JDM MAZDA ENGINE - AN OVERVIEW

Early 12A engines also function a thermal reactor, just like the 0866 10A, and some use an exhaust port insert to lessen exhaust sound. A lean-melt away Variation was released in 1979 (in Japan) and 1980 (in America) which substituted a more-traditional catalytic converter for this "afterburner". A significant modification with the 12A architecture