Petrol vs Diesel: A 10 year urban running cost comparison

[rob_macca67]

At a difference of only $300/yr and then not having to worry that much about a dose of dirty fuel or electronic chips; EGR clogging.... the Petrol is looking better and better these days

Hey all,

As some are interested, I've also done some calculations for "total" driving, which includes bush trips and towing etc.

I'm using the economy figures from Rob and JGD, which are 12.4l/100km for diesel and 15.2l/100km for petrol.

The figures for average fuel cost from Rob and JGD of $1.52/l for diesel and $1.25/l for petrol are a bit off compared to the national average. It is likely that the national average I have used from AIP is statistically more representative of city costs at $1.45/l for diesel and $1.40 for petrol (over the 10 year period). Robs figure of $1.52 makes sense as it includes more expensive fuel at remote locations that are likely not included in the national average. The figure of $1.25 for petrol from JGD is very low compared to the national average and doesn't make sense if it includes remote trips and towing etc.

As such, I've run the numbers again for "total" driving using the national average from AIP.

The total costs looks like this over the 10 year period;



This plot shows that petrol is still more expensive than diesel over the 10 year period, with total fuel costs of $33146 for petrol, and $28031 for diesel.

The difference is $5115, or $511.50/year.

Assuming the $100/year cheaper service schedule for the petrol (from http://www.carservice.com.au/car-ser...auto-09_05-09/) brings the difference down to $411.50/year.

Factoring in at least x1 injector change on the diesel at a $2000 cost distributed as $200/year over 10 years brings the difference down to $311.50/year.

This analysis suggests that "total" driving is going to be around $300/year more for the petrol, or around $26/month.

I know some will want to argue about the fuel economy figures, so go for it, but I think this analysis shows that the argument of petrol vs diesel doesn't really exist, at least for the Prado!

Another point to consider in this debate that no longer appears valid is that diesel gets higher resale value compared to petrol because it's cheaper to run. That argument is over!

Best

Mark

[Whitey]

Hey,

The calculations are for ULP 91.

You can run 91, 95 or 98 in the petrol.

Best

Mark

[ozimacca]

Hi Whitey,

Very interesting thread, thanks for your data.

I have a diesel so I have no idea but does the petrol version use 91, 95 or 98 octane and which octane have you used for your figures ?

For those with diesels I have noticed that mine definitely runs better on BP Ultimate and fortunately around here it is the same price as Caltex Vortex Diesel, which my 150 hates !

[Whitey]

Hey all,

As some are interested, I've also done some calculations for "total" driving, which includes bush trips and towing etc.

I'm using the economy figures from Rob and JGD, which are 12.4l/100km for diesel and 15.2l/100km for petrol.

The figures for average fuel cost from Rob and JGD of $1.52/l for diesel and $1.25/l for petrol are a bit off compared to the national average. It is likely that the national average I have used from AIP is statistically more representative of city costs at $1.45/l for diesel and $1.40 for petrol (over the 10 year period). Robs figure of $1.52 makes sense as it includes more expensive fuel at remote locations that are likely not included in the national average. The figure of $1.25 for petrol from JGD is very low compared to the national average and doesn't make sense if it includes remote trips and towing etc.

As such, I've run the numbers again for "total" driving using the national average from AIP.

The total costs looks like this over the 10 year period;



This plot shows that petrol is still more expensive than diesel over the 10 year period, with total fuel costs of $33146 for petrol, and $28031 for diesel.

The difference is $5115, or $511.50/year.

Assuming the $100/year cheaper service schedule for the petrol (from http://www.carservice.com.au/car-ser...auto-09_05-09/) brings the difference down to $411.50/year.

Factoring in at least x1 injector change on the diesel at a $2000 cost distributed as $200/year over 10 years brings the difference down to $311.50/year.

This analysis suggests that "total" driving is going to be around $300/year more for the petrol, or around $26/month.

I know some will want to argue about the fuel economy figures, so go for it, but I think this analysis shows that the argument of petrol vs diesel doesn't really exist, at least for the Prado!

Another point to consider in this debate that no longer appears valid is that diesel gets higher resale value compared to petrol because it's cheaper to run. That argument is over!

Best

Mark

[Whitey]

I agree, too high for petrol consumption. I have a 2014 150 GXL V6 with TJM bar, roof rack, awning, pvc rod holder, shovel, dual battery, 4mm underbody plates, recovery points, compressor, fridge etc and around the city I get 14.5 L/100Km.

Hey,

That is impressive economy for urban driving! I don't think the 120 will get near that with urban driving, even if I baby mine I still struggle to get below 17l/100km (on my scangauge).

Best

Mark

[maulbeagle]

I agree, too high for petrol consumption. I have a 2014 150 GXL V6 with TJM bar, roof rack, awning, pvc rod holder, shovel, dual battery, 4mm underbody plates, recovery points, compressor, fridge etc and around the city I get 14.5 L/100Km.

[Whitey]

17L/100h for the petrol is too high for average users. Somewhere between 14L and 16L seems a good average from posts in the V6 consumption thread.

I've kept accurate fuel figures since 2007 (8 years) and over the life of the car since then have averaged 15.2L/100k, including all trips/towing/etc.

Average cost of petrol over that same period (8 years) is $1.25/L.

All the gear stays on/in when around town - including the bar, lift, tyres, winch, batteries, drawers, cage, etc. Only the roof tray comes off.

Motorway/highway it's down to high 13's - even with all the gear (used to be able to get high 12's with nothing bolted on).

Hey JGD,

The calculations I've shown are for an "urban" setting, and don't reflect total lifetime driving, where the cost of fuel can vary dramatically depending on where you are driving, eg, well over $2/litre in remote areas.

Around the city in an urban setting with a mix of driving conditions, I regularly get somewhere in between 17-18litres/100km for my V6, which is 2.3 tonnes with most of my gear on it, arb bar, built in rear cargo area with fridge, battery etc. I am a lead foot though!

Cruising on the highway, I'll get 11-12litres/100km.

I'm happy to do lifetime comparisons if you have accurate records, but you'll need your service costs as well for it to be meaningful. How many km have you driven in that 8 years?

Best

Mark

[rob_macca67]

Well, $500/yr to me is not that great of a difference and if I have to choose between NEW Petrol vs NEW Diesel (especially if it has a DPF), then I would be leaning towards a Petrol these days...... If you're constantly towing, I'd have to think really hard though. I just think that with all the advancement in Diesel performance, diesels seem to be losing their reliability/durability heritage....

Hey Rob,

The $500/year is an all inclusive figure (service schedule +fuel), that incorporates x2 injector changes at $2000/injector change.

If you only did x1 injector change in the 156000km 10 year period, then you save $2000, or $200/year, which would make the savings go up to $700/year for the diesel.

All depends on how often you need/want to change your injectors.

Best

Mark

I was thinking the same thing myself.... After talking to a few Petrol owners, 17ltrs/100kms seemed a tad high and the figures that u produced seem more realistic..... I'm not up to date on what can go wrong with the later model 4ltr V6 engines (talking about the ones in the 150's), but I think the V6 is looking more and more viable if driven sensibly as u don't have to worry about installing a Chip for better performance; EGR's aren't the problem they are in a Diesel; no DPF filters to worry about, etc, etc..... The one thing that I want and look for in a car is fuel range for remote travelling & that's why I initially purchased a Diesel, but with a LR tank, this is less of a problem in a petrol as u should be able to get 1000kms even when crossing deserts, etc....

just my thoughts though.....

17L/100h for the petrol is too high for average users. Somewhere between 14L and 16L seems a good average from posts in the V6 consumption thread.

I've kept accurate fuel figures since 2007 (8 years) and over the life of the car since then have averaged 15.2L/100k, including all trips/towing/etc.

Average cost of petrol over that same period (8 years) is $1.25/L.

All the gear stays on/in when around town - including the bar, lift, tyres, winch, batteries, drawers, cage, etc. Only the roof tray comes off.

Motorway/highway it's down to high 13's - even with all the gear (used to be able to get high 12's with nothing bolted on).

[lang01]

good to know

[JGD]

For the diesel I’ve used 11litres/100km and 17litres/100km for the petrol.

17L/100h for the petrol is too high for average users. Somewhere between 14L and 16L seems a good average from posts in the V6 consumption thread.

I've kept accurate fuel figures since 2007 (8 years) and over the life of the car since then have averaged 15.2L/100k, including all trips/towing/etc.

Average cost of petrol over that same period (8 years) is $1.25/L.

All the gear stays on/in when around town - including the bar, lift, tyres, winch, batteries, drawers, cage, etc. Only the roof tray comes off.

Motorway/highway it's down to high 13's - even with all the gear (used to be able to get high 12's with nothing bolted on).

[Whitey]

Injectors commonly ok average up to 150k. Many with 200-300k but lets not go there.

They need to be replaced every 5-6 years or 120k, whichever comes first.
$2k BDG Injectors fitted. Incl piston inspection, valve clearance check & compression test.
Most people do 120k+ in 5 years, unless its parked & low Klm's vehicle.

Hey ####,

For the purposes of this "urban" model with 300km/week driving, this is 156000km over 10 years, so as I said to Rob above, if we include only x1 injector change according to your 150000km interval, then the diesel owner saves $2000, and distributing that back over the 10 year period means the diesel saves $700/year compared to the petrol.

Still pretty close I reckon at $700/year.

Best

Mark

[Whitey]

Is that $500 in servicing and u then add the Fuel savings on top of that ??? or is that all inclusive ??

Hey Rob,

The $500/year is an all inclusive figure (service schedule +fuel), that incorporates x2 injector changes at $2000/injector change.

If you only did x1 injector change in the 156000km 10 year period, then you save $2000, or $200/year, which would make the savings go up to $700/year for the diesel.

All depends on how often you need/want to change your injectors.

Best

Mark

[Anth120playdo]

Hey,

Yeah it definitely seems like there's not much difference in servicing costs, the petrol is perhaps slightly cheaper by $100/year according to;

http://www.carservice.com.au/car-ser...auto-09_05-09/

It appears at this stage that the biggest factor in bringing the cost gap between petrol and diesel closer is the extra cost of injectors for the diesel.

The extra cost for injectors is a year dependent variable, and if you're in a 2008+ D4D, you don't have to worry about copper seats etc. However, the very high pressures on CRD will still more than likely dictate changing the injectors perhaps twice in 150000km for any year model.

Similarly for the petrol, there are years that can still bring tears to your eyes with additional costs. Early model 04/05 1GR-FE motors suffer from bad head gaskets, typically blowing on cylinder 6. This can put a 2-3000 bucks sized hole in your wallet!

It looks to me after this early analysis that the cost saving is in the favor of the diesel in the order of $500/year.

Closer than you think!

Best

Mark

Injectors commonly ok average up to 150k. Many with 200-300k but lets not go there.

They need to be replaced every 5-6 years or 120k, whichever comes first.
$2k BDG Injectors fitted. Incl piston inspection, valve clearance check & compression test.
Most people do 120k+ in 5 years, unless its parked & low Klm's vehicle.

[rob_macca67]

It looks to me after this early analysis that the cost saving is in the favor of the diesel in the order of $500/year.

Closer than you think!

Best

Mark

Is that $500 in servicing and u then add the Fuel savings on top of that ??? or is that all inclusive ??

[Whitey]

Hey,

Yeah it definitely seems like there's not much difference in servicing costs, the petrol is perhaps slightly cheaper by $100/year according to;

http://www.carservice.com.au/car-ser...auto-09_05-09/

It appears at this stage that the biggest factor in bringing the cost gap between petrol and diesel closer is the extra cost of injectors for the diesel.

The extra cost for injectors is a year dependent variable, and if you're in a 2008+ D4D, you don't have to worry about copper seats etc. However, the very high pressures on CRD will still more than likely dictate changing the injectors perhaps twice in 150000km for any year model.

Similarly for the petrol, there are years that can still bring tears to your eyes with additional costs. Early model 04/05 1GR-FE motors suffer from bad head gaskets, typically blowing on cylinder 6. This can put a 2-3000 bucks sized hole in your wallet!

It looks to me after this early analysis that the cost saving is in the favor of the diesel in the order of $500/year.

Closer than you think!

Best

Mark