Originally Posted By: gfh77665
"Are dinos perfectly equivalent to synthetics?" As it pertains to Longer OCI? and Cleaner engines?
There are two ways an oil can contribute to a "cleaner engine": the oil may prevent deposits, or the oil may actively dissolve and disperse existing deposits. In both cases, the additives, including detergents, dispersants, and anti-oxidants, play a much larger role than the base oil.
A synthetic base oil may contribute to
preventing deposits by nature of its better oxidative stability, assuming it also has a solid additive system. A weak additive system can override the effects of the synthetic base oil in this regard, so the fact that the oil is "synthetic" is not a guarantee it will be better at preventing deposits. In fact, under some conditions, such as thin oil films at very high temperatures, non-polar synthetics like PAO and Group III are actually
more prone to forming deposits because of their inability to dissolve deposit precursors. While these conditions are rare in automotive engines, they do preclude the use of PAO and Group III in certain applications such as jet engines, reciprocating air compressors, and oven chain lubricants.
With respect to the base oil's abiliy to
clean existing deposits, polarity is the key factor. Conventional Group I base oils are much more polar than synthetic PAOs and Group IIIs and may clean better provided they are robustly inhibited for oxidation. Most are not, however, since anti-oxidants are expensive, so the lower oxidative stability of Group I base oils often overrides their better dissolving power. Non-polar synthetic base oils like PAO and Group III contribute nothing in and of themselves to cleaning existing deposits. That said, such synthetic oils often contain a more robust additive system since they usually represent an oil company's flagship product or "best foot forward."
The only synthetic base oils that both prevents deposits
and cleans existing deposits are esters (and to a lesser degree alkylated naphthalenes), but these are so expensive that they are rarely used in engine oils in a meaningful dosage.
Regarding extended OCIs, synthetic oils have the
capacity to contribute significantly to longer OCIs through their better oxidative stability, provided once again that they have a robust additive system. A weak or mediocre additive system can neutralize the benefits of the synthetic base oil and the finished oil may offer no OCI extension at all, even though it is "synthetic".
It is important to understand that many if not most marketers of synthetic oils
do employ a more robust additive system since this oil is their top shelf offering and often utilizes their best technology. Since they have to put more money into the base oils and can sell it at synthetic prices, why not invest more in the additive package as well. This is especially true with very expensive base oils such as PAO and Group III+. It's not a sure thing, but the probability is higher that synthetic oils have both better base oils
and better additive systems, and therefore may be both cleaner and extend OCIs.
So, the definitive answer to your question "Are dinos perfectly equivalent to synthetics as it pertains to Longer OCI and Cleaner engines?" is absolutely YES....and NO. Or to be more concise,
it depends!
Tom NJ