever the government decides to do with diesels and how clean they are / are not. As the VEL is against emissions, IIRC, the Qashqai was Euro 6 compliant, so about £30 a year, the sting in the tail is that the CVT version, also £30 a year and Euro 6 compliant gave out 18 times the emissions in real road driving compared to the tests VW so wonderfully proved how to beat. https://www.theguardian.com/environment/2017/may/26/extremely-polluting-nissan-and-renault-diesel-cars-still-on-sale-data-reveals     https://www.theguardian.com/environment/2019/jul/23/nissan-refuses-government-request-on-qashqai-emissions

[sparky Paul]

I replaced my car last year with a big diesel estate, 160bhp, easy 55-60mpg knocking about, and £30 tax. It eats miles on long drives, and you can hardly hear the engine.

Yes, there's a lot to go wrong, and you have to manage the DPF carefully if you don't do much motorway mileage, but it's saving me £1500 a year in tax and fuel from the big petrol MPV I had previously.

[peteo48]

It's really difficult to get diesel mpg out of a petrol. On the VEL my Mk3 was registered one day before the new rates came in on 1st April 2017 hence I pay £30 per annum. An incentive to keep it!

[John Ratsey]

I wonder how many people work out mpg from fuel into tank and miles travelled rather than rely on what the vehicle tells them (my experience with the Mk 3 Jazz was that it was 9% optimistic).

Diesel engines are more efficient and diesel fuel contains about 15% more energy per litre https://www.acea.be/news/article/differences-between-diesel-and-petrol. While it may produce less CO2 than petrol, the taxation has failed to take account of the other nasties flowing ot of the exhaust pipe. The motor industry downplayed that aspect which politicians were happy to accept until NGOs produced strong anti-diesel evidence.

Also, the shape of the Jazz, which helps provide the Tardis-like internal space, doesn't help with the aerodynamics so it's significantly more economical when not driven too quickly (hence the Land's End to John O'Groats on one fuel tank but driven at 40 mph).

[sparky Paul]

While it may produce less CO2 than petrol, the taxation has failed to take account of the other nasties flowing ot of the exhaust pipe. The motor industry downplayed that aspect which politicians were happy to accept until NGOs produced strong anti-diesel evidence.

I can understand the issues with particulates and NOx emissions in city centres, but the exhausts are not the only source of particulate matter. I agree that restricting diesels, especially older dirty ones, has to be sensible where the worst congestion exists.

That said, I live in a rural area, and for the past 20 years, I have lived next door to one of the biggest dirty polluters in Europe - a 2GW coal fired power station, which has been supplying everyone's electricity whilst pumping out tonnes of pollution, and ironically, base load electricity for charging 'green' electric cars.

[ColinS]

a 2GW coal fired power station, which has been supplying everyone's electricity whilst pumping out tonnes of pollution, and ironically, base load electricity for charging 'green' electric cars.

Yeah it's amazing how little one hears about that.

[peteo48]

I wonder how many people work out mpg from fuel into tank and miles travelled rather than rely on what the vehicle tells them (my experience with the Mk 3 Jazz was that it was 9% optimistic).

Diesel engines are more efficient and diesel fuel contains about 15% more energy per litre https://www.acea.be/news/article/differences-between-diesel-and-petrol. While it may produce less CO2 than petrol, the taxation has failed to take account of the other nasties flowing ot of the exhaust pipe. The motor industry downplayed that aspect which politicians were happy to accept until NGOs produced strong anti-diesel evidence.

Also, the shape of the Jazz, which helps provide the Tardis-like internal space, doesn't help with the aerodynamics so it's significantly more economical when not driven too quickly (hence the Land's End to John O'Groats on one fuel tank but driven at 40 mph).

I do "real" mpg via fuelly but you are spot on with the 9% over optimistic thing. I found that on both my Mk2 Jazzes. This one (the Mk3) seems a little bit more accurate but not much. Maybe 7% optimistic. Could be because it's an automatic?