Petrol, Diesel or Turbo diesel ?

djh

I folks,

following the threads here there's sometimes mention of one of Petrol, Diesel or Turbo diesel engines being better/more economical. But over certain distances etc.

Just wondering if I were to look at a diesel car how many miles a year would I need to put in to make it worth the extra outlay? Also, would the journey time/distances need to be over a certain amount to get the benefits? Would a turbo be a factor in all that?

I know it's difficult to answer such general questions and that it all depends on the specific make/model/engine/year, but any rules of thumb that you could give would be appreciated to give me a starting point.

Cheers,
DeeJay.

sentient_6

You need to factor in what it's costing you to you buy the new car.

You could upgrade fom a random petrol to a say a 2L diesel & put in say 3000 grand cash along with the old car. But you need to work out through the fuel consumption & the price difference now in diesel when you'll see that 3000 back in fuel savings based on your yearly millage.

You'll find it hard to find a modern, non turbo diesel me thinks.

MugMugs

VW not still do SDI Polo and Golfs?

sentient_6

I'll give you an example from a thread a guy had a few weeks ago that i didnt bother to post back in.

Guy claimed he was doing 32000km's a year in a ~02 1.6 A4. According to parkers it should do roughly 7.8 L/100km's. That means you'd burn 2496 litres of fuel in a year @ about what, €1.47 a litre? = € 3669 a year on petrol.

He was wondering about changing to a TDI golf. Again according to parkers should do 5.4 L/100km(bit generous if you ask me). Therefore over your 32000km's you'd only now burn 1728 L of diesel @ about €1.39 = €2401.

That's a difference of €1268 in the first year.

Thats with resonably high millage. Somebody doing alot less millage that could spend years trying to see back whatever they potentially put into getting the car in the first place.

See what your spending now over your millage, & work out what you could be spending, & see then if its worth it.

SomeGuyCalledMi

sentient_6 wrote: »

I'll give you an example from a thread a guy had a few weeks ago that i didnt bother to post back in.

Guy claimed he was doing 32000km's a year in a ~02 1.6 A4. According to parkers it should do roughly 7.8 L/100km's. That means you'd burn 2496 litres of fuel in a year @ about what, €1.47 a litre? = € 3669 a year on petrol.

He was wondering about changing to a TDI golf. Again according to parkers should do 5.4 L/100km(bit generous if you ask me). Therefore over your 32000km's you'd only now burn 1728 L of diesel @ about €1.39 = €2401.

That's a difference of €1268 in the first year.

Thats with resonably high millage. Somebody doing alot less millage that could spend years trying to see back whatever they potentially put into getting the car in the first place.

See what your spending now over your millage, & work out what you could be spending, & see then if its worth it.

Excellent example but a diesel might depreciate more slowly which could make up for the initial outlay.

sentient_6

SomeGuyCalledMi wrote: »

Excellent example but a diesel might depreciate more slowly which could make up for the initial outlay.

Oh i agree there's alot of other factors. There's potentially more expensive repairs that could pop up on your diesel also though like the dreaded DMF & DPF(which mightn't be an issue at all depending on what type of millage your doing).

djh

Cheers for the info folks.
Think I can get my head around that now. The savings from fuel cost have to be more than the extra cost of the car over its life. :-)

What are DMF & DPF?

Ardennes1944

theyre basically 2 of many things in modern diesels that make them so economical but as with most things theres a catch, if your driving mostly in town and traffic they can get clogged and can cost 800-1000+ to replace

MugMugs

MugMugs wrote: »

VW not still do SDI Polo and Golfs?

I'd like to think not.

sentient_6

djh wrote: »

What are DMF & DPF?

DMF is a dual mass flywheel, which is a componant of the clutch, think of it as a damper to absorb the extra vibrations of a diesel engine. Due to its mechanical make up its a ware & tear item. One of the problems is to change it, the clutch has to come out & is a days work. So when it comes to getting your clutch changed most mechanics would reccommend changing the fly wheel while your in there, even if its still fine, to save yourself the labour cost to have to do it all again further down the line. I'm in this boat soon & the flywheel is adding about €300 to my clutch change. At the same time, people get hysterical about it cos there where alot of cases of it failing prematurely on some cars. €300 in terms of your overall spending of a car isn't a whole lot in all fairness. If it doesnt fail early, & you change it as a precaution when your clutch goes.

DPF is a diesel particle filter. It works by storing up diesel particles from the exhaust & then burning them off every now & then, like on a long motorway run. If one only does small runs in & out of town or whatever then the DPF never gets the chance to heat up & do its thing. If you do plan on doing half decent drives every now & then then this isn't an issue.

If your type of driving would minimise a DPF issue, then i wouldn't rule out a diesel just cos of the DMF.

Greyfoot

turbo on a petrol engine...

For Forks Sake

MugMugs wrote: »

VW not still do SDI Polo and Golfs?

No. Thank f*ck.

Had a Golf SDi as a company car, walking would have been preferable.

djh

Cheers folks, I've got my head around it now and will have a few extra things to look at in the service history!

Another quick question though,
how long of a run would be needed to clean out the accumulated particles in the diesel particle filter? Would you need to do it ever day/week/month?

pat127

djh wrote: »

Cheers folks, I've got my head around it now and will have a few extra things to look at in the service history!

Another quick question though,
how long of a run would be needed to clean out the accumulated particles in the diesel particle filter? Would you need to do it ever day/week/month?

Not an expert, but as one hasn't replied I'll give you my tuppence worth. No direct answer to your question. Some cars rely on 'passive regeneration' which means that the particulates burn off themselves when the manifold gets hot enough. The Skoda Superb for example has a warning light which tells you that you'd need to blast down the m-way until the light goes off.

OTOH according to a dealer I spoke to, the Focus doesn't have a warning light leaving you to decide, dependent on your type of usage, whether the car needs a good run. The Kia Cee'd 1.6D for instance has 'active regeneration' where the burn is triggered by the control electronics every 300 miles or so. It can be spotted apparently if you are watching the instantaneous consumption meter which drops markedly. BTW No one in the dealerships in my experience tells you any of this. It pays to ask them.

2 useful sites when you are doing your sums:-

Real-world consumption figures (the ones supplied by the manufacturers are usually overstated) http://www.honestjohn.co.uk/realmpg/

Petrol or diesel fuel costs calculator
http://www.which.co.uk/cars/driving/driver-tools/petrol-vs-diesel/petrol-and-diesel-fuel-costs/

Again my personal opinion, I don't much like the way the modern small 1.4 and 1.6 TDs work. Too much gear-changing to keep them rolling and lots of use of the turbo.

A point to watch - very few petrols being soldat present I think, which will almost certainly reduce the residuals. Manufacturers trying to improve the efficiency/consumption though, e.g. VW's small-capacity, low-consumption petrols (1.2 and 1.4Si).

Good luck!

djh

Cheers Pat,
appreciate the info!

johnos1984

You need a nice reliable 1.6D VW

GaryMunster

For Forks Sake wrote: »

No. Thank f*ck.

Had a Golf SDi as a company car, walking would have been preferable.

hilariously slow

EPM

johnos1984 wrote: »

You need a nice reliable 1.6D VW

China import?

johnos1984

EPM wrote: »

China import?

China market only but if you could import one the Skanger lads would love ya

djh

Wow! That reminds me of the old school Jetta, or the VW Derby (showing my age!)

djh

djh wrote: »

Wow! That reminds me of the old school Jetta, or the VW Derby (showing my age!)

it is an ole jetta :pac: