[ZLRob]

Originally Posted by ZX-10R

Here's the truth: "zero" weight oil is a marketing gimmick, and manufacturers recommending ultra thin oils is a strictly concession to the hyper fuel economy agenda, rather than longevity of your engine

On the flip side, 40+ weight is too heavy for any street engine (and questionable benefit for a race engine). GM's call for 40+ in the Camaro is strictly to mitigate oil starvation during high G loads when cornering with a wet sump. It again has nothing to do with engine longevity and those thick oils are have terrible cold flow properties. Who knows, may be a contributor to oil pump failures

Run 5W-30 or 10W-30 in any engine and you will be fine. Turn off the noise. My brother worked for GM Advanced Vehicle Engineering over 30 years

Dexos is bs, don't worry about it. Amsoil Signature exceeds any standard out there

Originally Posted by arpad_m

These threads always end the exact same way: predictably, someone with experience will try to contribute information that is not a carbon copy of the owner's manual, at which point someone else will appeal to the authority of GM engineering... end of discussion.

In general, corporate engineers have access to way more information than us outsiders, but (apart from a few exceptions) they aren't allowed to make decisions that are best for longevity or performance or user experience, because cost cutting, regulatory pressures, sales targets, quarterly results, shareholder benefit maximization etc. often override design and engineering recommendations.

Thus it's quite plausible that someone can provide germane, sound advice even without access to all the information that GM engineering does. Also, being in the know about engine design details doesn't automatically mean there cannot be others with more expertise outside the company.

BTW I have been using Amsoil Signature 10W-30 oil since the latest round of engine mods as recommended by Ted Jannetty, and never had an issue.

Originally Posted by ZX-10R

Valve coking is a result of oil blowby, oil viscosity has a marginal effect. Running thicker oil for that reason (alone) is another band aid (just like running thicker oil in the 1LE is a band aid for oil starvation for wet sump applications).

Yes - Amsoil Signature 10W-30 is probably the best stuff out there, with countless UOAs and standardized test results to back it up, not just internet opinions

Originally Posted by ZX-10R

GM engineers are constrained by fleet fuel economy goals and cost cutting compromises. They clearly state the *only* purpose of the 1LE high viscosity oil spec is possible oil starvation in a wet sump application. It's a band aid

Don't give a good goddamn what other people in these posts are saying. It's very evident to me who knows what's what and you boys are in the know about things outside of what is stated in the manual. Anyone who tells me to consult with the manual and that the engineers know what's best is an automatic red flag to me.

Do the engineers know what's best? Yeah, they do. Does that mean that they are constrained by pressures outside of their control making them recommend oils that you shouldn't run in your vehicle in order to appeal to this hyper fuel economy crap? Well, yeah, they do. It's always do your homework, and question the question when it comes to this stuff because the engineers don't always have the longevity of your engine in mind when making their documented recommendations.

I read a while ago that oil flow is always better than pressure. That singular statement really spoke to me. 5-30 Amsoil is what I'm sticking to.