Diesel additives..... Fyrex Ci ?

[Ryeman]

Strange that they specifically tell you to not use additives but then suggest an additive, so for my 2012 103TDI anyone know what they recommend?

[Diesel_vert]

Volkswagen do not recommend using a particular fuel additive product, beyond those already added by the fuel companies, if the fuel meets European standards (refer to EN 228 for petrol, EN 590 for diesel).

Volkswagen prohibit the use of fuels or fuel additives with metallic content. Such products would interfere with the operation of the engine and its emissions devices, esp. the diesel particulate filter (DPF), and may eventually cause damage.

Volkswagen prohibit the use of diesel fuel additives ("flow-improvers") which reduce fuel lubricity. Lack of diesel fuel lubricity can cause damage to fuel injection equipment. Adding petrol to diesel has much the same effect.

Apart from that, Volkswagen does not prohibit the use of fuel additives outright, so the owner is free to use whichever aftermarket or off-the-shelf products they wish, but at the same time, that does not mean taking a carte blanche attitude to what one pours down the vehicle's fuel tank.

There is also the true cost/benefit analysis to consider.

As always, my advice on such matters is to do your research thoroughly.

[bluey]

VAG specifies diesel with cetane 51 for DPF fitted diesels. No diesel fuel in our market meets that. Often they will but the Australian Standard only says CN46. It seems highly likely that extra soot caused by low cetane fuels contributes to DPF failures. BP Ultimate once did have a cetane improver and had a specified minimum cetane over 51, typically 55.

Transporter recommended Morey's Diesel Smoke Killer as a cetane improving additive. I have been using that. Still to get data out of the computer after nearly 30,000k using it in the Yeti. Morey's also has an algicide, which I think is also a good idea with diesel.

[Transporter]

Yes, that's minimum CN51 to be precise.

There is only one reason why VW was/is against the fuel additives. It's because there are many additives that don't have to be suitable for the TDI or TSI engines, besides, one can't ever know what kind of additive comes in the shops tomorrow. Basically, it's beyond VAG control. However, the reputable workshop will most likely use good quality additives.

So, stick with the well known established brands and you can always call to confirm if their product is suitable for your engine, if you aren't sure.

From my experience, I don't recall that I would have to attend the car which was using fuel additives on a regular basis and had a fuel related problem.
But, I do recall many that never used the fuel additive and had a problem with the fuel system.

IMO, there is far less (if any) fuel system faults which could be blamed on the additive, than faults that were caused by poor quality fuel, water in diesel and fuel system components prematurely worn out.

Regular use will extend the life of the components and maintain good fuel economy for much longer, so the cost of the additive will repay itself back many times.

[Diesel_vert]

VAG specifies diesel with cetane 51 for DPF fitted diesels. No diesel fuel in our market meets that. Often they will but the Australian Standard only says CN46.

Volkswagen recommends using diesel fuel that conforms to EN 590 or equivalent.

EN 590 specifies a minimum cetane index of 46, and a minimum cetane number of 51.

Australian fuel standards also specifies a minimum cetane index of 46, but does not specify a minimum cetane number.

In practice, the final product that comes out of Australian terminals has a typical cetane index varying from 49 to 52, according to my own collation of various bits of information on the internet. Depending on the crude oil source and the ASTM method (previous D976 or current D4737) used to calculate the cetane index, the actual cetane number would either be close to, or exceed, the cetane index, which bodes well for everyone.

Rather than cetane, the progressive removal of sulfur in diesel fuel is probably the most significant factor that has contributed to the reduction in smoke emissions and soot (i.e. particulate matter), which of course, what facilitates the introduction of DPFs onto the wider market in the first place. Current sulfur levels in diesel fuel since 2009 is at less than 10 ppm (in line with Europe), down from 50 ppm since 2006, and 500 ppm since 2003.

It seems highly likely that extra soot caused by low cetane fuels contributes to DPF failures.

I think that is an overestimation.

The difference between the cetane number of European and Australian diesel is not so significant as to generate high DPF "failure" rates in this country.

In any case, it is not soot that permanently disables the DPF - it is ash.

Soot can be burnt off during the regeneration process. Metallic compounds, of which the primary source is engine lubricant, reduces to ash during the regeneration process, which cannot be burnt off and will eventually clog up the DPF (hence the need to use low-SAPS or mid-SAPS engine oils, as opposed to full-SAPS).

In addition, UK and European motorists are quite familiar with DPF issues similiar to those experienced by Australian motorists, so it is not a phenomenon unique to this country, irrespective of marque.

Further, it is not inconceivable that faulty parts and componentry have been misdiagnosed for DPF issues. For instance, the G450 sensor in VAG cars have been known to fail, preventing the DPF from operating as intended.

Still to get data out of the computer after nearly 30,000k using it in the Yeti. Morey's also has an algicide, which I think is also a good idea with diesel.

As long as the additive is suitable for the intended application and the value equation stacks up, I don't see much reason why one should not continue using it.

[bluey]

Caltex told me "typical" diesel cetane index here is ">50".

I suspect the question will be answered in a court one day, when a car-loving lawyer has a DPF failure that they don't want to pay to fix. The technical and legal question is - if a manufacturer supplies a product that requires fuel of a certain specification and the fuel widely available clearly does not meet the specification and may well contribute to damage, who should wear the cost?

The simple business deal is that our diesel needs a cetane improver to meet the specification. Car manufacturers could make sure at least one diesel product has a cetane improver and then that would become the recommended fuel.

[Skooter]

Fortuitous that this is top of the forum discussion list, as I was in the local autoparts joint yesterday on an unrelated errand and saw diesel fuel additives and read the labels - almost went for the wallet but decided to check here before adding something to the 103 TDI Skoda Scout, which has not missed a beat since I bought it with 47k on the clock, now 73k.

And of course, all manufacturers recommend you run this stuff in every tank. I use Caltex Vortex from the Woolies joint or BP. Have managed to avoid unknowns for the most part, but eventually a trip into the distant reaches will necessitate filling with whatever is available.

What pricked my interest the most was Penrite DPF Cleaner that is added to the tank - claims to lower soot levels, enhance regen and do so at lower temps (odd, as I thought high temp was required to burn off soot?). Also considering something to ward off the evil fungus. As with others on here, my main concern is adding stuff to a modern hi-tech diesel - huge diff in design parameters compared to the days of the Commer knockers and the belching, crawling semis I remember clawing their way up every incline on the highways we drove on holidays as a kid.

Anyone familiar with the Penrite DPF cleaner stuff? As for general treatment, it's hard to know which to go for where fungus-evasion is the primary motive. What should I avoid? I don't need more performance - more than happy with the beast, especially since an Oettinger remap.

[bluey]

Curious product. MSDS says 60% light petroleum distillates. <4% nasty hydrocarbons. 35% "other stuff". no mention of algicide.

Transporter recommended Morey's Diesel smoke killer and has elsewhere reported on his long-term data collection from vehicles running with that. Have been using Morey's DSK for a few years. Seemed to make a visible difference to soot out the tailpipe (seen in other cars' headlights at night) on non-DPF Polo. Seems to make engine a bit quieter as expected with a higher cetane fuel.

[Ryeman]

?...........

.......... compared to the days of the Commer knockers and the belching, crawling semis I remember clawing their way up every incline on the highways we drove on holidays as a kid...........

.

Ah Pretty Sally, I remember those same belching trucks and am showing my age too.

[Diesel_vert]

Caltex told me "typical" diesel cetane index here is ">50".

I suspect the question will be answered in a court one day, when a car-loving lawyer has a DPF failure that they don't want to pay to fix. The technical and legal question is - if a manufacturer supplies a product that requires fuel of a certain specification and the fuel widely available clearly does not meet the specification and may well contribute to damage, who should wear the cost?

The simple business deal is that our diesel needs a cetane improver to meet the specification. Car manufacturers could make sure at least one diesel product has a cetane improver and then that would become the recommended fuel.

The Australian fuel standard for diesel is incomplete when compared to EN 590 (e.g. minimum cetane number not specified), such that one could never determine with much certainty whether diesel fuel here would comply with EN 590 on paper alone.

In practice, however, that does not mean Australian diesel fuel can never comply with the requirements of EN 590. Given the standard of diesel that is coming out of our fuel terminals (based on typical cetane index, lubricity rating and sulfur content values), it does not necessarily follow that the regular use of such fuel would create issues so significant as to cause damage to the FIE, DPF or the engine itself.

A DPF should function as intended so long as nothing prevents the regeneration process from taking place (which can easily occur under certain operating conditions, which owners need to be made aware of) and the amount of ash is such that exhaust flow is not significantly hampered.

That's not to say the cetane number cannot be increased thorugh user intervention (by adding a fuel additive containing cetane improvers), but the correlation between the cetane index of automotive diesel fuel in Australia and genuine DPF faults, is not strong, IMO.