Originally Posted By: civic09
I see and thanks for the info Gokhan. I may try some mobil 1 5w20, as whats the diff between mobil 1 syn and the EP?
thanks in advance
adam
Mobil 1 Extended Performance (as opposed to regular Mobil 1) has Mg detergents in addition to the Ca detergents. With Mg detergents, TBN stays high longer (more mileage), and TBN is what prevents oil from becoming acidic and damaging the engine. It's the same story with Castrol Edge.
Another way of extending the oil life is to increase the starting TBN, to 12 or more by putting more detergents. This is done especially with certain ACEA categories (European oils). But there are limits to metal-compound content (ash limit) in API and many ACEA categories, and for that reason, this may not always be possible.
Basically there are three things that extend the oil life: (1) quality synthetic base oils, (2) TBN retention (Mg helps in that respect but there are also some concerns on possible increased wear with Mg), and (3) the initial TBN (which can be limited by the ash limit).