It seems to me that if discount mineral oil can qualify as API SL or ILSAC GF-3, then these tests are a little weak. Amsoil has a page detailing how their 10W-30 oil passed a series IIIF test, and in fact did three times the required time and still passed with flying colors. So theoretically, an oil could just barely pass the basic requirements, but get the same rating as an oil that passed it much more easily. Does anyone know of a test which is so brutal that only the highest quality oils, perhaps only high quality synthetics, can pass?