trc vs. mobile 1 oil
Is that a joke? Can you please sight EXACTLY what about the M1 suggested fill engines is different than the other engine built on the same platform. Is it bearing clearances, materials? What about the engine is "designed for M1"?
GM does not design their engines to work with any particular brand of oil. They do have a long standing MARKETING AGREEMENT with M1, back in the LT1(first of the M1 factory fill) days used oil analysis showed M1 was a mediocre choice for them because of consistently high iron wear numbers.
Now formulas do change and different engines do favor different formulas so that is not to say that all M1 in all engines has the same result.
The OP should do like dr_whigham suggested and go over to Bobistheoilguy because all you are going to get here is more ignorant marketing based brand loyalty like wildcamaro and l 95 Trans Am l had to offer.
We can TEST how an oil is actually working in our particular application with Used Oil Analysis. It is cheap enough that if it makes you confident lengthening your drain interval a little it will pay for itself easily not to mention just having MEASURED DATA on how your expensive synthetic oil is actually working.
The LT1 M1 factory fill was because GM didn't want to package an oil cooler into the car and didn't feel like suggesting the dino oils we had available 20 years ago without an oil cooler.
These days DEXOS is a purely CAFE thing it is not what is better for the engine it is a miniscule amount better for fuel economy.
