Quote Originally Posted by miko101130 View Post
i already removed my catalytic converter so i can use all the Zinc there is..haha... another thing DOc, im currently using fully synthetic 5w40, if i use the delvac 15w40 will there be any significant change in fuel consumption? or too little to notice?
Higher ZDDP will give you better fuel economy, but 40 weight oil is 40 weight oil, it's not going to make any measurable difference in 5w40 and 15w40. Whoever got the much ZDDP and moly will have the best fuel economy between the two.

If you have no cat would be looking at just about any heavy duty diesel oil, Like ZIC, Delo, or Top1 all will last a very long time in a gas engine.