The comparison figures provided by Blackstone are not specifically Ford GT results. They have combined results for all Ford 5.4L SC engines regardless of composition or internal components.Hello MTV8, I've had my GT tested ever since I bought mine in 2005, & have had several Blackstone oil tests, done for my car. Don't now what the issue is with the comparison test. I know that is a comment that is old.
But if you send a sample out of of the reservoir and they say it's still good so why change it based on time alone? That's science not "just because".I think oil gets contaminated with corrosives once it is in an engine and it is wise to change it yearly. It is not like storing it in a clean container.
The Total Base Number (TBN) tells you if the oil is becoming acidic. Motor oils have base chemical buffers (as in basic pH) in them to neutralize acids that result from combustion and oxidation of the oil. If the TBN gets too low, that's a reason to change the oil. Blackstone monitors this for extended oil changes (it costs $10 more than the $25 basic analysis, but you definitely want that test if you are extending oil changes like I am).I think oil gets contaminated with corrosives once it is in an engine and it is wise to change it yearly. It is not like storing it in a clean container.