Deep in another thread, Titanium_Alloy posted:
quote:Question: has Redline ever been tested using the HT/HS method used by Mobil or Amsoil? Or is there a way to correlate? Mostly I'd like to know if Redline 5W-30's quoted HT/HS of 3.8 is greater than 3.5 on Mobil's HT/HS scale! Thanks, Jason
Redline actually uses a different HTHS viscosity testing method, thus Redline's number for HTHS can not be compared to Mobil's or Amsoil's. Mobil and Amsoil use bearing testing method which I think is more accurate and has a direct relationship to the actual oil performance in the engine, while Redline uses Tapered-Plug method. Interesting to note that both of these tests are accepted for API oil classification along with ASTM D5481.