Quote: So is the new formula junk? I'm assuming the last batch I got for my Cummins is likely the new formula. What exactly is the point behind lowering the zinc content? No doubt, some "green" reason.
So, should I use this new formula Shell Rotella in my Road Runner... 440, 11.5 compression, MP solid lifter cam (528 lift I think ), ported heads, MSD, blah, blah, blah. I had been using Royal Purple synthetic, but it is sort of a pain in the butt to get.
Its because of the 'new' 2007 diesel engines (big rigs--Cats and Cummins) and their DPFs (diesel particulate filters). Phosphorus and Zinc contribulte to clogging so they are being reduced.
I'm assuming the last batch I got for my Cummins is likely the new formula. What exactly is the point behind lowering the zinc content? 
), ported heads, MSD, blah, blah, blah. 
I had been using Royal Purple synthetic, but it is sort of a pain in the butt to get. 
