Project Farm tests to determine if Richard Petty era STP Oil Treatment from 1981 is better than the formula of STP sold today. Each is tested for cold oil flow, thermal breakdown, and lubricity.
The products were also tested by an independent oil testing lab for viscosity, anti-wear additive content, detergent/dispersant levels, and total base number.
Finally, a blend of the vintage and new STP was used in a small engine that smokes badly and has a bad knock.
A big “thank you” to Matt from the LsxMatt YouTube channel for sending the vintage STP to for testing.