C1 or C4 are both low-SAPS oils compatible with gas and diesel engines - source:
https://www.oilspecifications.org/acea.php
ACEA C1 Stable, stay-in-grade Engine Oil with
Lowest SAPS-Level, intended for use as catalyst compatible Oil at extended Drain Intervals in Vehicles with all Types of modern Aftertreatment Systems and High Performance Passenger Car & Light Duty Van
Gasoline & DI Diesel Engines that are designed to be capable of using Low Viscosity Oils with a minimum
HTHS Viscosity of 2.9 mPa*s.
ACEA C4 Stable, stay-in-grade Engine Oil with
Low SAPS-Level, intended for use as catalyst compatible Oil at extended Drain Intervals in Vehicles with all Types of modern Aftertreatment Systems and High Performance Passenger Car & Light Duty Van
Gasoline & DI Diesel Engines that are designed to be capable of using Oils with a minimum
HTHS Viscosity of 3.5 mPa*s.
Unfortunately, here in the States we do not have such oils; I spent many hours searching but found nothing. I want to use this oil because I know a number of people in Europe using C1/C4 oils in their Q50's with the same engine with great results to the point that they don't even run a catch can on their cars. Another reason I want to run this kind of oil in my Infiniti is because of what I went through with my Kia. Unfortunately, I don't have a picture, but the intake valves were just filthy after Valvoline 5W30 Advanced that I've been using since 2018. I don't want to deal with anything similar on my Infiniti.
Let's see - Mobil 1™ ESP 0W-30 (
https://www.mobil.com/en/lubricants/for-personal-vehicles/our-products/products/mobil-1-esp-0w-30/)
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Sooo, how's 800 phosphorus and 900 zinc is considered a low-SAPS oil? It clearly says C3 spec, and C3 is:
ACEA C3 Stable, stay-in-grade Engine Oil with
Mid SAPS-Level, intended for use as catalyst compatible Oil at extended Drain Intervals in Vehicles with all Types of modern Aftertreatment Systems and High Performance Passenger Car & Light Duty Van Gasoline & DI Diesel Engines that are designed to be capable of using Oils with a minimum HTHS Viscosity of 3.5 mPa*s. (Source:
https://www.oilspecifications.org/acea.php)
The same applies to Pennzoil Platinum Euro L 5W30; it falls under C3 oils (
https://www.shell-livedocs.com/data/published/en-US/164b290d-20a3-42b0-b40b-fdbdfaa8965d.pdf)
I don't understand why you think this is "overkill" when low-SAPS oil clearly provides more good than harm. I may even run it in my Kia since our beloved Valvoline Advanced just cakes on its valves. I don't want to deal with CD issues in my Infiniti.