Petrol vs diesel

[grocer jack]

I guess that all new motorhomes are diesel powered, but when looking at older vehicle does one choose petrol or diesel and why?

 

[w1ntersun]

Diesels are sluggers. Ideal for pulling heavy loads at steady speeds with loads of low down torque with fairly good fuel consumption, long life ( mostly ).

 

Petrol is cheaper to repair and quieter but its the fuel consumption that kills them.

 

Richard

[Dave Newell]

w1ntersun - 2008-07-31 3:48 PM

 

Diesels are sluggers. Ideal for pulling heavy loads at steady speeds with loads of low down torque with fairly good fuel consumption, long life ( mostly ).

 

Petrol is cheaper to repair and quieter but its the fuel consumption that kills them.

 

Richard

 

Not necessarily. I run a 2.0 litre petrol powered Autohomes highwayman and generally get 23-24MPG cruising at 55MPH. A 2.5 diesel of the same vintage pulling the same body rarely gets better than 25MPG at similar cruising speeds and the difference is negligible when you compare the prices of the two fuels. Besides which petrol engined 'vans are not subject to the congestion charge yet whereas an older diesel powered unit will cost 3200 a day to enter the hallowed confines of the M25 car park!

 

D.

[enodreven]

Hi, Dave

 

I would assume you adopt a very good driving practice to obtain the 23/24 MPG and i would suspect that if YOU drove in a similar manner the diesel version i would be very surprised if you didn't achieve a better differential than just 1-2 mpg,

 

I can't remember ever obtaining the manufacturers MPG from a petrol car albeit i have nearly always exceeded the manufacturers MPG from a diesel variant ?

 

 

 

 

 

Dave Newell - 2008-07-31 4:45 PM

 

w1ntersun - 2008-07-31 3:48 PM

 

Diesels are sluggers. Ideal for pulling heavy loads at steady speeds with loads of low down torque with fairly good fuel consumption, long life ( mostly ).

 

Petrol is cheaper to repair and quieter but its the fuel consumption that kills them.

 

Richard

 

Not necessarily. I run a 2.0 litre petrol powered Autohomes highwayman and generally get 23-24MPG cruising at 55MPH. A 2.5 diesel of the same vintage pulling the same body rarely gets better than 25MPG at similar cruising speeds and the difference is negligible when you compare the prices of the two fuels. Besides which petrol engined 'vans are not subject to the congestion charge yet whereas an older diesel powered unit will cost 3200 a day to enter the hallowed confines of the M25 car park!

 

D.

[Mr. Grumpy]

We had a 2.5 td Swift 540 and always got between 27 & 30mpg @ 60mph depending on the amount of hills we had to climb. Our current van returns 30 to 33 mpg, a 10% decrease in fuel consumption. I don't think a 2lt petrol would do as well if you could get one. I have noticed in reviews of the new X250 series the average fuel consumption seems to be around 25mpg. I wonder what it is in the real world?

[Clive]

The calorific value of a litre of diesel is greater than that of a litre of petrol by a reasonable margin. Part of this advantage is absorbed by the increased cost of diesel, another part is absorbed by the increased cost of the diesel engine. But it will be a long time before you see HGV,s running on Petrol in Europe.

 

In a genuine "like for like" comparison the diesel still wins if your mileage is high or you keep vehicles for a long time.

 

Also diesel is a lubricant so engines normally last a lot longer if properly maintained.

 

C.

 

[enodreven]

Hi Clive

 

I note your point about the increased cost of diesel as a fuel, can you or anyone explain why diesel is cheaper in Europe than there Petrol and from what i can find the same level of taxation is applied to both fuels in the UK,

 

Clive - 2008-07-31 5:59 PM

 

The calorific value of a litre of diesel is greater than that of a litre of petrol by a reasonable margin. Part of this advantage is absorbed by the increased cost of diesel, another part is absorbed by the increased cost of the diesel engine. But it will be a long time before you see HGV,s running on Petrol in Europe.

 

In a genuine "like for like" comparison the diesel still wins if your mileage is high or you keep vehicles for a long time.

 

Also diesel is a lubricant so engines normally last a lot longer if properly maintained.

 

C.

[Guest Tracker]

Dave Newell's fuel consumption is very similar to my own experience of these two engines.

 

Modern diesels are better and we get about 30mpg from the 2.3jtd old model Ducato Tracker.

 

If you only cover a low mileage and mainly drive in the UK where petrol is significantly less expensive (I avoided the word cheaper!) than the rest of Europe I would suggest that the joy of a lower buying cost and pleasure of a quieter engine make much more sense than an older and coa**er diesel unit.

 

As with most things there is no right or wrong way to do it - just personal choice.

[Basil]

One thing for further consideration though, with a petrol engine you have the ability to fit an LPG kit which dramatically reduces the fuel cost, a possible slight improvement in MPG and better emissions, apparently without any downsides, some of these are becoming affordable as well. Pity you can't get the same result with a Deisel with LPG booster!

 

Bas

[Clive]

The price of fuel at the pumps has more to do with politics than anything else. Some countries actually subsidise the cost of fuel although most others tax it. But in those countries where fuel duty seems lower there is often an increased tax on the vehicle itself, both anually and at point of new purchase.

Also you need to look at the overall tax burden the average person pays in any country. What does not come from road fuel will come out of general taxation.

 

Currently us in the UK spend just over half our income on tax one way or another. Its how that compares to other countries which matters.

 

If you compare for example France to the UK then we don't come out too badly by comparison overall. They pay more basic tax than us and the annual vehicle tax for a diesel vehicle is greater than ours. But then again they have so many more killometres of roads to maintain in for the most part a sparcely populated country compared to the UK. And you pay through the nose for most of the motorways.

 

Politics OK

C.

 

[Randonneur]

Clive - 2008-07-31 11:17 PM

 

 

 

If you compare for example France to the UK then we don't come out too badly by comparison overall. They pay more basic tax than us and the annual vehicle tax for a diesel vehicle is greater than ours. But then again they have so many more killometres of roads to maintain in for the most part a sparcely populated country compared to the UK. And you pay through the nose for most of the motorways.

 

Politics OK

C.

 

There is no annual vehicle tax on private motor vehicles or motorhomes in France. There maybe on Heavy Goods Vehicles. The vehicle tax was abolished in 2000.

 

Martin

[Clive]

Well I'm Bug...d!

The last conversation I had with a Frenchman over vehicle tax he was moaning about how diesel vehicles were taxed so much more than Petrol, but then again derv was so much cheaper. But it was well before 2000.

 

Thanks for the update

C.

 

[Vernon B]

Basil - 2008-07-31 10:08 PM

 

One thing for further consideration though, with a petrol engine you have the ability to fit an LPG kit which dramatically reduces the fuel cost, a possible slight improvement in MPG and better emissions, apparently without any downsides, some of these are becoming affordable as well. Pity you can't get the same result with a Deisel with LPG booster!

 

Bas

 

Interesting, this came up in conversation with a non-motorhoming but well informed friend over the weekend. He'd carried out his own LPG conversion on a petrol vehicle a few years back and told me he was sure he'd seen kits offered for diesel engines recently.

 

V

[rupert123]

Vernon B - 2008-08-01 4:58 PM

 

Basil - 2008-07-31 10:08 PM

 

One thing for further consideration though, with a petrol engine you have the ability to fit an LPG kit which dramatically reduces the fuel cost, a possible slight improvement in MPG and better emissions, apparently without any downsides, some of these are becoming affordable as well. Pity you can't get the same result with a Deisel with LPG booster!

 

Bas

 

Interesting, this came up in conversation with a non-motorhoming but well informed friend over the weekend. He'd carried out his own LPG conversion on a petrol vehicle a few years back and told me he was sure he'd seen kits offered for diesel engines recently.

 

V

 

You have always been able to get an LPG kit for diesels, however it only feeds in a small percentage of LPG so no real advantage when you consider costs of installion. I have had two range Rover V8's converted to LPG and while I consided it worth while the sums are not as good as they used to be. You will in fact lose mpg, not gain it, between 10-20% added to the big differance in cost now between the fuels probably no longer worth while.

[Guest Tracker]

I doubt very much that an LPG conversion on an older Motorhome covering limited mileage would make much economic sense - and the poor old 2.0 petrol engines of that era really do not need to have their already limited power reduced!