BEZ06

I think n8dogg's "will" cause damage is more accurate.

I used 15W50 in the LS9 in my ZR1. I don't know whether it was due to the additional additives in the oil or not, but I had a Cat failure.

They got a new Cat for the right side, but when they installed it found out that the design had changed since my 2009 was built and the new one wouldn't attach to the X-pipe, and I needed a new Cat for the other side and a new X-pipe as well.

My car was out of warranty, so I was expecting a HUGE repair bill, but when I went in I was pleasantly surprised that the bill was $zero.

It turns out that Cats are required by the EPA to be warrantied for 8 years/80,000 miles.

So....I'm sure that GM/Chebie are interested in keeping the Cat replacements to a minimum, and the amount of stuff like Zinc, Phosphorous, Boron, and ash in the 15W50 or 0W40 are not good for the Catalytic Converters.

X25

What I rather get from this thread is that 15W-50 is not good for continuous use, and 0W-40 might be the ticket for us. I used 0W-40 extensively on my various C6 Corvettes, and it held up pretty well. I see no difference for C7. This new track prep doc seems to be creating quite a bit of unnecessary headache.

Dabigsnake

Since we have all the oil Gurus here. What are the maximum temps for Mobil 1 15/50? Does it break down, and need changing, after you reach 300* or so on track, after some hard laps?
So far, this thread tells me in my home/warm climate I can leave 15-50 in if I don't drive 12,000 a year. My car will never be started in any freezing temps.

Bill Dearborn

It is hard to know since it isn't published on the web except as a graph with no numbers. Mobil 1 15W50 has a flash point of 450 degrees which is an excellent number.

Bill