I know there are plenty of oil posts on the forum but just wondering why the ACEA oil specification is rarely mentioned or is it a given and people generally understand what they need?
When i first got my S14a I did a lot of research on oils to use and Castrol Edge 5W/40 came up a lot (engine is high mileage and used for spirited road use) and as the previous owner had been using Shell Helix Ultra 5W/40 I assumed the Castrol equivalent would be ok so used that, I remember looking in the car manual at the time and there was some old oil specification code I didn't recognize so didn't pay too much attention to that. To be fair the car has been running like a dream, we recently upgraded to a large turbo to support 500+ bhp but as we haven't done internals yet we're boost limited to 1.1 bar at around 370bhp
However I've been looking into ACEA oil specifications again as its due for an oil change and I'm out of Castrol Edge and I noticed that the Castrol Edge is in fact ACEA C3 whereas the Shell Helix Ultra 5W/40 is ACEA A3/B3. Its funny but I rarely see mention of the ACEA oil specification when people are asking for oil advice and even on Amazon where I bought the oil this isn't even mentioned, but from reading up as i understand it ACEA C3 is low saps designed for “catalyst friendly” specifications such as a turbodiesel car with a DPF whereas ACEA A3/B4 is designed for conventional petrel engines like mine
If the ACEA oil specification is important why is it so rarely mentioned?