Quote:
Originally Posted by Assimilator1
Ugh, acronym rich! But appreciate the reply still 
Do GTL oils have a slightly narrower VI than PAO/POE oils? In my admittedly short search I couldn't find out how well it compared to them, other than "well" 
Mobil1 reformulated all oils starting in 2015 bcs
What's bcs?
Carbon Build Up (CBU). Sulfated ash and phosphorous (SAPS) are main drivers behind CBU.
Ok I find that statement confusing, Sulphur and Phosphor lead to Carbon build up?? I thought Carbon build up was largely poorly burnt HCs (oil and fuel), or does that include compounds of Carbon+Sulphur and/or Phosphor?
Re Noack, which oil property/spec is that listed as?
Re burning oil, roger that, I just don't know how much mine burns as I haven't driven it enough (even less than I 1st thought at about 600 miles! That'll change this year  ).
What are the consequences of burning off a lot of zinc? O2 sensor problems?
So, going back to Mobil 1 vs Castrol comparison, am I right in saying that although the Mobil 1 has slightly higher SAPs, which could slightly increase CBU on the intake valves in theory, the fact that the S65 has port injection means it shouldn't make any material difference?
For those like me who don't automatically know/remember what all these acronyms mean.
PAO oil - Polyalphaolefin synthetic oil has a much wider Viscosity Index vs mineral oil, amongst other advantages (read link for more in).
POE oil - Polyolester, another synthetic oil, with a wider VI than mineral oils (see graph in above link).
GTL - Gas To Liquids (synthetic oil made from gas, also better than mineral oils, but I couldn't find how precisely it compared to PAO and POE oils).
UOA - Used Oil Analysis (sending off an oil sample to a lab)
TBN - Total Base Number (alkaline additives to counter acid build up) |
Bcs. Because. Shell is early adopter of Gas to Liquid base (GTL). Mobil1 followed that, but IMO, SHell has better technology. That does not mean Mobil1 oils are less of oil. Mobil1 mixes PAO (Group IV) and Esters (POE or Group V) in oil to achieve what they want.
But it is not as simple as that. It depends what they mixed in lab,whether base stock is heavy or light whether it will have higher VI. Higher VI is not necessarily good. It is good indication how it will affect fuel efficiency. But, this is where I appreciate Mobil1 or Motul. Shell/Pennzoil is very proud that their 0W30 oil has VI of 204. But, they do not post what is HTHS. In engines like S65 everything is about HTHS, VI is irrelevant. Very high VI usually means mediocre HTHS.
EVaporation loss or Noack is something that companies do not post just like that. Noack in port injected cars does not mean a lot. But it indicates what base stock is used in oil. For example, Noack of Mobil1 0W40 is 8.7%. That is excellent achievement for oil like that. How they achieved that? GTL, PAO and POE combination. Noack of Liqui Moly 5W40 (lower Noack is easier to achieve in 5W40 than 0W40 is same base stock is used bcs. less VII) is 11%. That tells you that LM is using Group III base stocks and more VII. Many companies decide to not post these numbers. How I know? There is very good russian web site where a lot of these oils are tested in lab, so very often they test Noack:
https://translate.google.com/transla...B%2F&sandbox=1
Now, this web site does not have 10W60 oils, but reviewing other oils, you can get idea which oil companies are at forefront of research and performance.
Now SAPS. It is oil and fuel, but how much oil? That depends on Noack. Lower Noack, less oil. But deposits itself are constituted from SAPS, as SAPS is extremely hard to burn (reason why oils design for DPF/GPF equipped vehicles are so called Low-SAPS oils, ACEA C3, C2, C5).
In S65 that does not matter. Port injection will solve deposit issue. Only way to 100% mitigate CBU issue in DI engines is duel DI and Port injection. For example VW uses that in European version of their EA888 engines. Toyota uses that in 2GR-FKS engines.
But in S65, or my N52, no worries. Port injection, naturally aspirated engine, no CBU.
So, Mobil1 10W60, bcs. it is so additive rich might be good for S65. Everything in that oil is there to prevent wear at worse conditions.
ZDDP? Oil burn with high ZDDP will create concrete wall in your CAT. Not O2 sensor, but actually ruin your CATs