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iwilson · 05-16-2005, 08:45 AM

Not all synthetic oil is really synthetic. The old adage you get what you pay for really applies when it comes to oil.

Synthetics can be broadly broken down into three types:

* Group III Hydrocracked:- Derived from normal mineral oil, technically not synthetic, but owing to lawyers getting involved can be sold as such. Lots of it on the market. Not bad stuff, but it's still Dino oil at the end of the day.
* Group IV Polyaphaolefins or POA's:- The real deal, made in the lab by guys in white coats. Mobil 1 is an example or *used* to be - they now mix in some hydrocracked basestock.
* Group V Polyol Esters:- The Rolls Royce of the synthetic world. Provides even better lubrication than POA's. Expensive but worth it if you're caning the engine. Motul, Redline, Amsoil, Silkolene and Royal Purple are examples. I personally use Motul 300V double ester.

The lawyer bit relates to a court case involving Castrol. They changed their formula from a group IV base stock to using group III. Mobil took them to court and unfortunately Castrol won. As a result a lot of companies changed their formula as well. So most of the so-called synthetics on the market today are based on inferior group III base stock. One major short coming of group III oils are their change in viscosity over time. This means for e.g. that a 40 weight oil will turn into a 20 weight oil. This is because group III oil doesn't have good shear resistance - meaning that the molecules get chopped up reducing the rated viscosity of the oil. Group V oils have excellent shear properties and maintain there viscosity for life of the oil. In addition group V oil provides excellent startup protection, lubricity and fuel efficiency. This is due to their attraction to metal surfaces. They are also excellent at preventing sludge and varnishing. Group IV oils are poor in this area and are often mixed with 10/20% group V base stock. Group IV and V oils are thermally more stable with good low and high temperature performance.

I certainly wouldn’t use anything less than a group IV oil, especially if your engine is mainly used on the track.

05-16-2005, 08:45 AM	#3 (permalink)
iwilson Registered User Join Date: Jan 2004 Location: Pukekohe, New Zealand Posts: 484	Not all synthetic oil is really synthetic. The old adage you get what you pay for really applies when it comes to oil. Synthetics can be broadly broken down into three types: * Group III Hydrocracked:- Derived from normal mineral oil, technically not synthetic, but owing to lawyers getting involved can be sold as such. Lots of it on the market. Not bad stuff, but it's still Dino oil at the end of the day. * Group IV Polyaphaolefins or POA's:- The real deal, made in the lab by guys in white coats. Mobil 1 is an example or used to be - they now mix in some hydrocracked basestock. * Group V Polyol Esters:- The Rolls Royce of the synthetic world. Provides even better lubrication than POA's. Expensive but worth it if you're caning the engine. Motul, Redline, Amsoil, Silkolene and Royal Purple are examples. I personally use Motul 300V double ester. The lawyer bit relates to a court case involving Castrol. They changed their formula from a group IV base stock to using group III. Mobil took them to court and unfortunately Castrol won. As a result a lot of companies changed their formula as well. So most of the so-called synthetics on the market today are based on inferior group III base stock. One major short coming of group III oils are their change in viscosity over time. This means for e.g. that a 40 weight oil will turn into a 20 weight oil. This is because group III oil doesn't have good shear resistance - meaning that the molecules get chopped up reducing the rated viscosity of the oil. Group V oils have excellent shear properties and maintain there viscosity for life of the oil. In addition group V oil provides excellent startup protection, lubricity and fuel efficiency. This is due to their attraction to metal surfaces. They are also excellent at preventing sludge and varnishing. Group IV oils are poor in this area and are often mixed with 10/20% group V base stock. Group IV and V oils are thermally more stable with good low and high temperature performance. I certainly wouldn’t use anything less than a group IV oil, especially if your engine is mainly used on the track. Last edited by iwilson : 05-16-2005 at 08:49 AM.