[R3ctivision]

Hi everyone, first off, I know the manual says to run 15W-50 for track use in the ZLE. That's the only oil I have ever run, since my car only gets street mileage to/from the track on the highway.

But I intend to continue doing some track days in the winter. And that gets me a bit concerned with the oil's thick viscosity on cold morning starts (could be high 30s/low 40s Fahrenheit where I live). I noticed Mobil has a 5W-50 that looks similar to the 15W-50, and is recommended for Porsches and high temperature/high stress applications on their website. Manual and warranty aside, can any oil experts provide some meaningful input in the differences between the two oils and is it something that could be considered for winter track use?

https://www.mobil.com/en/lubricants/...1-fs-x2-5w-50/

[Junkyardspecial]

I feel like it should be ok, but I've used 15w-50 on cold mornings and just let the engine have some idle time before doing any sort of driving.
It does have less additive phosphorus and zinc than the 15w-50, so lower anti wear properties in that regard.

[SFV1LE]

You could use the 5w50, I've considered the same for cold morning winter track days in CA. You could also mix a 50/50 combo of 5w50 and 15w50.

If there's a problem GM may be able to detect the presence of 5w50, so I'm reluctant to run on track.