Because a synthetic oil's molecules are much more consistent in size and shape, they are better able to withstand extreme engine temperatures. By contrast, the unstable molecules in conventional oil can easily vaporize or oxidize in extreme heat. Mobil 1 synthetic is said to be capable of protecting engines "at well over 400 degrees F"; in the real world, most racers have no problem running synthetics up to 290 degrees F under prolonged use, but they get really jumpy when a conventional exceeds 270 degrees F.
Because a synthetic oil is chemically produced, there are no contaminants in the oil. By contrast, conventional oils contain small amounts of sulfur, wax, and asphaltic material that can promote detonation as well as varnish and sludge buildup. With no wax, synthetics will flow at much lower temperatures than conventional oils. In fact, synthetic oils are now available with viscosity ratings as low as 0W-30, as in Mobil 1's new Tri-Synthetic blend or Castrol Formula SLX. These oils flow more than seven times faster than a conventional 5W-30 motor oil during initial start-up, yet at normal operating temperatures act like a regular Grade 30 oil.
An 0W-30 synthetic oil is capable of pumping easily at -62 degrees F and flowing at even lower temperatures. Conventional oils are essentially frozen solid at that temperature, so there's simply no conventional equivalent to this new grade. There are 5W-30 conventional and synthetic oils, but even here, the synthetic has a real-world advantage: Mobil 1's 5W-30 will pump at -58-degrees F, compared to about -35-degrees F for a conventional oil.
----2007 Car Craft, a PRIMEDIA publication. All rights reserved. WEB-023
In short....synthetics better withstand the searing temperatures of a turbocharged engine, leave behind fewer (if any) deposits when heated, and flow better in extreme cold temperatures. There's a reason so many performance car manufacturers fill their vehicles with Mobil1 from the factory.
Acura RDX
Aston Martin
All Bentley Vehicles
Cadillac CTS, CTS-V, Escalade, XLR, XLR-V, SRX, STS and STS-V
Chevrolet Corvette C6 and Z06
Chevrolet TrailBlazer SS
Chrysler 300C SRT-8
Cobalt SS S/C Coupe
Dodge Caliber SRT-4, Charger SRT-8, and Magnum SRT-8
Jeep Cherokee SRT-8
Mercedes-Benz AMG Vehicles
Mercedes SLR
Mitsubishi Evolution
Pontiac Solstice GXP
All Porsche Vehicles
Saturn Ion Red Line and Saturn Sky Red Line
Viper SRT-10
Anything good enough for Porsche, Bentley, Aston Martin and AMG is good enough for me.
