I’m running Redline 10w40 in an ’03 Civic to determine if it can produce similar results to my Honda bike. As part of the test, I’m checking TBN to see if the oil can go the distance. The owners manual recommends 5/10 kmiles for OCIs depending on severity of usage. TooSlick’s famous formula yields 13k miles as a starting point for Amsoil OCIs for this car. Here's the last UOA for reference. http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000842 So the engine has now put a bit over 10k miles on this oil interval and here are the TBN numbers.
code:I only have 4 more Dexsil kits so at 13k miles I'm dumping the oil and getting a full UOA (AV lube).Miles on oil TBN (Dexsil) 3366 9 4860 7.5 6766 7 8144 5 9117 5.5 10171 4.75