TBN is alkalinity, not KOH or CaCO3 -- these are the standards used to calculate the alkalinity, not the materials in the oil -- don't know what those are, but NOT calcium carbonate, it wouldn't dissolve!

When the TBN gets too low, acidic corrosion will start to occur. Short driving distance use without full engine warmup will greatly increase this problem due to water collection in the sump.

Synthetics are better oils, any way you want to measure it, but if you change them at 3000 miles, you are wasting money -- dino oils on that change interval are just as good. Synthetics shine under severe usage and long change intervals.

For diesel use (my own main use), soot levels are more important than anything else -- excess soot causes excess wear, so the oil has to go when the soot level gets up the the max, reguardless of the rest of the analysis results. For gasoline use, new engines run CLEAN -- on some cars, you won't see any visible color change in the oil after 6000 miles. Hard to believe, but true. Engines also last forever now -- my Nasty Nissan (90 Sentra SE with 235,000 miles) uses no oil between changes at 3000 miles (Speedy Oiler) -- leaks a bit, but doesn't burn any). Whoda thought?

RedLine is a distributor of high prices and high quality oils and additives, very reputable, one the order of Amsoil. Probably get their synthetic base from Mobil.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!