Quote:
Originally Posted by N Camarolina
3) Our LT1 engines are supposed to use low SAPs oil, thus the Dexos2 specification. Dexos2 calls for phosphorus levels to be 700-900. Supercar 5w-50 appears to have 1100 or 1200 (see Hagler's post #45 of this thread), which seems to exceed the Dexos2 limits and is only about 100 points less than the old M1 15w-50 which GM says is no good for our Cats.
So are we sure the Supercar 5w-50 is actually safe for our Cats?
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Hmm maybe not; there is a note on the Supercar oil spec page that says "Catalytic converter compatibility (only applicable for Mobil 1™ Supercar 0W-40)". Of course the C8 Z06 must have catalytic converters...I wonder if they're somehow designed differently to tolerate this oil or if GM just figured warranty replacement of the catalytic converters for those who drive a lot into the car's cost.
https://www.mobil.com/en/lubricants/...supercar-5w-50
Also it seems that they just did a find and replace for Dexos2 to DexosR when updating the 2022 Camaro owner's manual to the 2023 version. Apparently DexosR allows a higher phosphorus limit since Supercar 5W-50 is DexosR but I doubt the catalytic converters were changed on the Camaro for 2023.
"Alternatively, larger quantities of volatile phosphorus contained in ZDDP have been linked to premature poisoning of the catalyst surface of three-way catalytic converters and is a primary reason phosphorus has been limited in certain oil specifications."
http://www.winnipegsynthetics.ca/art...ps_levels.html