New catalytic converters and ESP Mobil 1
 

Questions on the ZR1 forum involve oil use. Mobil 1 ESP 0w40 for street and 15w50 for track. Is the C7 CAT a better “trap” than what was on the C6? Will extensive track use of higher zinc 15w 50 plug the CAT? We all know zinc aids in lubricantion. What is the advantage to the new oil with less of it?

ESP is a Dexos2 oil, so low ash content or SAPS as the diesel guys refer to. https://mobiloil.com/en/motor-oils/mobil-1/mobil-1-esp

ESP is better on gas (and diesel) converters (and DPFs) due to its low ash. Dexos2 oils and other "euro" formula oils typically have a SAPS content of 0.8 or lower. GM's small diesels in the US use Dexos2 oils

Zinc content for Mobil 1 ESP Formula 0w40 (GM spec'd oil) is 990ppm https://mobiloil.com/~/media/amer/us...pecs-guide.pdf

For comparison, 15w50 Mobil 1 is 1300ppm on zinc. Ash is 1.21. I would imagine that real long term use might have an effect on a C7's converters, hence why the change of oil spec, and also GM's noting of changing the oil back to 5w30 Dexos1 after a track day event. To prevent damage to the catalysts. High ash+high zinc + track use only and drain afterwards. ESP Formula solves that problem.