How do you define a semi synthetic oil?

[skyship]

I was just reading another post where some chap mentioned that a semi synthetic engine oil was recommended and this is one subject that I find interesting, as how do you define a semi synthetic oil, apart from the fact it is a dino oil with extra synthetic additives.

If anyone asks me what type of oil they should use, then apart from suggesting they look in their manufacturers handbook or ask the dealer, it often becomes a case of listing a full synthetic oil or a basic dino oil.
To further confuse matters the Brits and the Americans don't use the same oil groups as the Germans, so you have to then figure out if you want to include HC (Hydrocrack) oils in the fully synthetic category or do what the Germans do and refer to them as synthetic technology oils. As I live in Germany I only consider an oil as fully synthetic if it meets the more exacting German standards and it is often worth check the German oil sites to find out if an oil you are buying is a genuine synthoil or not.

Unfortuntately there are some new cheap HC synthetic engine oil brands starting to appear in the UK and US under the fully synthetic label that have verious dubious base stocks and add packs, so it is definitely worth check on which group a new oil is in, although often it is just a case of you get what you pay for with new engine oils.
At the end of the day I think the Germans are very correct in the way they define oil groups and the terms part synthetic and HC synthetic were dreamt up by oil company sales teams trying to change the image of their cheap dino oils for a more high tech man made one.

 

[volk06]

Originally Posted By: skyship
I was just reading another post where some chap mentioned that a semi synthetic engine oil was recommended and this is one subject that I find interesting, as how do you define a semi synthetic oil, apart from the fact it is a dino oil with extra synthetic additives.

If anyone asks me what type of oil they should use, then apart from suggesting they look in their manufacturers handbook or ask the dealer, it often becomes a case of listing a full synthetic oil or a basic dino oil.
To further confuse matters the Brits and the Americans don't use the same oil groups as the Germans, so you have to then figure out if you want to include HC (Hydrocrack) oils in the fully synthetic category or do what the Germans do and refer to them as synthetic technology oils. As I live in Germany I only consider an oil as fully synthetic if it meets the more exacting German standards and it is often worth check the German oil sites to find out if an oil you are buying is a genuine synthoil or not.

Unfortuntately there are some new cheap HC synthetic engine oil brands starting to appear in the UK and US under the fully synthetic label that have verious dubious base stocks and add packs, so it is definitely worth check on which group a new oil is in, although often it is just a case of you get what you pay for with new engine oils.
At the end of the day I think the Germans are very correct in the way they define oil groups and the terms part synthetic and HC synthetic were dreamt up by oil company sales teams trying to change the image of their cheap dino oils for a more high tech man made one.


There is more to a semi synthetic than just extra additives.
A semi-synthetic has Group III, IV, V blended with Group II or II+, meaning it has a percentage of synthetic base stocks mixed with conventional basestocks. Your correct about Germany only being able to label acutal "synethic" oil and can't claim Group III to be synthetic. Here in the US if it performs just as good or better from a blend of Group III, IV, V it can be considered full synthetic. Thanks to Castrol and XOM. Most full synthetics in the US are group III based except for boutique oils.

Heres a good discussion.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=950368&page=1

 

[Garak]

Originally Posted By: volk06
There is more to a semi synthetic than just extra additives. A semi-synthetic has Group III, IV, V blended with Group II or II+, meaning it has a percentage of synthetic base stocks mixed with conventional basestocks.


Wouldn't that be a synthetic blend, rather than a semi-synthetic? At least from the German standpoint, I thought that a Group III was considered semi-synthetic or synthetic technology. Here, something like our usual HM oils are synthetic blends. Of course, I'm mixing German and North American definitions, so that's not terribly helpful.

 

[chubbs1]

I will just add that just because you have a conventional oil ie. grp. III or even II-II+ doesn't mean it is bad, nor does having a true syn always good. It is the application, cost and a host of factors that you should make before writing off HC oils.

 

[ARCOgraphite]

ELF found in extensive studies that a blend worked better than majority high group synthteic in racing and High performance street apps. That was over ten years ago, though. There mor to a lube than cold flow or high coking temps - there is general lubricity and specifice mechanism lubrication needs. Some high group oils with poor traction or wetting will damage some engines with specific mechanisms.

 

[A_Harman]

My definition of semi-synthetic oil is a blend of groups I, II, and III with Group IV and V. I don't consider Grp III oils to be synthetic unless they are isomerized to give a tight distribution of molecular weights. Severely cracked and hydrotreated base stock is broken down from larger molecules, and is only analytic, not synthetic. GTL I consider to be synthetic because new molecules are synthesized by combining smaller molecules.

 

[volk06]

Originally Posted By: Garak
Originally Posted By: volk06
There is more to a semi synthetic than just extra additives. A semi-synthetic has Group III, IV, V blended with Group II or II+, meaning it has a percentage of synthetic base stocks mixed with conventional basestocks.


Wouldn't that be a synthetic blend, rather than a semi-synthetic? At least from the German standpoint, I thought that a Group III was considered semi-synthetic or synthetic technology. Here, something like our usual HM oils are synthetic blends. Of course, I'm mixing German and North American definitions, so that's not terribly helpful.

Semi-synthetic = synthetic blend. Semi has the definition meaning partially, so in this case partially synthetic.

I don't know about the German language definitions.

 

[Boatowner]

One thing to do is look at the MSDS or product info sheet for the flash point. It doesn't tell everything about how good the oil is, far from it, but it does indicate something about it properties. It should be over 400 degrees F to be considered any kind of synthetic. Pour point give valuable information also.

 

[Garak]

Originally Posted By: volk06
Semi-synthetic = synthetic blend. Semi has the definition meaning partially, so in this case partially synthetic.

I don't know about the German language definitions.


There we go - a giant ball of confusion.

If I recall correctly, I've seen product lines that included semi-synthetic and synthetic blends as distinct products, but that was some time ago. Since Group IIIs have been marketed as synthetics and since synthetic blends have all but disappeared up here (except for HM oils), I have not observed that.