Zinc oil supplement

I add 5 ounces of "Oil Extreme" to my oils. It has a huge amount of microscopic Calcium Carbonate and a TBN of 320. Most oils TBN is in the 10 to 20 range.

David Visard uses it in his slider cam engines....

Spendy but it has boosted my MPG from 22 MPG to 26 MPG in my Subaru Outback XT turbo.