Benefits & Data

Scientific testing of SOD-1 Plus

We know that an ester-based additive such as SOD-1 Plus can enhance lubrication performance and bring benefits such as cleaner internal surfaces and longer lifecycles in cars and other machines. But how do you test the qualities in a lubricant on a technical, scientific basis? Essentially there are three different tests recognized by tribology professionals:

  • Kinematic viscosity
  • Shear stability
  • Shell 4-Ball Wear Test

SOD-1 Plus was tested in Japan by two highly qualified professors of mechanical engineering who specialize in tribology:

Professor Noriaki Satonaga
Sojo University, Kumamoto Prefecture
Department of Engineering

Dr Takashi Watanabe
Retired Professor of Engineering,
Kurume Institute of Technology,
Fukuoka Prefecture

A copy of their 2015 report on SOD-1 plus entitled Effects on Tribology of A Reducing Additive for Automobile Lubricant can be downloaded here.

1. Kinematic viscosity

We know that viscosity measures how fast a fluid moves or flows when force or stress is applied to it. Low viscosity fluids move faster than high viscosity fluids. Richard Michell: “ The technical definition of viscosity is the ratio of the shear force or stress that is applied to the fluid (called the rate of strain or shear) to the rate of relative movement of the fluid. But because different fluids have different densities, it’s more accurate to measure kinematic viscosity than absolute viscosity.

This uses a gravitational method to measure the time it takes for a given quantity of the fluid to flow vertically, under gravity, through an orifice or narrow tube. The international standardized unit of kinematic viscosity is mm2 per second.

In testing the kinematic viscosity of SOD-1 Plus, Dr Watanabe and Prof. Satonaga first measured the chemical state of SOD-1 Plus on its own. The result are in Table 1.

Table 1. Oxidation stability test of SOD-1 Plus (JIS K2514)

Kinematic Viscosity 40˚C mm2/s 610.0
Kinematic Viscosity 100˚C mm2/s 92.4
Viscosity Index 243
Pour point -42.5
Flash point (PM) 224
Ash mass% 2.305
Oxidation Stability (ISOT)
Viscosity ratio 1.06
Increased Oxidative mgKOH/g -0.80
Lacquer rating No deposits

Next they added SOD-1 Plus at 10 % volume to fresh engine oil (SN5W-30) and to fresh automatic transmission (ATF) oil. These results of these tests are set out below in Table 2 and Table 3.

Table 2. Effects of SOD-1 Plus on Chemistry of Engine Oil (SN5W-30)

SOD-1 Plus  SN5W-30 SN5W-30 + SOD-1  Progress rate %
Kinematic Viscosity 40˚C mm2/s  610  60.9  77.6 27.4
Kinematic Viscosity 100˚C mm2/s  92.4  10.5  13.5 28.6
Viscosity Index  243  162  179 10.5
FALEX Seizure Load (ASTM) lbs  750  1000 33.3
Hot Tube Test 100˚C  7  8 14.3 
Rubber Swelling Degree vol.%  5.6  8.2 46.4


Table 3. Effects of SOD-1 Plus on ATF Oil Chemistry and Shear Stability (Ultrasonic method, JPI 5S-29-88)

New Oil (ATF) New Oil (ATF) + SOD-1 (7 vol. %) Progress Rate %
Kinematic Viscosity 40˚C mm2/s  33.7 42.2 25.2
Viscosity Index 7.21 8.96 24.3
FALEX Seizure Load (ASTM) lbs 185 200 8.1
Hot Tube Test 289˚C Mark 1.72 1.48 -14.0 
Rubber Swelling Degree vol.% Seizure 0.46
 Shear Stability (Ultrasonic Method)
 Kinematic Viscosity 40˚C mm2/s (Before Test) 33.6 42.0 25.0
 Kinematic Viscosity 40˚C mm2/s (After Test) 30.8 36.3 17.9
 Rate 40˚C % -8.10 -13.6
 Kinematic Viscosity 100˚C mm2/s (Before Test) 7.21 8.97 24.4
  Kinematic Viscosity 100˚C mm2/s (After Test) 6.50 7.59 16.8
 Rate 100˚C % -9.83 -15.4


Summarising the results from these tests we note as follows:

Engine Oil

  • Kinematic Viscosity 40C mm2/s improvement rate with SOD-1 27.4% 27.4%
  • Kinematic Viscosity 100C mm2/s improvement rate with SOD-1 28.6% 28.6%
  • Rubber Swelling Degree vol.% improvement rate with SOD-1 46.4% 46.4%
  • Viscosity index improvement rate with SOD-1 10.5% 10.5%
  • FALEX seizure load improvement rate with SOD-1 38% 38%


  • Kinematic viscosity of the oil improvement with SOD-1 25% 25%
  • Viscosity Index improvement rate with SOD-1 8.1% 8.1%
  • Acid value reduction with SOD-1 14% 14%
  • Post test shear stability kinematic viscosity improvement with SOD-1 16.8% 16.8%

2. Shear stability

Shear stability in a lubricant is its ability to resist changes in viscosity caused by mechanical stress or shear. Exposure to greater rates of shear tends to lower viscosity in some lubricants – as does an increase in temperature – so in the second half of Table 3 above one should compare the pre- and post-test figures for the ATF oil alone and when SOD-1 Plus is added. The result was an increase in kinematic viscosity of 17.9% at 40°C and 16.8% at 100°C.

3. Shell 4-Ball Wear Test

This test measures the friction and wear effect of a lubricant. It is used in tribology laboratories all over the world. The apparatus contains three stationary balls where one rotating ball is pressed against them. Torque, friction, and rotational speed are measured, and when seizure occurs the wear scar diameter is measured. Depending on the quality of the lubricant the wear scar will differ in scale. The smaller the diameter, the better the performance of the lubricant fluid being tested.

Dr Watanabe and professor Satonaga tested SOD-1 Plus using a 5W-30 new oil. Rotational speed was 1200 rpm, a load of 40 Kgf, a temperature of 75°C, and a time of 60 minutes. The wear scar diameter of the oil without SOD-1 Plus was 0.46mm, and with SOD-1 Plus it was 0.33mm, an improvement in lubricity of 28.3%. More details about this test in our Case study section.

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