Petrol V Diesel

balsingh

I dirve both Diesels and Petrols. I have to say that diesels have come a long way .... but dont write off recent petrol engines either. The latest petrol engines are also very frugal compared to a few years ago. Its not like say 5-10 years ago where a diesel would give almost 10mpg more on average .... these days, that gap seems to be getting smaller and with the cost of diesel being around 4p/litre more, the sensible choice isn't always the diesel.

MrSmartprice

I've driven diesels for 20 years, so they've improved a hell of a lot in that time. Then I did huge mileage so it was a no-brainer. Now I do less, but enough to justify a diesel.

If you do, say, 12k a year, and plan on keeping the car for a few years, it's certainly better to run a diesel, and there are plenty to choose from.

What really annoys me is that diesel is priced higher than petrol. This is ludicrous. In the past it has usually been a bit cheaper, and hopefully this will return. But compare the situation to any other country. I don't know anywhere where the diesel is even close to the petrol price. In Europe it varies between about 50% and 80% of petrol prices. So the economics of diesels are far more clearcut abroad.

superscotsman

The main trap with diesels as opposed to petrols is that if money is a bit tight, you can delay a service on a petrol car and get away with it. On diesels this is not such a good idea.
The best thing to do is try a diesel car if you want to. You might get to like it. I personally don't, but that's just a matter of habit.

Cardew

tomstickland wrote:

Only £200 per year. Why's it so low?

Well a calculation assuming 35mpg overall for petrol and 20% better for the diesel is 42mpg.

12,000 @ 35mpg = 343 gallons = 1,557 litres @ 86p = £1,339

12,000 @ 42mpg = 286 gallons = 1,297 litres @90p = £1,167

That is a difference of only £172

Assume the diesel is 30% more economical(unlikely?) and the saving is £261

What figures would you feel are more representative?

tomstickland

I wasn't really questioning the results, I was just surprised at it being that close.

So, if we say that Diesel is 20% more efficient than petrol, but diesel costs 5% more, the difference is about 15% in favour of Diesel. Or using the proper numbers of 20% and 90/86 the overall ratio is 0.87. ie:13% saving for Diesel. Say on average you fill up each week with £40 of petrol then that's £2000 pa (and represents about 16K miles pa). Moving to Diesel to save 13% of £2K would be £260. All rough and ready.

jjames_3

Diesel engines have traditionally been very reliable and long-lived.

However, recent designs have at times been anything but. There have been a spate of expensive turbo failures across a number of manufacturers, and some mechanics are recommending that owners get rid of common-rail diesel cars once they're out of warranty.

Given the extra initial price cost of a diesel car, and the rather small difference in cost of ownership mentioned above, many diesels need to be used for at least 15-20000 miles a year just to break even against an equivalent petrol car. And that's before you consider the amazing deals to be had on a lot of 1.8 petrol Mondeo-class vehicles which just aren't shifting as people want the diesel.

When, for example, a brand-new 1.8 Nissan Primera can be had for £8000 a couple of months back, and the 2.2 diesel stuck fast at £15000, you need to do an awful lot of motorway miles to make that saving back up. Granted the 1.8 won't perform anywhere near as well as the diesel, but look at the savings.

tomstickland

A friend had an asthmatic 1.7 TD Astra Estate, and due to the lack of power he just drove with his foot wedged into the carpet all the time. The mpg was not very good as a result. I'm not implying any sort of anti-Diesel result here, just back to the old thing that small/low power engines are not more efficient if driven hard.

balsingh

Diesels perform best when cruising at a constant speed hence being great for reps going and down motorways. For day to day drivign around town etc. petrol engines are more flexible. There is also a lot more MPG variance depending on how carefully or hard you drive a diesel. The variance isn't as much for petrol.

goldentouch

We had a saab 93 convertible petrol 2.0 lpt and have recently traded in for a saab 93 diesel 1.9 tdi. I thought the first one was powerful but this one is amazing. Acceleration between 30 - 60 in 3 seconds. Great fun. :T

MrSmartprice

The Vauxhall 1.7D engine was notorious as one of the poorest of the everyday diesels. It was slow, dirty, smelly, and showed little difference to the petrol engine for mpg. I test drove one years ago and that was enough. It was almost as bad as the 2.0D Perkins they used to put in the Montego. :eek:

The only unreliable diesel I have had in 20 years was the Ford 1.8 Turbodiesel. The turbo blew under warranty, and loads of other things failed on it too. I ditched it as soon as the warranty expired. Other Ford diesels were fine.

I am now on my 4th Citroen diesel and have never had any trouble with any of them, having covered about 300k miles altogether.