[DangerZL1]

I thought the switch to 0W 40 was to reduce carbon build up on the valves.

[Rock-It Man]

Originally Posted by DangerZL1

I thought the switch to 0W 40 was to reduce carbon build up on the valves.

In general, lowering the upper values is a fuel saving measure. Recommendations went from 40 to 30 and even as low as 20 for some cars. Like all engineering decisions, there are trade-offs. In this case, the trade-off was lubricity during high output driving.

As fo the lower value, there is absolutely no downside to going from 5 to 0, since low viscosity at start-up gets the oil flowing and into gaps more effectively.

But in the end, the most important consideration, for me, is that, given all the variables, which include fits, finishes, and bearing surface materials, the GM engineers know what's best, and not you and me.

[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.

[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

[ZX-10R]

Originally Posted by Rock-It Man

GM engineers know what's best, and not you and me.

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

[DangerZL1]

Originally Posted by Rock-It Man

In general, lowering the upper values is a fuel saving measure. Recommendations went from 40 to 30 and even as low as 20 for some cars. Like all engineering decisions, there are trade-offs. In this case, the trade-off was lubricity during high output driving.

As fo the lower value, there is absolutely no downside to going from 5 to 0, since low viscosity at start-up gets the oil flowing and into gaps more effectively.

But in the end, the most important consideration, for me, is that, given all the variables, which include fits, finishes, and bearing surface materials, the GM engineers know what's best, and not you and me.

I too trust what the GM recommended oil is and see no reason to change in a stock car driven on the street.

[Vigilante375]

All I know is that the Mobil 1 0w40 hasn't shown me any negative effects on my stock ZL1. Plenty of track days in hot weather and plenty of spirited time on the streets.

Neither did the lady who had the 220k mile ZL1 before she sold it to get something more economical. Though she was using mobil 1 5w30.

[Drnick]

Well, that was very informative post!, thanks for all the
Info, this will obviously go down in the annuals of “Another
Oil post”, for future distribution amongst forum members
Next time I’ll just do a poll, instead of asking a question

[ZX-10R]

Originally Posted by Vigilante375

Neither did the lady who had the 220k mile ZL1 before she sold it to get something more economical. Though she was using mobil 1 5w30.

Is this "lady" a member? That has to be near a record...wonder how much oil it used every 5k

Of course she used 5W-30, she didn't buy the rhetoric. It's only been proven for 20 years, the only thing that has changed is this insane fixation on fuel economy ("0" weight oils, which is a lie) or people that naively think you still need to run a 40 weight in a modern engine. Both are equally clueless

[pauly1119]

Originally Posted by Drnick

Well, that was very informative post!, thanks for all the
Info, this will obviously go down in the annuals of “Another
Oil post”, for future distribution amongst forum members
Next time I’ll just do a poll, instead of asking a question

You knew what was going to happen if you asked the question. I think your picture says it all but seriously I don’t know why we try to outsmart the engineers that design our cars but if you try something other then the specs ask for you should send a sample in to Blackstone afterwards and see what the results show. At least then you can have something real and not just google search answers.

[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.

[Vigilante375]

Originally Posted by ZX-10R

Is this "lady" a member? That has to be near a record...wonder how much oil it used every 5k

Of course she used 5W-30, she didn't buy the rhetoric. It's only been proven for 20 years, the only thing that has changed is this insane fixation on fuel economy ("0" weight oils, which is a lie) or people that naively think you still need to run a 40 weight in a modern engine. Both are equally clueless

I don't think so. But her name has come up a few times. She was on a ZL1 Facebook group.

https://ibb.co/ZGt24h8

Of course she ran what GM said and it was the inferior Mobil 1 as well compared to the "vastly" superior Amsoil.

Everyone puts what they want into their vehicles but it just becomes a penis size check when people start to say "Well according to the scientific data from 50 years of (enter oil manufacturer name) that they are better than any other brand".

I have no issues with 0w40 in my car and neither has anyone else. Those LT4s that have a bad oil pump are going to fail no matter what brand of oil is in them nor what viscosity or weight or additives.

[ZX-10R]

Originally Posted by Vigilante375

I don't think so. But her name has come up a few times. She was on a ZL1 Facebook group.

Impressive

Of course she ran what GM said and it was the inferior Mobil 1 as well compared to the "vastly" superior Amsoil.

Everyone puts what they want into their vehicles but it just becomes a penis size check when people start to say "Well according to the scientific data from 50 years of (enter oil manufacturer name) that they are better than any other brand".

I don't think anyone said "vastly" superior - almost all modern synthetics are pretty good - but the data (UOAs and standardized testing) has consistently shown Amsoil is excellent. Probably more important is keeping up with 5000 miles oil change intervals on the street, or less if racing

I have no issues with 0w40 in my car and neither has anyone else. Those LT4s that have a bad oil pump are going to fail no matter what brand of oil is in them nor what viscosity or weight or additives.

Agree

[CW3SF]

I’d say the young ladies data also suggests that Mobil 1 is pretty good as well.