This is a pretty informative blog site, but I have found what You are referring to.
There was a relationship between NASCAR & Z-Max, but this relationship was
dissolved due to a lawsuit filed by the Federal Trade Commission.
The Commission vote to file the complaint was 5-0. It was filed in U.S. District Court
for the Middle District of North Carolina, in Greensboro, January 31, 2001.
For a full write-up on the subject visit the site below.
http://forum.ih8mud.com/chit-chat-section/259176-psa-stay-away-zmax-engine-treatment.html