AMSOIL Signature Series Synthetic Motor Oil Outperforms Competition In New Study

Nine synthetic motor oils were compared to AMSOIL Signature Series 5W-30 Synthetic Motor Oil (ASL). When it was all said and done, Signature Series demonstrated the best overall performance and cost-effectiveness.

Since AMSOIL introduced the first synthetic motor oil to meet American Petroleum Institute (API) service requirements in 1972, many other synthetic motor oil brands have been introduced. Today, synthetics are widely viewed as superior to conventional motor oils, and demand continues growing, but how do other brands compare to AMSOIL?

A Study of SAE 5W-30 Synthetic Motor Oils

Signature Series 5W-30 Synthetic Motor Oil and nine other synthetic oils were subjected to five industry tests conducted according to American Society of Testing

and Materials (ASTM) methodology. The overall annual cost of each oil wasalso compared. The study includedsynthetic motor oils exclusively for a number of reasons.

First, most motorists now understand that synthetics provide increased performance benefits compared  to conventional oils, so convincing consumers of synthetics’ superiority is less of an issue. Second, while conventional motor oil sales remain flat, demand for synthetics continues to increase. Third, testing only synthetics facilitates an apples-to-apples comparison.


Testing examined several important areas of motor oil performance, including resistance to deposit formation, wear protection, high-temperature stability, resistance to acid formation and cold-temperature performance.

Each oil was subjected to the following

AST M test methodologies:


  • Thermo-Oxidation Engine Oil Simulation Test (TEOST, ASTM D 6335)
  • NOACK Volatility Test (ASTM D 5800)
  • Four-Ball Wear Test (ASTM D 4172 Mod.)
  • Total Base Number (ASTM D 2896)
  • Cold Cranking Viscosity (ASTM D 5293)

Test results published in A Study of SAE 5W-30 Synthetic Motor Oils describe and represent properties of oils that were acquired from November 2012 to December 2012.

Candidate Oils

The following nine oils were selected for the study:

  • Castrol Edge® with Titanium Fluid Strength Technology®
  • Lucas Synthetic
  • Mobil 1™ Extended Performance
  • Pennzoil Ultra™
  • Petro-Canada SUPREME Synthetic™
  • Quaker State Ultimate Durability™
  • Red Line High Performance Motor Oil
  • Royal Purple High Performance Motor Oil
  • Valvoline SynPower® Full Synthetic Motor Oil

All oils are 5W-30 viscosity and recommended for applications requiring API SN/ILSAC GF-5 specifications.


AMSOIL Signature Series Synthetic Motor Oil displayed the best results in the Four-Ball Wear, Total Base Number and Cold Crank Viscosity Tests. Results in the NOACK and TEOST Tests were also impressive, proving Signature Series Synthetic Motor Oil’s excellent high-temperature performance. Other oils performed well in some tests, but

not as well in others, illustrating the challenge inherent in formulating a high-quality motor oil that performs well in tests designed to assess optimum engine protection and life. In addition to delivering outstanding performance, Signature Series Synthetic Motor Oil provides maximum cost-effectiveness – even at retail pricing. Because they buy at wholesale, Dealers and Preferred Customers receive even more value. In the end, no other oil demonstrated itself capable of providing the overall performance in these tests and cost-effectiveness of Signature Series.

Total Base Number

Total Base Number (TBN)Performed by an independent, third party lab FEB 2013 The higher the value, the better the performance in the test (Controls Acid Formation)


Four-Ball Wear Test (ASTM D 4172) Performed by independent, third party lab FEB 2013 The Smaller The Wear Scar, The Performance In The Test Controls Friction


Cold Crank Viscosity (ASTM D 5293) Performed by independent third party lab FEB 2013 The Lower The Value, The Better The Performance In The TestHelps Engines Start Easier


NOACK TEST (ASTM D 5800)Performed by independent, third party lab FEB 2013The lower the value, the better the performance in the test Determines Evaporation Loss of Oil