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Diesel vs. Petrol Cars

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Aussiest

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Hi there,

I am currently considering a new car. What is the deal with diesel vs. petrol in terms of economy & performance? It's a 1.6 litre engine.

I live in the city, so does this factor in (heard diesel is better for long distance)?

To your knowledge, what is the availability of diesel fuel at petrol stations in the city and on the interstate highways (melbourne to sydney, melbourne to queensland)?

Thanks for your comments
 
A complex question on economics and performance. Economics? at times diesel is dearer and at times cheaper than petrol. Diesels can /do get better mileage but how many klms do you do to offset the higher initial purchase price and possibly increased service costs. Performance? diesels of a given size usually develop less Kwt's than petrol but they do develop impressive torque by virtue of a longer piston stroke. It's all 6's and 7's read some motoring tests, take some test drives. Diesel is readily available on major highways,thats what trucks run on, but keep some disposable plastic gloves for refuelling as diesel pumps can be oily.
 
Forget Diesel,

Go LPG,

I have run LPG for about 4years now and it has saved me thousands,

you burn about 20% more LPG because it's a lighter fuel, However it's less than half the price of petrol.

For example my last tank of gas was 50c per litre, add 20% = equals 60c. So it works out at 60c/litre compared to petrol $1.25/litre.

Diesel is more expensive than Petrol in Australia, But I think it lasts longer, but the saving won't be as big as LPG.
 
I can't go LPG because the car comes with diesel. Maybe i'll just continue my search until i find a petrol version.
 
is it a 4wd? . any towing? ,,,,,,,, if so diesel MUCH better . more power for size


diesel available on all highways ,95% of metro fuel stations



all depends on what vehicle and what you using it for OZ and hi
 
Tysonboss1 said:
Forget Diesel,

Go LPG,

I have run LPG for about 4years now and it has saved me thousands,

you burn about 20% more LPG because it's a lighter fuel, However it's less than half the price of petrol.

.
Click to expand...

Gas pfffttt

If you really wanna save money on gas, get one of these babies

 
Diesel engine: change the oil check as required, check the water , Air cleaner look for broken brackets and any damage and forget about it until next time.
 
a couple of fairly small matters

bowser rage...not as many diesel vs petrol bowsers, wait 10 mins while a couple of dicks in front fill their Landcruisers

cant rev high in most diesel engines. not so good for overtaking etc
 
Anyways, off topic again but LPG can be a great saving. Even in the north where LPG is about 70-80 cents a litre is is still cheaper. Ford offer an LPG only model with modified cam timing and valves. I could drive from Cairns to Mackay on one tank (75 or 80 litres) with about 50km spare.


cheers,
 
Mr J said:
Revs are irrelevant.
Click to expand...

I cannot agree, how are revs irrelevant if you want to overtake, in a manual car, commencing yr OT manouver at about 3500rpm and finishing at (say)5700rpm, without changing gear?

try that in a diesel

(most diesels redline below 5000rpm vs petrol 6000rpm, and their power and torque curve falls away at high rpm, although they are better at low rpm)

I acknowledge that some of the small new diesel engines are much improved in this respect


agree with Stan101, LPG is very economical, and green friendly, just dont run low on LPG in Canberra!
 

That's why it is important to test drive before you buy a diesel, adjust your driving so you spend most of your time around 1500-2000 rpm and you'll have plenty of 'go' when you need it. Pick a 2L mk5 diesel Golf and you can overtake pretty much anything on the highway in 5th gear safely, it has THAT MUCH torque more fun than a GTi

m.
 
marklar said:
Pick a 2L mk5 diesel Golf and you can overtake pretty much anything on the highway in 5th gear safely, it has THAT MUCH torque more fun than a GTi
m.
Click to expand...

My dad swears by those things.

Awg, i'm not a hoon. Just your normal average driver. Do you still think i would have trouble over-taking?

One of the other things that bothers me about a diesel engine is re-sale value / opportunities. I like to buy cars that i can re-sell very easily...

Thanks for your comments so far! I might take it out for a test drive this week...
 
I own a hyundai i30 diesel. Best car i've owned

Diesel is cheaper then petrol and should always be since it's cheaper to refine.

Diesel are great for overtaking since they have more torque

Diesel engines are better - last longer, less wear. Just look at the old 1980's Mercedes

Great towing capacity due to the torque
 
Dowdy said:
Diesel are great for overtaking since they have more torque
Click to expand...

Large torque alone does not make a fast accelerating machine. Depends on where that torque is in the rev range and what that rev range is. Torque can be compensated for with gearing to give the illusion of acceleration, but it's not..


cheers,
 
I've driven otherwise almost identical vehicles in petrol and diesel versions. This wasn't a test drive but regular use at work, so I've done a few k's.

Bottom line is that unless you do actually want a race car, forget petrol. You'll need about 30 - 40% more petrol to go the same distance, petrol engines are inherently less reliable than diesel and there's really no performance issue with modern diesels (assuming there's a turbo).

In terms of performance, a couple of examples from real world driving.

Standing start at bottom of steep hill. 4 litre petrol engine - floored it all the way and it just manages to reach the speed limit (50) by the top. 3 litre diesel - reaches 50 half way up and could easily break the speed limit. Vehicle was a utility with identical tray and very similar load on both occasions.

1.9 litre diesel auto - no problem accelerating 100 to 110 up hills on the highway with 3 passengers and luggage. Comparable petrol vehicles would manage to do it but not as easily.

So I'm a convert. Never driven a diesel until about 3 years ago but would be reluctant to buy anything else now. Better economy, around 30% less CO2 (I'm not a green, but why pollute if you don't have to?) and decent on-road performance with the modern ones.

Petrol? Well it's still the best fuel if you want outright acceleration. Or if you want to run a lawnmower. Diesel's a better option for just about anything else in my opinion.

Serious engines - trains, power stations, ships, submarines and so on are rarely (never?) petrol and there's good reasons for that. Too unreliable and too expensive to even consider it.

I've never driven an LPG car so can't comment on that. In theory though you'll use significantly more of it than with petrol (and somewhere around twice as much as with diesel) so there's not really that much running cost saving unless you live somewhere with cheap LPG.
 


The overtaking problem only comes about if you select vehicle that is either underpowered, (or low rev limit, which is less likely with the modern diesel engines)

My answer was more of a technical observation, that is that petrol engines have more Power, but usually comparable max torque, for the same displacement.

this is due to the lower rev limit of diesels.

diesels have a better torque curve at low revs, which males them nicer to drive in most conditions, ie low rev city driving.

If you select a powerful enough diesel, in a light enough car, as others have mentioned, you will have no driveability probs at all.

my main experience with diesels is in heavy older vehicles such as trucks and Toyota Hilux, these vehicles have low redline, and not good for overtaking.
Torque and power fall alarmingly at high revs, unlike a petrol

new cars mainly have these issues ironed out, as far as I know.

I would stand by my comment that under no circumstance would i prefer to overtake in a diesel engine of the same capacity as a petrol.

resale should not be a huge issue imo

big + for diesel is fuel efficiency, but if that is your main consideration, LPG is cheaper.

very good diesel engines are very expensive to purchase
 
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