Diesel, standard vs low sulphur

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thepot
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Diesel, standard vs low sulphur

Post by thepot »

Hi All,

I'm not sure if this has been discussed, but is there a major difference between standard diesel and low Sulphur diesel?

My wife has a Duster 1.5DCi and the difference at the pump between standard and low sulphur is almost R1/ltr.

Will the standard be worse for engine/injectors longevity?
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mk2-phreak
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Re: Diesel, standard vs low sulphur

Post by mk2-phreak »

Most fuel stations have 50ppm (low sulphur). Use that for a modern turbodiesel engine. Sasol has 10ppm, even lower, but often more expensive. Use that if you can afford it
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Re: Diesel, standard vs low sulphur

Post by Neuk »

I suggest using whatever is recommended for the car in question.
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Re: Diesel, standard vs low sulphur

Post by DJ7 »

Neuk wrote: Wed Mar 02, 2022 12:28 pm I suggest using whatever is recommended for the car in question.
With later model cars it is always the lower sulfur variant that is recommended. :thumbup:
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thepot
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Re: Diesel, standard vs low sulphur

Post by thepot »

Update:

What I have realised by keeping a log book, is that the quality of diesel varies quite a bit between brands.

Currently Sasol gives me about an extra 30kms per R200 filling up over Caltex.

Next up for testing is our local Agri supplier BKB, as they are much cheaper compared to standard filling stations.
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Re: Diesel, standard vs low sulphur

Post by Jetta2 »

thepot wrote: Wed Apr 13, 2022 3:17 pmCurrently Sasol gives me about an extra 30kms per R200 filling up over Caltex.
Exactly the same roads and routes, exactly the same driving conditions (weather, traffic volumes,etc), exactly the same speeds, exactly the same throttle openings, etc?
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Re: Diesel, standard vs low sulphur

Post by mk2-phreak »

Jetta2 wrote:
thepot wrote: Wed Apr 13, 2022 3:17 pmCurrently Sasol gives me about an extra 30kms per R200 filling up over Caltex.
Exactly the same roads and routes, exactly the same driving conditions (weather, traffic volumes,etc), exactly the same speeds, exactly the same throttle openings, etc?
I've done back to back tanks with both my B7 and a Q7 3.0 TDI, there was no significant differences in mileage achieved between Engen, Caltex, Shell or Sasol 50ppm Diesel.

With the exception of Sasol, all the diesel is coming from the same refinery.

I will say that with Sasol ultra low sulphur diesel (10ppm) the engines did seem to run smoother.
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Re: Diesel, standard vs low sulphur

Post by missioner »

thepot wrote:Hi All,

I'm not sure if this has been discussed, but is there a major difference between standard diesel and low Sulphur diesel?

My wife has a Duster 1.5DCi and the difference at the pump between standard and low sulphur is almost R1/ltr.

Will the standard be worse for engine/injectors longevity?
Do NOT use 500ppm diesel, AKA Standard diesel, in any modern common rail fed engine, especially not in a Duster DCi. The Continental/VDO injectors in this car are not serviceable and if they fail, which happens often even with 50ppm, it's costly to replace them.

To qualify what I mean by modern, is pretty much everything after 2005 including HMV and Agri machines.

The evidence of what this fuel does to an engine is not apparent in a short time but rather is accumulative. The higher sulphur content makes the fuel abrasive and gradually erodes the high precision parts of the fuel system down till they fail.

The same is true for the engine internals such as pistons and piston rings. To mitigate this one would have to run much shorter service intervals, like in the old days.

Don't do it, we have the technology.
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thepot
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Re: Diesel, standard vs low sulphur

Post by thepot »

I really appreciate all the input.

Will stick with Sasol then. BKB do supply some non-mainstream service stations with 50ppm. But after reading above I'm not sure I can trust them lol.

@Jetta2, Yes driving conditions and routes are pretty much the same week to week.

Thanks once again.
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Re: Diesel, standard vs low sulphur

Post by Neuk »

mk2-phreak wrote: Wed Apr 13, 2022 6:58 pm
Jetta2 wrote:
thepot wrote: Wed Apr 13, 2022 3:17 pmCurrently Sasol gives me about an extra 30kms per R200 filling up over Caltex.
Exactly the same roads and routes, exactly the same driving conditions (weather, traffic volumes,etc), exactly the same speeds, exactly the same throttle openings, etc?
I've done back to back tanks with both my B7 and a Q7 3.0 TDI, there was no significant differences in mileage achieved between Engen, Caltex, Shell or Sasol 50ppm Diesel.

With the exception of Sasol, all the diesel is coming from the same refinery.

I will say that with Sasol ultra low sulphur diesel (10ppm) the engines did seem to run smoother.
Depending where you live, with the exception of 10ppm, it is likely that even Sasol 50ppm or 500ppm comes from the same refinery as other brands.
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Re: Diesel, standard vs low sulphur

Post by Neuk »

thepot wrote: Thu Apr 14, 2022 10:09 am I really appreciate all the input.

Will stick with Sasol then. BKB do supply some non-mainstream service stations with 50ppm. But after reading above I'm not sure I can trust them lol.

@Jetta2, Yes driving conditions and routes are pretty much the same week to week.

Thanks once again.
All base fuel made locally is made to the exact same standards and fully imported base fuel has to conform to the same or similar standards with the only differences between brands being the additives that are added either in the tanker before delivery to a fuel station, in tanks at fuel stations or while being pumped in to a vehicle. Sasol is able to make 10ppm due to it having one refinery that refines fuel from coal and with the exception of this refinery and the PetroSa refinery which uses gas all refineries in SA use imported crude oil to refine fuel.
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Re: Diesel, standard vs low sulphur

Post by VAG Fan »

One should differentiate between the engine parts lubricated by the Diesel itself (Diesel pump, injectors, tandem pump, unit injectors, high pressure pump, etc. - depending on the exact engine), and those that are lubricated by oil (pistons, engine bearings, cams, rollers / followers etc.).

In terms of Diesel lubricity, I am skeptical about the notion that higher sulphur content makes Diesel "abrasive". To the contrary, sulphur compounds would actually add lubricity to the fuel. (Extreme pressure additives in gearbox oil, for example, are sulphur based.) But even low sulphur fuel is "supposed" to contain sufficient lubricity additives, as lubricity is part of the standards that Neuk mentioned.

What the sulphur does do, is create more acidity in the engine oil, because blow-by gases contain SO2, SO3 and water vapour, which combine to form sulphurous and sulphuric acid, which must be neutralised by the additive package in the oil. So, the higher the sulphur content, the faster the detergents in the oil are used up, which is counterproductive with long service intervals.

Sulphur can also poison an exhaust catalyst.
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Re: Diesel, standard vs low sulphur

Post by missioner »

VAG Fan wrote:One should differentiate between the engine parts lubricated by the Diesel itself (Diesel pump, injectors, tandem pump, unit injectors, high pressure pump, etc. - depending on the exact engine), and those that are lubricated by oil (pistons, engine bearings, cams, rollers / followers etc.).

In terms of Diesel lubricity, I am skeptical about the notion that higher sulphur content makes Diesel "abrasive". To the contrary, sulphur compounds would actually add lubricity to the fuel. (Extreme pressure additives in gearbox oil, for example, are sulphur based.) But even low sulphur fuel is "supposed" to contain sufficient lubricity additives, as lubricity is part of the standards that Neuk mentioned.

What the sulphur does do, is create more acidity in the engine oil, because blow-by gases contain SO2, SO3 and water vapour, which combine to form sulphurous and sulphuric acid, which must be neutralised by the additive package in the oil. So, the higher the sulphur content, the faster the detergents in the oil are used up, which is counterproductive with long service intervals.

Sulphur can also poison an exhaust catalyst.
Thanks for the added details about this.

Always good to learn more.
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