The costs of having a Petrol vs Diesel

[Alex Roux]

Recently I have been chatting to a friend who drives a petrol model Cruiser bakkie that's been rigged for touring.
He was complaining about his consumption, (around 5 and sometimes less than 5 km/l in traffic).
And it made me wonder again why the TB48 gets such a bad rap.
The EFI 4500 is notoriously heavy on fuel.

Be that as it may, more specifically, given where the price of diesel is nowadays, is it really worth it to have a TD42 rather than a TB48?
I know each has his favourite cup of tea. I like both. But using consumption as the reason for a TD42 is not a forgone conclusion anymore.
The TD42 also needs a bit more attention with more regular oil and oil filter changes. Beyond that, it gets more complicated, as the injection pump and tip service can be pricy, but then later on bigger things may need to get fixed on the petrol too. All in all, I think the TD42 is more costly in terms of maintenance though.

So below is a simplified comparison on three different scenarios - since not all TD42 and TB48s behave quite the same in terms of consumption.
If you disagree with the numbers, or would like a different distance travelled to be used, let me know, and I will gladly update the comparison.

[Peter Connan]

Even when I did my engine swop (March 2019) the running costs were surprisingly similar when doing the calculations on normal pump fuel.

But I had two factors that changed the sums. Firstly at the time bio-diesel was reasonably available at about 60-70% the cost of pump fuel, and secondly my average fuel consumption at the time was 3.8km/l. These two factors made a big difference to the calculations. That first situation has changed now, and the second was unique to me.

However the diesel still has one big advantage: fuel range. It's other advantage is the massive torque available right at cruising speed. It makes for a far more relaxed drive, especially when towing (if you can keep the temperature under control).

The other often-mentioned advantage is the diesel's supposed better bottom-end torque. I still believe this to be false. The perception is due to the fact that the diesel's injector pump has a mechanism built in that attempts to keep the idle speed steady irrespective of load, and the TB series of engines don't. And so the diesel can be left to crawl over obstacles without throttle input. But I remain convinced that in the region below about 1200rpm, the petrol engines have more torque than any TD42 I have driven. It just requires a sensitive toe to access it without surging and breaking traction.

[Alex Roux]

Engine performance is for me a slightly different topic.
As far as low rev torque is concerned, in my view nothing beats a petrol carburetor. But it needs a right foot feathering it, which a big diesel doesn't.
So, even if a TD42 has less torque, not having to feather with your foot changes how you experience rock crawling.

[Tinus lotz]

Very interesting facts ...coming from the calculator ...we know it's true . I agree each one has his own sharm ...thats why my one manual is getting a TB48 just for that....

[TijmenvdS]

I have also been reconsidering the petrol vs diesel recently... ever since I paid R28 a liter for diesel last week
But we dont drive Patrols because it makes any long term sense financially compared to a polo
I think the purchase price makes the biggest difference, once again especially compared to a cruiser but at the end of the day the only thing better than 1 Patrol is another Patrol and Alex has nailed that with 2 diesels and 2 petrols

[Spike]

I can understand the diesel vs petrol A vs B cost comparison for the average guy in a mix of city and leisure driving, but horses for courses. Type of use and availability of fuel are a big factor, for both cost and functionality.

You need a petrol trok in your fleet if you want to drive dunes (Cape, Kalahari, Namibia = petrol territory) The only reason I have a TB48 is because it's my Cape car, and I procrastinated for years before getting it because the cumbersome weight and size doesn't really suit the intended purpose, in comparison to bush driving where the size and weight improve the drive.

In the bush, and up north in africa (excluding Namibia) where you do between crawling speed and about 40kmh on dirt tracks, and up to 60-80kph on "the open road", with diesel fuel readily available due to the proximity of trucks, and would involve detours and route planning to fill with petrol, then in that environment naturally aspirated diesel is king and they chug along like a train.

Turbo-diesel are attractive because they are a happy medium ticking most boxes adequately to cover all bases. But turbo diesel patrols are just pretty scarce unfortunately

[ra_01]

I can understand the diesel vs petrol A vs B cost comparison for the average guy in a mix of city and leisure driving, but horses for courses. Type of use and availability of fuel are a big factor, for both cost and functionality.

You need a petrol trok in your fleet if you want to drive dunes (Cape, Kalahari, Namibia = petrol territory) The only reason I have a TB48 is because it's my Cape car, and I procrastinated for years before getting it because the cumbersome weight and size doesn't really suit the intended purpose, in comparison to bush driving where the size and weight improve the drive.

In the bush, and up north in africa (excluding Namibia) where you do between crawling speed and about 40kmh on dirt tracks, and up to 60-80kph on "the open road", with diesel fuel readily available due to the proximity of trucks, and would involve detours and route planning to fill with petrol, then in that environment naturally aspirated diesel is king and they chug along like a train.

Turbo-diesel are attractive because they are a happy medium ticking most boxes adequately to cover all bases. But turbo diesel patrols are just pretty scarce unfortunately

Thanks for this Alex, this is an interesting post and stats. Consumption on an 4.8 can be improved with a proper diff ratio. Recently I upgraded to 33inch tyres and done a 4.1 ratio conversion. I have to say, the consumption on a high way is 6.5 with roof top tent and loads of stuff in boot and 4 adults. Still early stages, as I have done only one trip (to Kruger). But will update after my Namibia trip in Dec, which will give me a proper indication.

Spike, do you think diesel is better up north due to availability of diesel or consumption?

[Spike]

Spike, do you think diesel is better up north due to availability of diesel or consumption?

For me yes. Where ever truck traffic goes you're guaranteed to get diesel.
It might well be different for somebody who sticks mostly to busy routes that have regular tourist and local traffic. I can go for weeks, months even, without seeing an overlander passing. In Northern Moz for example I know a guy who drives his Safari petrol bakkie with a 200 litre drum on the back to help save hassle when he needs petrol. If his nearest town is out of petrol, which happens regularly, then it's a long drive to the next big town

[ra_01]

Thank you Spike.

For the purpose of this thread; Can 3.0 CRD and Di owners post their stats as well, for a comprehensive view?

[Peter Connan]

Spike, do you think diesel is better up north due to availability of diesel or consumption?

For me yes. Where ever truck traffic goes you're guaranteed to get diesel.
It might well be different for somebody who sticks mostly to busy routes that have regular tourist and local traffic. I can go for weeks, months even, without seeing an overlander passing. In Northern Moz for example I know a guy who drives his Safari petrol bakkie with a 200 litre drum on the back to help save hassle when he needs petrol. If his nearest town is out of petrol, which happens regularly, then it's a long drive to the next big town

A Canadian chap drove around Africa a couple of years ago in a Petrol Jeep. While he did add some extra fuel capacity to the vehicle, his conclusion was that he was always able to find fuel because the most common mode of transport is scooters and small motorbikes which are all petrol-powered. However on several occasions he had to resort to buying fuel in small containers as that's all that was available.

I would love to hear your opinion on this, as I have never travelled further north than the Zambezi.