Diesel vs Petrol

[Sammy]

Once I get my new ST-X (order placed last Nov, factory delay until approx Mar !) I will be long-distance touring with a van as well as local driving. Never having had a diesel before I am curious to know what are the advantages a diesel has over the petrol engine as well as any disadvantages. I note diesel fuel prices are now more than petrol. Thanks.

 

[KraftyPg]

It does all depend on how you drive in but in general you can expect better economy out of a diesel than a petrol. The sums I did before I brought mine were long and time consuming and for my circumstances petrol had to remain something like 32.3 cents cheaper than diesel for diesel to be less efficient. Of course all those figures are ideal world conditions but in practice the few times I've cared enough to compare the differences have been similar.

Power also makes a difference, for my personal preference I'd rather drag our 3 tonne trailer with the diesel than the petrol but once it's rolling the differences between my diesel Nav and the other petrol Prado is limited.

Apart from that the best thing about a diesel is that they make a different noise to petrols and new owners often freak out that the noise is too much where as seasoned diesel drivers just love it.

 

[Old.Tony]

I went through this same debate before I bought mine. Diesel won the battle, despite the often higher diesel prices.

Unladen - not towing or carrying much - the petrol vehicle will use around 15LPHK, whereas the diesel will use 10-12LPHK. That's significant, over long distances. The petrol will get a warning light at around 430km into a tank of fuel, the diesel will get 540km (at 12LPHK, it will get 650km at 10LPHK).

Towing, the differences are larger. We're getting 15s and 16s towing a double-axle full height van at 1.8T. The petrols will go over 20LPHK - your fuel warning light should light up around 320km.

Performance - the petrol vehicle is really, really zippy. It has buckets of power, and zips the car off the mark in no time at all. Surprisingly, though, the diesel can also perform well, but it needs to spool the turbo up - that does take some time. You press your foot on the pedal and can count off about a second and a half before the beast starts to roar.

Off-road - both vehicles are capable off-road unless it gets wet, at which point the petrol vehicle stops and the diesel just keeps on going.

Fuel Availability - some outback towns only carry diesel, they don't carry unleaded or if they do, you have to arrange it in advance.

Noise - the diesels without a doubt are noisier. The petrol version sounds like an ordinary car, whereas the diesel sounds like a small truck. There's no escaping that - although inside the cabin, you don't notice it after a while and really, that's what stereos are for!

Hope that helps.

 

[KraftyPg]

Not that it makes your comments any less valid Tony but the new fuel figures for the diesel claim 8.5 manual and 9.0 auto, while the petrol is cited at 13.6 manual and 14.0 auto. So despite those figures being ideal conditions the diesel is even more efficient than our 09's which were cited as being 10.5, seems they have dropped 1.5 LPH for the Auto STX by putting the 140KW in it.

 

[Old.Tony]

I'd love to get figures like that. I'm only just managing to get mid-10s now that 50,000km is approaching on the odometer. Talk about a protracted wear-in period!

Then again, mine is a little overweight, tipping the scales at 2500Kg empty (and they're 1980Kg when new, how'd I manage that?). There's a chance that, with the removal of the DPF pipe I might get even better mileage - but I'm pretty bloody happy with the 10's I am capable of now (highway cycle) and 12s for around the city.

 

[Foxbat]

New Diesel Economy

Hey Guy's I can vouch for the economy of the new STX 140KW engine. I regularly get 9.4 l per 100Klm driving too and from work average 70KPH in light traffic. If I drive like a wuss I get 8.8 and If I drive it like I stole it I get about the 12's. On a trip with a full size van I get about 14-15 at 90-100KPH. The best I've had was 8.6 from Bendigo to Melb. Mines an auto too.

 

[nismo4x4]

Diesel +1. better resale value, engine block should last longer than a petrol one. Personally I love the sound of diesel motors.

 

[Aussie Frontier]

Only real disadvantage to a Diesel is our lack of real standards on fuel.There are lots of horror stories of a bad load of fuel causing a heap of damage.
I did the math when I bought mine and 4 years ago the differences in fuel etc meant that without the higher and more frequent services it was going to take 8 years to break even cost wise.Now that was using the quoted figures from Nissan on economy and the avareage mileage of 30,000kms per year.I think from memory the price of diesel was 20cents a litre dearer in those days.
On the higway currently I get about the 11.3/100kms unladen and about 12.4 round town.
Still cheaper than a V8 and actually will outrun them if you try hard enough. But mines a 4x2 and we get better gears for economy than a 4x4

 

[Sammy]

Many thanks to you all for your frank and useful advice. I will obviously have to get used to the different noise of the diesel but feel happier about the power, economy and outback availability of diesel fuel. Does the lack of diesel fuel standards cause concern? Does the diesel (ST-X auto) have to be serviced more often than the petrol engine and are servicings more expensive for the diesel? Thanks again in advance.

 

[KraftyPg]

Lack of diesel standards is a concern to some degree but if you stick to the name brand outlets and stay away from Bio fuels you will rarely have any issues. A bad tank of diesel can happen as easily as a bad tank of unleaded (just ask all those Melbournites who got stuck with silicone in their unleaded) but if you stick to Shell, Catlex etc and avoid places like United (not all) and others who use blends of 20% you should be fine. I'm fairly sure any servo using more than 5% blended fuel must make it known at the pump so if you see the sign saying so it may be worth reconsidering your fueling options.

Diesel servicing is more expensive for the comparative kilometer service and under normal conditions they don't need to be serviced any more than every 10K.

 

[Old.Tony]

This Christmas just gone my wife and I went to Uluru via Broken Hill, Port Augusta and return via Port Augusta, Deniliquin, Jindabyne, Sydney. Stopped for fuel in many places, one notable isolated fuel supplier was Kings Creek Station. I expected that this place would have to have been the most likely source of bad fuel in the stations that I stopped at but surprisingly they were good (I do recommend them for fuel, and they're nice people too, but be prepared to pay about 40cpl more than city prices).

We had no problems with fuel at all. The stuff at Kings Creek Station might have had bio in it, it could have been premixed by the tanker driver (that happens) but the fuel was good and we got very decent economy from it.

As Krafty says, ANY fuel could be bad. It's the risk we take when we refuel somewhere. The alternative is to carry enough fuel to get past the tiny suppliers and make it all the way to the big stations with high turnover - not always possible, but having a preference of stopping at truck servos will probably work in your favour.