Does conventional offer the same protection as synthetic?

[AlphaOmega]

I understand that synthetic is more durable/will last longer, but assuming OCI of 3k, will a conventional A3/B4 provide the same wear protection as a synthetic A3/B4 in plane, regular use? (No -30F starts, no hot-lapping hours on end, etc)

 

[Revving2Redline]

Over how long?
Start up?
Eventually that conventional is going to go out of grade faster than synthetic will.

 

[zrxkawboy]

Generally speaking, I would say yes.

 

[kschachn]

Where are you buying a conventional ACEA A3/B4 oil and at what price?

And "wear protection" isn't determined by base stock composition, whatever wear protection means exactly.

 

[AlphaOmega]

Where are you buying a conventional ACEA A3/B4 oil and at what price?

And "wear protection" isn't determined by base stock composition, whatever wear protection means exactly.

This is a question out of general curiosity. By "wear protection" I mean, I guess, consistency and strength of the oil film and lubricity. I don't know if those are legitimate terms/concepts, but I'll like to learn

 

[kschachn]

Oil film strength and lubricity are pretty much irrelevant, film thickness (MOFT) is definitely relevant. That is directly related to wear protection and is related to the HT/HS of the oil. ACEA A3/B4 oils have a minimum 3.5 HT/HS which will protect most engines from excessive wear under most all conditions.

 

[Duffyjr]

You say 3k but how long as in time, 3 months vs a year may give a different answer.

 

[AlphaOmega]

Oil film strength and lubricity are pretty much irrelevant, film thickness (MOFT) is definitely relevant. That is directly related to wear protection and is related to the HT/HS of the oil. ACEA A3/B4 oils have a minimum 3.5 HT/HS which will protect most engines from excessive wear under most all conditions.

Excellent, thanks! That's what I was (randomly) wondering in my head. Essentially, synthetic oil lasts longer and is more durable, but otherwise - all else being equal - two oils with identical certifications, one synthetic, one conventional will protect an engine the same

 

[kschachn]

Excellent, thanks! That's what I was (randomly) wondering in my head. Essentially, synthetic oil lasts longer and is more durable, but otherwise - all else being equal - two oils with identical certifications, one synthetic, one conventional will protect an engine the same

Which conventional ACEA A3/B4 oil are you using for this comparison?

And your summary isn’t exactly what I said.

 

[AlphaOmega]

You say 3k but how long as in time, 3 months vs a year may give a different answer.

What I meant is if, inherently, synthetic oil protects against wear (under plane, regular conditions) better than a matching conventional oil, BEFORE conventional oil is degraded, say during the first 3k mi/3 months

 

[kschachn]

Wear isn’t everything. Most any oil provides adequate protection against wear.

 

[OVERKILL]

Excellent, thanks! That's what I was (randomly) wondering in my head. Essentially, synthetic oil lasts longer and is more durable, but otherwise - all else being equal - two oils with identical certifications, one synthetic, one conventional will protect an engine the same

A3/B4 is a "foundational" approval, that is, most of the approvals you'd actually be looking for would be built on top of that; it would be used as a building block or to set the minimum level of performance, the limits for which are typically restricted further with the OEM specs as well as expanded/improved upon using their own tests and protocols.

If you have an application where A3/B4 is the only requirement, yes, in theory, any oil with the same approval should perform the same, however, more advanced approvals with tighter limits on a competing product (like say M1 0w-40) are going to mean it will perform better more broadly, but that would be next to impossible for Joe Average car owner to qualify.

As an example: Recently, there was an Engineering Explained video posted that showed some of the API sequences and many folks plug API SP as being a big upgrade from SN/SN Plus. The video was sponsored by Mobil and they showed a few of the tests and spoke about some of the limits. One of the limits was for oxidative thickening where, with API SP, the allowance was reduced from 150% to 100% increase, Mobil limits themselves to 10% for M1, 5% for M1 EP. So, confined within the basic foundational approval regimen, that does not mean that all oils are going to perform the same, it just means they meet the same bar for performance, and in many cases the results of that are going to be "fine". But that does not mean that a superior product isn't going to perform better in ways that will have an impact later on in the engine's life, like cleaner ring lands, lower blowby, less consumption, less varnish...etc.

 

[kschachn]

As an example: Recently, there was an Engineering Explained video posted that showed some of the API sequences and many folks plug API SP as being a big upgrade from SN/SN Plus. The video was sponsored by Mobil and they showed a few of the tests and spoke about some of the limits. One of the limits was for oxidative thickening where, with API SP, the allowance was reduced from 150% to 100% increase, Mobil limits themselves to 10% for M1, 5% for M1 EP. So, confined within the basic foundational approval regimen, that does not mean that all oils are going to perform the same, it just means they meet the same bar for performance, and in many cases the results of that are going to be "fine". But that does not mean that a superior product isn't going to perform better in ways that will have an impact later on in the engine's life, like cleaner ring lands, lower blowby, less consumption, less varnish...etc.

Oxidation resistance and resistance to deposit and sludge formation are key benefits to synthetic oils.

 

[OVERKILL]

Wear isn’t everything. Most any oil provides adequate protection against wear.

Exactly. Wear control is controlled by the additive package, which could be identical basically for a Group III synthetic and a Group II conventional.

 

[OVERKILL]

What I meant is if, inherently, synthetic oil protects against wear (under plane, regular conditions) better than a matching conventional oil, BEFORE conventional oil is degraded, say during the first 3k mi/3 months

"Plain, regular conditions" vary depending on the engine and what it is fitted to. Honda's 1.5L engine for example is a massive fuel dilution nightmare, despite being quite pedestrian and fitted to some rather unremarkable vehicles. High levels of fuel dilution have a negative impact on both wear control and oxidation and thus premature breakdown of the lubricant and base oils, resulting in varnish build-up. Varnish build-up in the ring land area will mean more oil consumption and more blowby, which will exasperate the issue.

It isn't the protection against wear that's the issue, as @kschachn noted, but rather the ability for synthetic oils to handle oxidation and resist breakdown that is the big difference. This becomes more relevant in the presence of increased contaminant loads in engine that are so inclined. The base oil viscosity of a synthetic will also tend to be higher, with less in the way of VII polymers, so viscosity change over the OCI will be better controlled as well, either thickening (oxidation) or thinning due to mechanical shear. Dilution is another factor, but isn't countered by the higher BOV or reduced VII content.

 

[CKN]

A 3,000 mile OCI even with conventional oil is a BITOG "money flush".

 

[PimTac]

Here is a extensive thread on the same subject.


https://bobistheoilguy.com/forums/threads/does-synthetic-protect-better-than-dino.342631/

 

[loneryder]

Where are you buying a conventional ACEA A3/B4 oil and at what price?

And "wear protection" isn't determined by base stock composition, whatever wear protection means exactly.

I thought an A3 oil had to be synthetic to meet the standards?

 

[OVERKILL]

I thought an A3 oil had to be synthetic to meet the standards?

You could do a 10w-40 with just the EHC.

 

[BMWTurboDzl]

I understand that synthetic is more durable/will last longer, but assuming OCI of 3k, will a conventional A3/B4 provide the same wear protection as a synthetic A3/B4 in plane, regular use? (No -30F starts, no hot-lapping hours on end, etc)

Answer: On a 3k OCI the answer is probably. It depends on the engine in question and other attributes of the oil you wish to use (HTHS, addpack).

Is conventional even sold any more?

You don't think you could find what I would consider conventional* oil meeting any ACEA specification because they're all long-drain interval oils.

*No Gr 3, 4, 5 base oils This would be API SH and prior