Petrol vs Diesel

geordie_ben

Skeksis wrote: »

I bought my first diesel back in March, more out of curiosity than anything. It's an R reg 406 1.9TD. I then started doing some research into running it on veg oil, which it has been quite happily for a couple of months, without any modding, basically none is needed on this model. I've been pleasantly surprised by it's performance for an old nearly 150k diesel!

My last batch of 'fuel' was on rollback at Asda, 66p/litre! :j

You should by a special filter and get it for free from fish and chips shops. they have to pay to get rid of the oil, if you're taking it for free i'm sure they'd keep you well stocked

flyingscotno1 wrote: »

It obviously depends. I bought a diesel as I do 35miles a day on weekdays minimum, plus weekday stuff all but 4 miles on motorways, so it made sens when there was no price difference.

yeah i'm kinda thinking the same

Quinny wrote: »

Roughly based on my 2ltr HDi, at £1.15 a litre, and 45mpg average, you'd get 172 miles for your £20.

cools

luap2411

Now not wishing to start off controversy here, but have a good think, consider how much you can save, and if this is your only reason for considering buying ?

Look at what it will cost to buy the car and what it's likely to cost when you sell it. Petrol will often win here, but check with parkers online for the car you want to buy. then look at the miles you will do and how much fuel you will save, including the difference per litre between the two fuels.

Also consider the side issues, tax, and repairs. Honest John suggests with new cars you have to do a heck of a mileage to recoup the additional cost of a diesel, often 100k plus miles. You can use some more creative fuels in a diesel, this is true, but not just any engine, hunt the web and find out if what your buying will run OK, generally the more modern the engine the less chance it will have of tolerating it. The ones that will normally run veg fuel or diy diesel tend to be a bit gutless anyway.

Not for everyone I know, but I bought my wife a 12 month old (last of the line) Vectra SRI last year, 2 grand cheaper than the diesel version, cheaper to service, fuel consumption 2 mpg (5.8%) less than my previous Passat TDI, fuel is typically 5p/litre cheaper (4.4%), its also quieter, and smoother (more linear) than lurchy turbo diesels, and doesn't stink inside when the back windows are open.

Now most cars are pretty reliable, but injected petrol engines are simpler and cheaper to fix if they go wrong than turbo diesels. Check the model you are thinking of buying and see if it has any party tricks and what they might cost, particularly for diesels look at dual mass flywheels, turbo, inter cooler, and EM sensors. Also bear in mind diesel engines tend to be heavier so front tyres, brakes and handling (if you are in to that) will all be impacted. Also check the Australian studies on what pollutants petrol and diesels kick out, not the 'cropped' European studies.

Th flip side is if you are doing serious mileage you should save money on the fuel bill, at motorway speed it will probably be quieter, less RPM, and you will probably visit fuel stations less !

I'm not saying don't buy a diesel far from it, but just understand why you want to buy one. If you like them great lots do, if you can really make a saving great, but be clear why you want one, and don't just assume they are cheaper to run because in many cases it's a big urban myth.

So time for a good think !

Quinny_2

The fact that the op only has around £2k to spend on a car isn't going to really affect any future sale on a massive scale, be it petrol or diesel.

And as an owner of a turbo diesel car, in the 5 years I've had it, other than sundry costs, ie oil, filters, tyres timing belt etc, it has cost me less than £500 in repairs. (Fuel tank pump, dual mass flywheel.) I've never had an intercooler go, nor a turbo and mine currently sits at 138k on the clock, and is still as sweet as a nut.

Also your difference in petrol/diesel pl is way off the mark at the moment, well certainly around our area anyhow. The difference at the moment at the Shell garage I use, is 1ppl with petrol the lower of the two.

And on the subject of exhaust smells, well I don't smell a thing when the rear windows are open, so I can't agree with your point there.

Flying-High_2

Quinny wrote: »

The 1.9 XUD engine will have no trouble running on veg, but the newer HDi engines, like mine will be killed if you ran it on veg.

As long as its a Bosch Pump and not the Lucas ones I forget which years they change.... Ive read of Lucas pumps being ran on Veg but read far more die of death. Bosch and all should be well.

Flying-High_2

Quinny wrote: »

Roughly based on my 2ltr HDi, at £1.15 a litre, and 45mpg average, you'd get 172 miles for your £20.

And just as a comparison to the Question petrol VS Diesel ...

I average 40mpg with my daily driver a 2.0 Vectra Sri petrol on a 60mile round trip to work. And for £20 @ £1.129 I'm currently paying the mileage works out at just shy of 156.

patman99

Quinny must be driving a Ford Focus. These are really good cars (apart from the dual mas flywheel requiring a replacement every 70k miles on pre-'55' models (unless you want to incur a £1000+ repair bill when they go)).

It is worth noting that to comply with current regs, all diesel contains at least 20% bio-diesel (recycled vegetable oil). It has to in order to meet govt guidelines. As for HDi engines, it is best to find a commercial biodiesel producer, as they will have a suitable blend especcially for such modern engines.

Funny when you think about it, but when diesel engines were originally invented (by an Englishman, who then made the error of showing his design to a thieving German), they were designed to run on vegetable oil (easier to obtain than 'heavy oil'), now we're looking at changing them back.

Rolandtheroadie

patman99 wrote: »

It is worth noting that to comply with current regs, all diesel contains at least 20% bio-diesel (recycled vegetable oil). It has to in order to meet govt guidelines. As for HDi engines, it is best to find a commercial biodiesel producer, as they will have a suitable blend especcially for such modern engines.

Last pump I looked at claimed 5% bio diesel.
Bio IS NOT recycled veg oil. It has been chemically altered.

I run my Corsa D on recycled veg oil. Even mixing it in the wifes common rail diesel to 20% would !!!! it. The wifes SHOULD however run on good quality B100.

Quinny_2

patman99 wrote: »

Quinny must be driving a Ford Focus. These are really good cars (apart from the dual mas flywheel requiring a replacement every 70k miles on pre-'55' models (unless you want to incur a £1000+ repair bill when they go)).

A 99 406 HDi as stated in my previous posting.

patman99

Didn't realise Peugeot used dual-mass flywheels as well. Mind you, Ford, Peugeot and Citreon share so many diesel engine components, it isn't a surprise.

There used to be a bio-diesel plant near me, but as they were in the middle of no-where, and spent nothing on advertising, they went bust.

luap2411

Hi again, firstly not wishing to stir up a hornets nest but I think there was mention of a Golf 02/52 plate as a benchmark for the OP.

According to Parkers the difference between 1600 petrol and diesel Golf (same spec & year), is about £500 (private buy - Good), difference between diesel & petrol here is about 5p/litre, if you keep the car for 3 years the difference in residual value between the two will be negligible. If you buy the car on HP at £3k you can expect to be paying about 10% plus interest. So you have to be recovering about £200 PA to make it financially worthwhile, other things being equal.

Assuming the 30 miles per day mentioned, and lets assume a bit extra at the weekend etc, this would be about 8000 miles PA. Assuming the diesel does 40 mpg and the petrol does 35 mpg the actual fuel benefit of diesel is £256-£235= £21 PA. Assume other things being equal and car was on HP, the nett gain would be -£162 PA. Lots of assumptions I know, but not unreasonable ones.

However if you did 30000 miles PA and got a 10mpg difference (nearly all motorway miles and quick engine warm ups) the benefit would be £205 PA, or with the initial higher purchase cost and interest a nett gain of £19 PA. These type of calculations are borne out by the AA, who pretty much reckon you need to be doing 100k plus miles in a diesel over its life to get a break even.

So why do you see lots of new diesels on the road ? Firstly many new cars originate from mainland Europe where diesel is significantly cheaper, sometimes 30% cheaper than petrol. The car manufacturers would like to push diesels for economies of scale. Most new cars in the UK are company registered, about 70%. Because the residual on a diesel is much higher that a petrol equiv, and with high mileage the diesel has a lower overall running cost (many used car buyers just automatically assume a diesel is massively cheaper than a modern low emission petrol engine without churning the numbers). It is attractive for the company car driver as well because the tax is lower. As the cars have 3 year plus warranties gearbox or turbo failure etc are not a concern of the fleet manager. These cars can make great second hand buys, but not in terms of massive fuel savings, just good, cheap well (?) maintained cars.

Bear in mind the 3 year old diesel is a much more complicated and intolerant machine than the nine year old Golf, so forget veg oil. You could home brew diesel, and this could be very cheap. But Google it, possibly risky for your engine (can kill the cat if you get it wrong), requires cash outlay for the gear, and will provide you with a nice time consuming hobby, do you value your time ?

This of course excludes any additional service and repairs. Many diesels will have more expensive parts e.g battery, brakes etc, and tend to be harder on parts like tyres, clutches, gearboxes, flywheels etc. Bear in mind the 02 plate Golf will typically have about 80-100k on the clock, so it won't be a spring chicken.

Looking longer term as more people move to diesels the demand for the fuel will continue to increase. Now crude oil splits out into various fixed constituents, diesel being one of them. As the demand for diesel increases there will be an excess of other constituents including petrol. The likely outcome for us is that whilst both will undoubtedly keep rising, the difference between the two will start to expand. remember 10 years ago when diesel was cheaper to buy than petrol, then came the swing to diesels...

So back to my original point, are you buying the Golf diesel to save money. The numbers say you won't. But are you buying because you like Golf diesels ? then great, good for you go ahead and ignore what anyone else including me thinks because it's your money, and your choice. Good luck which ever conclusion you come to.