Please educate this noobie on the differences of base stock numbers. I hear about group II and III and such, but have no clue as to what is what.
Different base stocks
- Thread starter RobWest
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GI- solvent refined petroleum base stock. It is common belief that no SL rated oil uses 100% GI basestock, but some of them do have some GI in them.
GII- hydrotreated petroleum base stock. More refined, with less gunk in it. More stable, and usually with a higher viscosity index. Chevron and pennzoil oils use nothing but this group in their oils. Common belief that all SL oils use this in a certain amount.
GIII- "hydrocracked" or severely hydrofinished base stock. Castrol won the right for oil blenders to call this group "synthetic". Most OTC synthetics are made from this base. I think they use the same process to make it as GII, but take it a step further.
G-IV PAO base stock. Chemically produced from ethelene gas. True synthetic oil, and primary basestock used in mobil, amsoil and most top tier synthetics. Much more stable and has higher VI index than GIII. Can handle more extreme temps.
G-V ester base stock. used in most synthetic oils for miscibility, and is primary base used in redline and a few others. Extreme natural detergency and cleaning ability. Strong attraction to metal. Can withstand more extreme temps than PAO.
I am sure that the experts around here can give you a much better definition of the base stocks.
GII- hydrotreated petroleum base stock. More refined, with less gunk in it. More stable, and usually with a higher viscosity index. Chevron and pennzoil oils use nothing but this group in their oils. Common belief that all SL oils use this in a certain amount.
GIII- "hydrocracked" or severely hydrofinished base stock. Castrol won the right for oil blenders to call this group "synthetic". Most OTC synthetics are made from this base. I think they use the same process to make it as GII, but take it a step further.
G-IV PAO base stock. Chemically produced from ethelene gas. True synthetic oil, and primary basestock used in mobil, amsoil and most top tier synthetics. Much more stable and has higher VI index than GIII. Can handle more extreme temps.
G-V ester base stock. used in most synthetic oils for miscibility, and is primary base used in redline and a few others. Extreme natural detergency and cleaning ability. Strong attraction to metal. Can withstand more extreme temps than PAO.
I am sure that the experts around here can give you a much better definition of the base stocks.
Experts? What you typed was pretty impressive!
Very nice outline!
Q:Can a group II be Both Hydrotreated and Hydrocracked?
If so what is this Called?
Q:Can a group II be Both Hydrotreated and Hydrocracked?
If so what is this Called?
Patman
Staff member
I think as it stands right now, Group 5 is actually a "catch all" category for any type of full synthetic base oil which isn't PAO, so it's not just limited to esters only, but esters and any other special synthetic base oils (can't think of their names offhand)
I could be wrong but I thought I recall a recent article in that online lube report which mentioned a possible group 6 category being made in the future??
Here is the post by Patman on group VI base.
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000219
Regards,
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000219
Regards,
Patman
Staff member
Thanks! I'm glad I wasn't imagining things.
So basically any quality dino oil I buy will be a Group II and synthetics can be anywhere from Group III to Group V? And any cheap synthetic will most likely be a III? I notice a huge difference in price between some synthetics. The Super Tech is like $2.99 a quart, but the brand name stuff is always $4 or above.
Great outline.
What is GII+?
Group II+ is the base stock used by Shell, Pennzoil, Chevron, Conoco/Phillips. Just a little more highly refined than Group II.
and could include some group II
Rob, the base stock is definitely important, but I would not get too hung up on that. The additive package is extremely important.
An oil labeled synthetic may not be all that great if the additive package is weak.
That is why looking at voa and uoa's is important.
An oil labeled synthetic may not be all that great if the additive package is weak.
That is why looking at voa and uoa's is important.
Rob, I think you'd better put on some insect repellant, you are about to get bitten by the oil bug!
This is a great site and you can learn some neat stuff by reading old posts and going into the various info categories. If you want to use a conventional oil with a great base stock, 3 of the better ones are Pennzoil, Motorcraft and Chevron Supreme (or Havoline if it says 'Chevron' on the back label). There are others, you just have to do some research.
Just looked at base oils on the ChevronTexaco website. I had assumed that the Group II+ designation was just an informal term kicked around the BITOG forum.
Chevron actually labels an oil with a 118 VI number as II+. What is the VI number range that designates II+ ?
Chevron actually labels an oil with a 118 VI number as II+. What is the VI number range that designates II+ ?
Patman wins the prize. 10,000 posts!
Group II+ base stocks have a viscosity index range of 110-119. Group III starts at 120. If Chevron's Group II+ is 118, it's not far at all from a Group III. Group II+ is an industry convenience. It's not an official API category. (yet, anyway) There've been rumors that "Chevron Supreme" (and by extension, probably ChevronTexaco-made "Havoline") use some proportion of Group II and Group II+ base stocks. The same is held likely for Pennzoil. If true, these brands, at least (maybe more?), would constitute state-of-the-art blends for conventional motor oils.
Patman
Staff member
I hope the prize is a new Corvette! (or even a used one would be nice, as long as it's a 97 or newer)
Too late bro, I already have the bug! And I've already been converted to a Chevron/Havoline guy after only 4 days! I wasn't really getting hung up on base stocks, just curious as to what they actually meant and which types of oils were made from each type.quote:
Originally posted by mikemc:
Rob, I think you'd better put on some insect repellant, you are about to get bitten by the oil bug!This is a great site and you can learn some neat stuff by reading old posts and going into the various info categories. If you want to use a conventional oil with a great base stock, 3 of the better ones are Pennzoil, Motorcraft and Chevron Supreme (or Havoline if it says 'Chevron' on the back label). There are others, you just have to do some research.
But these are not set in stone.
A group II could have a higher VI right!
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