Sulfated ash...what is it, and how much is too much?

[gregk24]

I was comparing oils the other day and noticed VW 504.00 specs sulfated ash of 1.5% or less, while the thinner 508.00 specs less than 1%.

First of all, what is sulfated ash and is more or less a good thing?

Second, what is the purpose or drive of a manufacturer to spec lower sulfated ash?

 

[jurko]

It stand for Sulfated Ash, Phosphorus, and Sulfur.
It helps oil to retain TBN, resist viscosity shear loss, thermal breakdown, protect against oxidation, wear, corrosion, and deposit formation.

If the SA is too high it can eventually block the DPF (diesel particulate filter)
If the Phosphorus and Sulfur content is too high it can possibly damage catalytic converter.

Low and Mid SAPS oil are primarily made for diesel engines but can be used in gasoline engines without problem.

Use This Tool to find out what is the limit on SA for your application.

​

 

[RooflessVW]

508/509 likely has lower SAPS for GPF compatibility.

More or less isn't necessary better or worse, just different.

 

[Quattro Pete]

I'm simplifying a bit, but the higher the oil's add pack/TBN, the higher the oil's SAPS content. High TBN is good for long OCI, but high SAPS can be bad for emissions equipment, especially on a modern diesel engine.

 

[The Critic]

Most over the counter API SN+/SP oils are probably considered mid-saps.

 

[gregk24]

I'm simplifying a bit, but the higher the oil's add pack/TBN, the higher the oil's SAPS content. High TBN is good for long OCI, but high SAPS can be bad for emissions equipment, especially on a modern diesel engine.

Ok, so what percentage would be considered mid and high saps?

 

[SR5]

Using the Euro ACEA limits you have
Low SAPS Mid SAPS High SAPS >= 1.0 and
Most American style API SN+ / SP and Dexos1-Gen2 oils seem to be about 0.8 to 0.9 %, while most Euro A3/B4 oils seem to be about 1.1 to 1.3 %. (Where SA stands for sulphated ash, the standard way of measuring SAPS level).

 

[Sonofsonof]

A number of Europe's so-called 'high ash' oils started out as being formulated as 'medium ash' oils but were deliberately forced into the high ash camp by ACEA in 2010.

Prior to 2010, you might typically throw together an SL/CF/A3/B3/MB228.1/VW505 oil with 1000 ppm of Phos (so about 1% ZDDP) & 8 TBN (eg 2% 400 TBN Mg Sulphonate). The sulphated ash level might be just shy of 0.8%. There were no formal specific limits on Phos or TBN but there was always massive commercial pressure to minimise DI treat rates & this typically was how things fell out. Yes, the specs said in theory you could go up to 1.6% sulphated ash but nobody in their right mind ever went that far because the law of diminishing returns comes into play.

In 2010, ACEA in its infinite wisdom (sarcasm alert!!) decided that some clear blue water needed to be put between normal oils & the newly emerging low SAPS oils. This they did by slapping a 10 min TBN spec on the older oils. This was easy to implement. You just threw in an extra 2 TBNs worth of over based detergent (in practice a bit more because commercial blenders need a safety margin above the minimum). It was an act of pure spite, a deliberate & unnecessarily costly poisoning of the well to 'encourage' the shift to Low SAPS oils.

Such is life I suppose..

 

[Jetronic]

I got some of the last a3/B4 oils with 8.8 tbn and around 0.88% saps. it was on the MB229.5 list and the reformulated version with 10.4 tbn is aswell.

Bought a lifetime supply, it wasn't expensive either.

 

[Sonofsonof]

I got some of the last a3/B4 oils with 8.8 tbn and around 0.88% saps. it was on the MB229.5 list and the reformulated version with 10.4 tbn is aswell.

Bought a lifetime supply, it wasn't expensive either.

Smart move! Whose oil may I ask? I think got my regular junk up to MB229.3. Don't think ever I managed to get it to MB229.5 (not that anyone cared because folks were happy to settle for 229.1 back then).

 

[Jetronic]

Total quartz 9000 energy 0w-30. believe I paid around 3 euro per litre so on par with the cheapest of the cheap.

 

[SR5]

Couldn’t you keep it as A3/B3 because that still had a min TBN of 8, didn’t only A3/B4 go up to a min TBN of 10?

The fuel economy A5/B5 is still at 8 too for TBN.

 

[Jetronic]

the oil is not elligible for manufacturer approvals as A3/B3.

 

[SR5]

the oil is not elligible for manufacturer approvals as A3/B3.

Got you

 

[Sonofsonof]

Total quartz 9000 energy 0w-30. believe I paid around 3 euro per litre so on par with the cheapest of the cheap.

Back in the day, I did a 0W30 GM/Saab Factory-Fill program for Total. Spent an absolute fortune on engine testing! The final oil was pretty good too.

However when GM sussed just how expensive the oil was, they decided a cheaper 5W30 might better fit their needs, leaving me, jilted at the altar. The truly sad thing was, in their infinite wisdom (yet another sarcasm alert!) GM set up their original FF spec with a 1,200 ppm minimum Phosphorus level. Even at the time, I questioned whether this was a typo and someone had put > when they actually meant
I learnt a painful but valuable lesson from that program. After that I made sure whatever I did could be, if needed, pushed out as a 'market general' product.

 

[Jetronic]

funny enough, this oil had gm approval too gm ll something with 25

so they essentially wanted a break in oil with lots of Phosphorous to keep parts together till broken-in?

 

[OilUzer]

Several of Amsoil SS oils are API SN+ D1G2 ACEA A5/B5 and A1/B1 (obsolete?) with 12.5 TBN.

 

[TiGeo]

I always understood the SAPS thing as the higher the SAPS the higher the TBN to deal with higher-sulfur fuels over the typical drain intervals here in the U.S. vs. Europe that has v. low sulfur fuels and could get away with lower SAPS oils for long-service intervals. In my world, this is the difference between VW502 00 oils (high SAPS) vs. VW504 00 oils (mid or low[?] SAPS).

 

[Quattro Pete]

I always understood the SAPS thing as the higher the SAPS the higher the TBN to deal with higher-sulfur fuels over the typical drain intervals here in the U.S. vs. Europe that has v. low sulfur fuels and could get away with lower SAPS oils for long-service intervals. In my world, this is the difference between VW502 00 oils (high SAPS) vs. VW504 00 oils (mid or low[?] SAPS).

The US now has ultra low sulfur fuel as well, for the most part.

 

[TiGeo]

The US now has ultra low sulfur fuel as well, for the most part.

Correct and that's why say VW can push the 504 oils at the same 10K interval as the 502 oils....still would want to make sure the TBN lasted that whole time!