Like one of the earlier contributors, I had purchased an '82 Plymouth TC3 hatchback, stripped w a 4 speed manual, 1.7L Peugot engine, new for ~$2300 incl tax. Oil was changed at 500 mi, then 3500 mi thereafter. Oil consumption was < 0.5 qt between changes. Once mileage reached 10k mi, for the next 10k mi, overall fuel consumption was a consistent 33 to 34 mpg. A can of Arco Graphite was added at 20k mi and every following oil change, and over the next 35k mi, fuel consumption averaged a consistent 35.5 to 36 mpg. So I would conclude that Arco Graphite improved fuel economy 6 to 7%. (What happened after 55k mi? Mona Lou F@#%er, driving a '71 Chrysler Newport, ran a red light in Lima, broadsided the TC3 and gave the TC3 a 360° spin, so testing stopped there.) Up until the accident, the TC3 required no maintenance other than the oil changes and new tires.
In the early 1990s, the US military was evaluating various lubricants that might reduce friction in firearms. One of its studies discussed suspensions containing a fluoropolymer, (likely Tufoil), and the problem of particle size. Think Stokes law. If too small, the particles stay in suspension but will also pass by piston rings. If too large, the particles will fall out of suspension, plugging filters, possibly increasing sludge. or simply settle out in the bottom of the oil pan. The overall lowest friction/ reduced wear/ highest velocity/ highest accuracy ammunition lubricant the military found was,,,,tricresyl phosphate.
And this thread lives on.
