Do you even know how
AO Gold Member
Join Date: Sep 2007
Location: South Africa
County: Western Cape
A fully synthetics breaks down less due to normal driving (cold starts allowing some fuel to disolve into the oil) and will protect better when the engine is cold. On a 1000 mile journey, when one measures the total damage to an engine in the process, 95% of the damage occures in the first 5 mins after start-up. If your oil protects (it needs to have some viscosity to do this) then you reduce this damage.
Fully synthetics are also able to remain more stable as they heat up. They will not shear and lose viscosity as easily. Modern synthetics have smaller molecular "chains" to prevent shearing of the molecules and reduction in viscosity.
The most important thing about protection is how you treat your engine: If you need your car to be protected from cold, use a synthetic. If you can take a moderate 5 min drive to warm her up before booting it, use a semi.
My comute to work puts me on a motorway 1 mile after leaving home. So I rely on a synthetic to protect my engine. I also enjoy my cars in the mountains over weekends, putting stresses and strains on them, every weekend so I use Edge 10W60 racing synthetic. Never been sorry for doing this, ever. using it for years now, on relatively high milage vehicles, with none of them blowing a single puff of smoke, or using a drop of oil.