the 'Fuel Consumption " thread was accused of becoming diesel vs petrol.
I've got a diesel vs petrol question, but I thought I better start a new thread.
Now, I'm curious. We don't get ANY of the L322 diesel options here, so this is just for interest only. They are the mysterious unobtainium over here.
The LPG folk always quote the cost per mile, rather than mpg because LPG gets worse fuel economy than petrol, but is still cheaper to run. And cost per mile is what it all comes down to in the end.
So, diesel seem to have better fuel economy than petrols, but diesel costs more and there seems to be a (slight) added cost for maintenance.
Has anyone actually been able to calculate the cost per mile savings (as a percent) of diesel over petrol given the fuel and maintenance costs? I think it would be quite interesting. Folks could then determine their annual costs with both and see whether the extra purchase cost, or the scream of a Supercharger, or the more frequent visits to the fuel forecourt are worth it.

Thanks

Enjoy the ride , this should be enlightening  2008 MY Supercharged
Rimini Red / Jet
four zone climate
remote park heater
and no ugly kid windows.
magnus satis quod turpis satis

Too complex for me that one - as the purchase price is usually higher for the diesel engined car - but so is the residual value - so depends on the age and mileage of the vehicle when you buy and sell it - that part probably accounts for as much as the fuel price / efficiency difference.

Tax on fuel is another interesting one - in France, diesel is noticably cheaper than petrol - in the UK, the prices are closer, but petrol is more expensive - because the governments have decided to apply different taxes - that could also change in future.....

You also have to take into account a few points...
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Higher purchase price that obviously leads to a higher re sale value of the Derv models...

The easier to live with miles per tank of the Derv models...

Diesel on your hands whilst refuelling...

Smell of diesel engine fumes (although much improved, still there)
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And yes i have owned both... Out of choice i would now own a 5.0 if only they had the 8 speed in it! So i now drive the 4.4TDV8 as it has that dreamy 8sp gearbox (which swayed my decision in the end) That said, i think the 4.4TDV8 is on a par if not better to drive than a 4.2SC IMHO...

I drive an LPG and my car is in the bargain/lower end of car values. this is definitely different to newer models, (my third LPG rangie) mine was bought already LPG converted, for £5000 two or three years ago....another £1000-2000 might have got me a diesel, but at any time, i could have serious (residual value compared) expensive repairs due. on either models however weighing up all options, LPG was what i preferred to drive. lpg availability is good for me.
there are so many things to consider, not just the overall cost. -I maintain my cars myself, but i'm not a diesel expert....
On older cars especially, diesels are falling out of favour with new low-emission zones, roadtax is higher on newer cars.
there are many postings on this subject, that give one sentence opinions on their personal choice, but one should gather as much genuine info, like REAL cost per mile, NOT dashboard pixel MPG -and overall servicing, yearly etc, and make an educated decision, on what to buy.

and then go and buy the Black one just down the road, coz it just looks GORGEOUS!

If you do a lot of miles or pull heavy trailers then Diesel is best. They all give better MPG and generally speaking they give much greater torque and much lower down in the rev range, which is ideal for towing. This is the very reason you don't see Petrol powered lorries any more. Yes diesel fuel costs more, but if you do a lot of miles it's still cheaper per mile to use a diesel.

In some countries like the UK, the annual tax on them is lower because they emit less CO2.

However Diesels are generally more expensive to buy second hand, because of the better MPG. They normally have slightly shorter service intervals. Like for like engine parts and repairs are the same as a petrol engine, so for example a new turbo for a petrol engine is roughly the same as a new turbo for a diesel engine. However most petrol engines are normally aspirated whereas diesels are turbo charged, i think that will change in the coming years though as more manufacturers are turning to smaller capacity petrol engines with forced induction in order to reduce fuel consumption and emissions. But as it stands theoretically a diesel is more expensive to repair, as you can't for example get turbo failure on a NA petrol engine.



If however you only do a few miles, with the occasional long journey. Then a petrol engine makes more sense, especially when buying second hand. I mean there is little point paying £2000 more for a diesel engine if you're only going to save £1000 in the cost of fuel for the time you own the car. When you do the occasional long journey it's only going to add a few quid to the cost of the journey, so it's hardly worth worrying about.

Back say 30 years ago, it was easier to maintain a petrol engine yourself, i mean any fool can rebuild a carburetter, but it takes a lot more skill and specialist equipment to rebuild a diesel injection pump or injectors. These days though where both petrol and diesel are electronic fuel injection there isn't that much you can actually repair without specialist equipment anyway.


For me i pick up my 4.4 petrol Range Rover on monday. I chose petrol because the older TD6 lump isn't particularly good and i don't do many miles. Personally though i like the way diesels deliver their torque. Where as 20 years ago you could drive a diesel car and know you were driving a diesel car from the noise, even if the performance was the same. These days the NVH levels are basically the same and if the car has been looked after they don't chuck black smoke out the back when you boot them.

Obviously there are lots of factors to consider, depreciation, purchase price (you might get a real bargain), road tax etc. But as a general rule of thumb if you do a lot of mileage then a Diesel is the way to go, if you don't then Petrol wont cost you any more to run.

Nicely weighed up there Zirconblue,

We have run both petrol & diesel powered vehicles since the late 1970's. We bought two new VW Golfs in 1980..one petrol and the other 1.6 diesel. The difference was night & day in favour of the diesel with less than half the running costs of the petrol version. The petrol model was consistently in the workshop with niggly petrol problems, and eventually the engine calved before 100,000 miles, and was scrapped. The diesel version led a very hard life with several demanding drivers thrashing it to hell and back. It never gave mechanical trouble and was sold at 278,000 miles going strong for good money.

Diesel fuel here in Ireland is approximately 10 cents per litre cheaper, plus the added bonus for those who are VAT registered having the ability to reclaim 23% VAT off its price. Therefore, for the business user today in Ireland, Petrol costs st£4.65 per gallon and diesel costs st£3.48 per gallon.

The modern diesel is a fantastic piece of kit. EU emission systems are causing significant issues with their various systems stiffling modern engines, but this is affecting all types of engines.

The biggest problems I notice with modern vehicles is poor servicing & diagnosis. Every day I see modern diesel engines with EGR, turbo & injector issues, and speak to owners who have either never serviced the vehicle or did so at a bare minimum. Technicians follow laptops as if they perform some sort of voodoo on engines and magically fix them....but they don't and the technician ends up replacing many unnecessary parts until the problems are fixed.

We ran a Mercedes E320 cdi up to 480,000km. In that time, the engine required two injector copper rings and two cleanings of the inlet manifold and egr system. We sold it on and eventually it was close to 600,000km before the torque converter finally packed in

We have have tried running petrol cars now and then but quickly got rid of them as the running costs mounted up. However, I do think a petrol engine vehicle can be a viable proposition for certain low milage users and indeed the modern LPG conversion systems seem to perform well and make economic sense also. 2008 Range Rover TDV8 435,000kms
2015 Range Rover L405 SDV8 Autobiography


2008 Ford Focus1.6 tdci Titanium DPF deleted

That's probably a big part of the problem. Technicians these days aren't really trained mechanics, they're just fitters. Diagnostic laptops are great, but they're still a tool and only as good as the technician who's using it.

anyone had an lpg conversion?

Plenty - and there is a search function at the top of the page

..and we have a whole section dedicated to it... ... - .- -.




Y. O. L. O.
.

Just to chuck my 10 pence worth in - I have a 1999 LPG V8 Jaguar and my 2004 FF is a diesel - I had looked at LPG FF's but could not find the spec/colour I wanted so went for the one I have now as it was a reasonable price - now running costs - I don't have any hard and fast scientifically worked out figures as I don't do huge miles (mostly urban) on average my petrol jaguar cost me about £20 a week alternating between a fill of gas one week and petrol the next with about once a month needing to do both. the FF on the other hand costs me about £30 a week in diesel for roughly the same miles - the computer in the Jag shows an average of 13mpg and the FF 22mpg

What any of that means is irrelevant as I did not buy either vehicle for the economy - I bought them with my heart and because I liked them

Apart from cost, being a bit hard to make a good like for like comparison, there are a few factors for me that swayed me from a TDV8 to my current 5.0SC as cost is not a big issue for me (cheap fuel here ).

The TDV8 does have turbo and/or EGR issues (the one I initially bought had a turbo failure, hence my freezing feet) which the petrols don't have. The SC engines seem to be bullet proof (apart from poor Ryans 4.2 SC nightmare if I'm correct). The 6 speeds are the same in both cars until the beautiful 8 speed was put in of course (I do want to drive one some day). The later 6 speeds should have all issues ironed out that the earlier ones had (my 4.2 SC gearbox nightmare !).

Furthermore, I hate the smell of diesel (the dirty hands can be solved with gloves) and do like the smell of petrol (a bit). I also hate the sound of diesel engines, no matter how hard the engineers try to make them quiet, they always have the diesel sound even if it is very faint. I ride Japanese motorbikes because I love how smooth they are and so are the SC engines in FFRRs !!!

The range on the diesels vs. the SCs is not great and I don't like it that I'm filling up more but it is not that bad. Good time to get some snacks/drinks/coffee every few hours and stretching my (old) body, toilet stops (with our little one we have a stop every hour or so anyway). I put 300 liter LPG in my GMC and got a good range out of it (1000 kms or more) and would put an extra tank in the SCs if it was easy (spare wheel well anyone ?? ) or necessary (for my Africa overland trip I would most certainly add a fuel cell or two to the 4.2 or 5.0).

The emissions of diesels are supposedly worse than petrol emissions but hey, they are both quite bad for the environment and should be replaced by full EV soonest. I will dearly miss the sound of V8s, V12s (and 4 cyl motorbikes ) but that is the way things have to become.

I'm very very happy with my 5.0 SC and am glad the TDV8 didn't go through. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Emissions from a diesel are worse but only depending on context.

A diesel pumps out less co2 which means it has less impact on global warming. However they do put out more soot, which stains buildings and aggravates conditions like asthma.

Something we were taught in my forklift training is that diesel fumes aren't toxic, the fumes smell bad and will make you choke, but if you're fit and healthy they won't kill you like petrol/lpg fumes. (I can't say I ever put it to the test).

Both are very clean burning on modern engines but diesel will always put out more soot and petrol more carbon monoxide. But burning fossil fuels will always create emissions of some sort which aren't good in large quantities.

''diesel pumps out less co2''

er, wrong,



info, http://people.exeter.ac.uk/TWDavies/energy...0fuels.htm


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