Different base stocks

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52
Location
Poquoson, VA.
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.
 
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2,556
Location
Columbus Ohio
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.
 
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1,533
Location
Ephraim
Very nice outline! Q:Can a group II be Both Hydrotreated and Hydrocracked? If so what is this Called?
quote:
Originally posted by sbc350gearhead: GII- hydrotreated petroleum base stock. More refined, with less gunk in it. -*-* GIII- "hydrocracked" or severely hydrofinished base stock. Castrol won the right for oil blenders to call this group "synthetic". -*-*
 

Patman

Staff member
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21,988
Location
Oakville, Ontario
quote:
Originally posted by sbc350gearhead: 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.
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??
 

Leo

Messages
911
Location
Australia
Hmmm funny, a while back I emailed Castrol Ausrtalia and they said their GTX3 oil is completely Grp I. And its a SL/A2/A2 & VW 500/505 & MB 229.1 rated oil.. This oil is pretty much the cheapest Castrol oil you can get too.
 

RobWest

Thread starter
Messages
52
Location
Poquoson, VA.
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.
 
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104
Location
Baton Rouge
quote:
Originally posted by sbc350gearhead: 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.
Great outline. What is GII+?
 
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2,768
Location
Tn
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.
 
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1,381
Location
Southeast Kentucky
Rob, I think you'd better put on some insect repellant, you are about to get bitten by the oil bug! [freaknout] 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.
 
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2,233
Location
Wisconsin
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+ ?
 
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4,478
Location
Southern California
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
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21,988
Location
Oakville, Ontario
quote:
Originally posted by hmeyer: Patman wins the prize. 10,000 posts!
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) [Big Grin]
 

RobWest

Thread starter
Messages
52
Location
Poquoson, VA.
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! [freaknout] 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.
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. [Cheers!]
 
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1,533
Location
Ephraim
quote:
Originally posted by Ray H: Group II+ base stocks have a viscosity index range of 110-119. Group III starts at 120. -*-*-*
But these are not set in stone. A group II could have a higher VI right!
 
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