"Never use a non-API certified synthetic oil (there are many of these on the market). The problem with the non-API certified synthetics is that they contain too much phosphorus (in the form of the additive ZDDP (Zinc Dialkyl Dithiophosphates)). The API has limited the amount of phosphorus because phosphorus shortens the life of the catalytic converter. These oils are fine for snowmobiles, motorcycles, and older cars that don't have a catalytic converter, and the extra ZDDP does provide additional wear protection. Unfortunately, the marketers of some the non-certified oils do not explicitly and honestly state the reason for the lack of API certification. You can check the status of API certification on the API web site. Be certain to go not just by the manufacturer name but by the actual product as well. This is because a manufacturer will sometimes have both certified and non-certified products. Suffice it to say that Mobil 1, Royal Purple, Castrol, & Havoline all make synthetic oils that are API certified and that can be purchased at auto parts stores and other retail outlets. Amsoil has one product line, XL-7500 that is API certified, but it's other lines contain too much ZDDP to be certified and should not be used in vehicles with catalytic converters. "
Soo what this says is zddp isan additive you need to prolong engine life. Think of it as a cushion for your engine parts.. however the EPA doesnt like it... but screw them anyway... The EPA doesnt care about your engine internals only trees and grass, even with them getting rid of regular leaded gasoline... we still have just as much polution and global warming.. They might as well bring leaded gas back too... Plus its cheaper to refine and doesnt go to crap after 3 or four months like regular unleaded...
climate does attribute to the best oil in warmer climates 10/40 i recommend penzoil remember in colder climates you should run 10/30 i have been building engines for 20 years and found the best overall outcome with penzoil ,mobil 1 is your best syn oil but the seal tolerances in your engine tend to let oil by them with the detergent in syn oil i would not recommend it .
climate does attribute to the best oil in warmer climates 10/40 i recommend penzoil remember in colder climates you should run 10/30 i have been building engines for 20 years and found the best overall outcome with penzoil ,mobil 1 is your best syn oil but the seal tolerances in your engine tend to let oil by them with the detergent in syn oil i would not recommend it .