The Advantages of Synthetic Oils over Mineral oils

 

Extended oil drain periods

Better wear protection and therefore extended engine life

Most synthetics give better MPG

They flow better when cold and are more thermally stable when hot

Surface-active meaning a thin layer of oil on the surfaces at all times (in ester based oils)

 

 

How Synthetic oils Achieve these Benefits

 

Stable Basestocks

Synthetic oils are designed from pure, uniform synthetic basestocks, they contain no contaminants or

unstable molecules which are prone to thermal and oxidative break down.

Because of their uniform molecular structure, synthetic lubricants operate with less internal and

external friction than petroleum oils which have a non-uniform molecular structure.

The result is better heat control, and less heat means less stress to the lubricant.

 

Higher Percentage of Basestock

Synthetic oils contain a higher percentage of lubricant basestock than petroleum oils do.

This is because multi-viscosity oils need a great deal of pour point depressant and viscosity improvers

to operate as a multigrade.

The basestocks actually do most of the lubricating. More basestocks mean a longer oil life.

 

Additives Used Up More Slowly

Petroleum basestocks are much more prone to oxidation than synthetic oils. Oxidation inhibitors are

needed in greater quantities in petroleum oils as they are used up more quickly.

Synthetic oils do oxidize, but at a much slower rate therefore oxidation inhibiting additives are used up

more slowly.

Synthetic oils provide for better ring seal than petroleum oils do. This minimizes blow-by and reduces

contamination by combustion by-products. As a result, corrosion inhibiting additives have less work to

do and will last much longer in a synthetic oil.

 

Excellent Heat Tolerance

Synthetics are simply more tolerant to extreme heat than petroleum oils are. When heat builds up

within an engine, petroleum oils quickly begin to burn off. They are more volatile. The lighter

molecules within petroleum oils turn to gas and what's left are the large molecules that are harder to

pump.

Synthetics have far more resistance as they are more thermally stable to begin with and can take

higher temperatures for longer periods without losing viscosity.

 

Heat Reduction

One of the major factors affecting engine life is component wear and/or failure, which is often the

result of high temperature operation. The uniformly smooth molecular structure of synthetic oils gives

them a much lower coefficient friction (they slip more easily over one another causing less friction)

than petroleum oils.

Less friction means less heat and heat is a major contributor to engine component wear and failure,

synthetic oils significantly reduce these two detrimental effects.

Since each molecule in a synthetic oil is of uniform size, each is equally likely to touch a component

surface at any given time, thus moving a certain amount of heat into the oil stream and away from the

component. This makes synthetic oils far superior heat transfer agents than conventional petroleum

oils.

 

Greater Film Strength

Petroleum motor oils have very low film strength in comparison to synthetics. The film strength of a

lubricant refers to it's ability to maintain a film of lubricant between two objects when extreme pressure

and heat are applied.

Synthetic oils will typically have a film strength of 5 to 10 times higher than petroleum oils of

comparable viscosity.

Even though heavier weight oils typically have higher film strength than lighter weight oils, an sae 30

or 40 synthetic will typically have a higher film strength than an sae 50 or sae 60 petroleum oil.

A lighter grade synthetic can still maintain proper lubricity and reduce the chance of metal to metal

contact. This means that you can use oils that provide far better fuel efficiency and cold weather

protection without sacrificing engine protection under high temperature, high load conditions.

Obviously, this is a big plus, because you can greatly reduce both cold temperature start-up wear and

high temperature/high load engine wear using a low viscosity oil.

 

Engine Deposit Reduction

Petroleum oils tend to leave sludge, varnish and deposits behind after thermal and oxidative break

down. They're better than they used to be, but it still occurs.

Deposit build-up leads to a significant reduction in engine performance and engine life as well as

increasing the chance of costly repairs.

Synthetic oils have far superior thermal and oxidative stability and they leave engines virtually varnish,

deposit and sludge-free.

 

Better Cold Temperature Fluidity

Synthetic oils do not contain the paraffins or other waxes which dramatically thicken petroleum oils

during cold weather. As a result, they tend to flow much better during cold temperature starts and

begin lubricating an engine almost immediately. This leads to significant engine wear reduction, and,

therefore, longer engine life.

 

Improved Fuel Economy

Because of their uniform molecular structure, synthetic oils are tremendous friction reducers. Less

friction leads to increased fuel economy and improved engine performance.

This means that more energy released from the combustion process can be transferred directly to the

wheels due to the lower friction. Acceleration is more responsive and more powerful, using less fuel in

the process.

In a petroleum oil, lighter molecules tend to boil off easily, leaving behind much heavier molecules

which are difficult to pump. The engine loses more energy pumping these heavy molecules than if it

were pumping lighter ones.

Since synthetic oils have more uniform molecules, fewer of these molecules tend to boil off and when

they do, the molecules which are left are of the same size and pumpability is not affected.

 

Synthetics are better and in many ways, they are basically better by design as they are created by

chemists in laboratories for a specific purpose, rather than being modified from something that came

out of the ground to be as good as they can for a purpose.

 

Cheers

 

Tim

I Tom, how does semi synthetic compare?

So do people actually increase the change intervals when using a fully synth ? I don't think I ever have.

I've used a Castrol part synth 10/40w currently and under certain circumstances, i.e if I've been boosting hard and the engine is HOT some oil passes the exhaust seals and burns in the exhaust. Could my choice of oil be in part to blame, becoming too thin under high temperature's and letting by or am I just looking for an easy fix haha.

I Tom, how does semi synthetic compare?

 

All semis are 100% mineral based (the 'synthetic' part is a modified and refined mineral oil), so a semi is more like a mineral oil than a proper synthetic.

 

Cheers

 

Tim

So do people actually increase the change intervals when using a fully synth ? I don't think I ever have.

 

Yes, a lot of people increase the change intervals when using a synthetic. If a car is using a semi and getting changed at 5k, generally changing at 10k with a synthetic is fine.

 

Cheers

 

Tim

 

- - - Updated - - -

 

I've used a Castrol part synth 10/40w currently and under certain circumstances, i.e if I've been boosting hard and the engine is HOT some oil passes the exhaust seals and burns in the exhaust. Could my choice of oil be in part to blame, becoming too thin under high temperature's and letting by or am I just looking for an easy fix haha.

 

How hot does the oil get?

 

Cheers

 

Tim

That I couldn't tell you, what sort of tempreture would cause issues? only way I can feasible tell is to use my infrared thermometer after a spirited drive.