Why are GP III's Bad

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Dec 28, 2003
I know the board does not like Group III's, but logically why not a Group III if the additive package is great and meets GM 4718M as required??

I've heard the Castrol argument ad nauseum, so please don' repeat.

Why not??
Group III oils are fine...it's just the 'ol argument of getting what you pay for. If you can get a better oil for the same price, then why not?
No one said they are bad. Over the long haul you want a grp IV, thats all. Grp III's are fine if formulated well. Shaeffer's dosn't use any grp IV and it's an excellent oil.
How do I know that Mobil 1 with PAO is better than Brand X at a similar price with Group III.

If PAO is only marginally better, and Brand X has a superior additive pack???

Base isn't everything.
This has been beaten to death. I'd do a search on grp III's and read some of it. Also, try doing a UOA for your answer.

Originally posted by buster:
No one said they are bad. Over the long haul you want a grp IV, thats all. Grp III's are fine if formulated well. Shaeffer's dosn't use any grp IV and it's an excellent oil.

THeir is nothing wrong with a well formulated GIII!!!!!! THe problem is that a lot of companys pass these off as being equal to GIV and GV base stocks and they are not! TO make matters worse they charge the same price for them as a GIV or GV oil even though they typicaly cost less then half as much to make!

Most of the GIII bashing is related to Castrol's switch from GIV to GIII while maintaining the same price for the product!

If companys charged a fair price like $2 a quart for GIII oils then they would be a real value and I think most people would praise them! I like to equate it to someone offering to sell you gold but delivering lead instead! The way I understand it lead is very similar molecularly to gold.
JohnBrowning is totally correct. Group III should not cost more than 2 -2.5 dollars/quart. Castrol can go to hell with their marketing strategy (i.e. screwing castormers). Their additive pack is not better than Mobil 1. In fact, my personal opinion is that Mobil 1 has the best addtive pack among all synthetic oil on the US market (and very likely world wide). Besides Castrol is not releasing any data sheets on their oils. How can I trust a company which is not giving info about their product, while everyone else does? How would you like to buy a car without knowing how many cylinders, power, speeds, and etc. it has?

I was thinking about using Castrol's highly praised German imported 0W-30, but now I think I'll stick with Mobil's 10W-30.


. In fact, my personal opinion is that Mobil 1 has the best addtive pack among all synthetic oil on the US market (and very likely world wide). Regards, [/QB]

Pretty strong statement.
I'd like to hear from Redline or Amsoil about this.

Originally posted by buster:
Amsoil clearly doesn't have the best additive package right now.

I won't argue with that because I don't know one way or another. But is it better than Mobil's?

The way I look at it is if Mobil uses "the best additive package", it ought to produce some of the best UOAs on a consistent basis (subject to occasional sampling errors). It has a great base oil (PAO) so there shouldn't be anything holding it back. Yet, it gets outperformed quite a bit by other OTC oils (i'm not even including Redline or Amsoil). Something's gotta be holding it back and I wish somebody would explain to me what it is.

Before I get flamed, I'm not saying Mobil 1 isn't a great oil. If it was the only oil available, I wouldn't lose sleep having it in my engine. But for Titanium to claim it has the "best additive package" is pretty bold.


Not sure what you mean by What? For long extended drains, group IV's hold up better. For shorter drain intervals a well formulated grp II or III is fine. Schaeffer's is not a grp IV oil but shows excellent numbers.
Yes,your are right.The Schaeffer oils we normally talk about are not 100% GRP IV basestock.The blends do have about 15-25% PAO though.
And yes again,they do work well.Sorry for the miscommunication.

I think we forget sometimes that viscosity and grps don't always matter. Schaeffer's obviously has some excellent chemists working for them bc there oils many times outperform the so called best synthetics. Over an extended drain I dont know but they hang with the best of them.
I'm sure you all have seen VOA for a full Mobil 1 line at:

How many of other oils contain all of the following: Boron, Molybdenum, a lot of Calcium. Original VOA for GC showed calcium at 3600 -4000 ppm. Now from UOA we see that it has more like 2500-3000 ppm - lower than Mobil 1. Amsoil and Redline make pretty good oils for sure, but I believe that for economic reasons they just can't afford advanced additive pack and still be profitable (while buying basestocks from the same Exxon/Mobil). I don't think that loading Redline with huge amounts of Molybdenum will do any significant advantage because there is only a certain amount of Mo which can be taken by the engine, the rest is just floatiing around without doing any good. Mobil has also lowerd sinc and phosphorous to prevent damage to cat converter. The only other VOA I've seen which comes very close to Mobil 1 is Silkolene 5w-40, see (no Molybdenum):

I still think that Mobil could have improved their oils by increasing viscosity at 100C to around 11-12. Flash point, NOACK, and other parameters for Mobil lineup look very good already. Besides Exxon/Mobil is probably most used oil in racing all around the world. Exxon/Mobil has money, knowledge, and ability to do constant real life and laboratory testing of their oils and modify products accordinly. SuperSyn additive was introduced in F1 in 1995 or 1996, then steadily migrated into other oils. I wait with a great interest the first VOA's and UOA's for M1 Racing 0W-30 (although I don't know if it will be the best oil for a street driven car).

Amsoil as we know is a blender . Amsoil can only buy what is on the market. Same with Redline and many other small blenders {not a major oil company } Can anyone honestly say the mentioned companies put out a poor or low quality product?

Don't let the Group IV and V boys wear you down. Pick an oil then make it prove itself with analysis.

In the end it all boils down to economics.

Is it better for you and/or your vehicle to use $5.00/gallon oil for 3k, $27.00/ gallon oil for 25k, or something in between.

Any way you go you will need a few analysis to see if your oil is letting you down.

CAUTION: Analysing oil is addicting. But go ahead join our jolly band of brothers. Oil Analyzers Anonimous (OAA). We have an excellent 12 step program.

Let me get you started with a tease. The first step is learning how to draw a sample without contaminating it.
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