[20Bluezl1]

So before I modded my Zl1 I used Mobil 1 0w-40. My tuner recommended I switch to AmsOil 15W-50 for track and street. I dont daily my car only hard backroads and track.

My question is I'm getting mixed reviews on why I'm using
15W - 50 that I don't need to and I can go back to Mobil 1 0w-40 or try Motul x-clean gen 2 5w40.for yrackand street.

What are guys using?

[Spaceme1117]

I think most are using Mobil 1 ESP 0W40 as this is the recommend oil for the engines in the C7 Corvette. Our cars have the same engines.

15W50 is too thick for everyday driving and is only recommended for the track where oil temps will get 40 to 50 degrees hotter and so the oil thins out more.

From Mobil 1 website:

"Mobil 1™ ESP Formula 0W-40 is the first and only dexos™ approved motor oil developed specifically for Chevrolet Corvettes. It is recommended for all C7 Corvettes* for both track and street use.

*Note the C7 ZR-1 uses Mobil 1™ 15W-50 on the track."

My tuner told me that a friend of his was tracking his C7 ZR-1 and forgot to change the oil to 15W-50. When the oil got hot (250 F temps), the car went in limp mode. The oil got so thin that the cam phaser system was not able to advance or retard the cam like the ECU was commanding. 15W-50 oil fixed that.

[Elite Engineering]

We have covered this several times, but here it is again for some members


20Bluezl1
Your tuner is correct. Listen to him and ignore the "keyboard experts". For the street a 5w or 0w40-50 is best. The rod bearing and subsequent engine failures in the first years were mainly from using the thin oils. Why does GM and others state such thin oils? This is ONLY to meet the CAFE fuel economy standards to avoid the gas guzzler taxes and has NOTHING to do with what's best for the engines protection. That's why GM has made several TSB's on oil weight since the GDI V8's were released. Just go back a few years here and see all the threads on engine failures.

As ALL GDI engines experience many times the raw fuel washdown past the rings than the old port injection engines they replaced. In fact 8-12 times is average. This raw fuel washes oil from the cylinder walls as well as dilutes the oil to say a 0w5 viscosity over time and that wont protect these engines. In fact at 5% dilution engine oil is considered condemned, and most GDI engines reach this in only a few thousand miles, and consumers are kept in the dark.

Why is this? Well the port injection fuel systems sprayed the fuel to mix with the air charge in the port where it was mixed with the air before being drawn into the cylinder during the intake stroke at 45-55 PSI, and the GDI engine sprays in directly into the cylinder at 1,000-3,000 plus PSI and near the top of the compression stroke. That is what pushes so much raw fuel past the rings. As Spaceme1117 correctly pointed out, this causes VVT timing issues as the phasers cannot react quick enough and/or hold the cam positions as commanded. The other issue is all GDI engines experience many times the amount of abrasive particulate matter contamination as intake valve coking deposits shed. While most is expelled harmlessly out the exhaust, some of the smaller particles are pushed between the piston and cylinder walls not only scouring the skirts and walls and rings, but also adds to the contamination load the oil has to deal with.

So, there are dealers who are told the thin oil is for "tighter clearances", which is not accurate, engines cannot go to tighter tolerance's without failures. And any builder can pull up the clearances on rod and mains and see this.

Why are the owners told to switch back to light viscosity for the street? They have to as the averages for MPG are based on the thin oils when the testing was conducted. If they told people the engine would be far better protected to run a 5w50 or for warm climates, a 5w50 all the time it would disqualify that fuel economy certification and it would be a mess with regulators. Why don't most oil analysis's show accurate fuel dilution level's? Only if the oil is drawn from the dipstick tube will it have accurate fuel levels. When drained and capturing the oil while it flows out the drain most fuel, at that temperature (well over 200*F) evaporates and is lost in the sample.

What can be done?

Run ONLY a good full synthetic oil, and the (5w50 is what I see the best protection on these for overall use, 15w50 for track use) will deal with the fuel dilution much better.

Our E2, E2-X and E2-X Ultra systems are designed just for these issues. Here is an example of one of the largest and most respected synthetic lubrication labs in the World running oil in a GDI engine until fuel dilution is close to condemned status. Then a sample is drawn. Then our E2-X system was installed and another 3k or so miles driven and another sample drawn. Even though the oils fuel dilution was close to 5%, running our system actually removed some of this and brought the fuel dilution down so viscosity actually increased again:
https://hosting.photobucket.com/imag...MG_2615_1_.JPG

Now that is under a lab setting and drawing samples through the dipstick (these are available at many parts suppliers including Amsoil) so here is another done independently by a Ford Tech (brand of engine means nothing, this affects all GDI engines, and a twin turbo modified and pushed like this example creates far more blow-by contamination than a easy driven daily). Note the miles and the lab techs comments:
https://hosting.photobucket.com/albu...ps7l9mvzrs.jpg

Or you can change oil every 1000-2000 miles, but that gets pricey and does not address these issues full time like our system does. In fact Light fleet owners install these just for the savings on oil changes and the improved fuel economy from less knock retard pulling timing.

Questions? Ask here or always be aware our Engineering and Technical Support Department is pretty prompt for any questions you may have on any part of today's engines: Tech@EliteEngineeringUSA.com for sales: Sales@EliteEngineeringUSA.com

Cheers!

[20Bluezl1]

Originally Posted by Elite Engineering

We have covered this several times, but here it is again for some members


20Bluezl1
Your tuner is correct. Listen to him and ignore the "keyboard experts". For the street a 5w or 0w40-50 is best. The rod bearing and subsequent engine failures in the first years were mainly from using the thin oils. Why does GM and others state such thin oils? This is ONLY to meet the CAFE fuel economy standards to avoid the gas guzzler taxes and has NOTHING to do with what's best for the engines protection. That's why GM has made several TSB's on oil weight since the GDI V8's were released. Just go back a few years here and see all the threads on engine failures.

As ALL GDI engines experience many times the raw fuel washdown past the rings than the old port injection engines they replaced. In fact 8-12 times is average. This raw fuel washes oil from the cylinder walls as well as dilutes the oil to say a 0w5 viscosity over time and that wont protect these engines. In fact at 5% dilution engine oil is considered condemned, and most GDI engines reach this in only a few thousand miles, and consumers are kept in the dark.

Why is this? Well the port injection fuel systems sprayed the fuel to mix with the air charge in the port where it was mixed with the air before being drawn into the cylinder during the intake stroke at 45-55 PSI, and the GDI engine sprays in directly into the cylinder at 1,000-3,000 plus PSI and near the top of the compression stroke. That is what pushes so much raw fuel past the rings. As Spaceme1117 correctly pointed out, this causes VVT timing issues as the phasers cannot react quick enough and/or hold the cam positions as commanded. The other issue is all GDI engines experience many times the amount of abrasive particulate matter contamination as intake valve coking deposits shed. While most is expelled harmlessly out the exhaust, some of the smaller particles are pushed between the piston and cylinder walls not only scouring the skirts and walls and rings, but also adds to the contamination load the oil has to deal with.

So, there are dealers who are told the thin oil is for "tighter clearances", which is not accurate, engines cannot go to tighter tolerance's without failures. And any builder can pull up the clearances on rod and mains and see this.

Why are the owners told to switch back to light viscosity for the street? They have to as the averages for MPG are based on the thin oils when the testing was conducted. If they told people the engine would be far better protected to run a 5w50 or for warm climates, a 5w50 all the time it would disqualify that fuel economy certification and it would be a mess with regulators. Why don't most oil analysis's show accurate fuel dilution level's? Only if the oil is drawn from the dipstick tube will it have accurate fuel levels. When drained and capturing the oil while it flows out the drain most fuel, at that temperature (well over 200*F) evaporates and is lost in the sample.

What can be done?

Run ONLY a good full synthetic oil, and the (5w50 is what I see the best protection on these for overall use, 15w50 for track use) will deal with the fuel dilution much better.

Our E2, E2-X and E2-X Ultra systems are designed just for these issues. Here is an example of one of the largest and most respected synthetic lubrication labs in the World running oil in a GDI engine until fuel dilution is close to condemned status. Then a sample is drawn. Then our E2-X system was installed and another 3k or so miles driven and another sample drawn. Even though the oils fuel dilution was close to 5%, running our system actually removed some of this and brought the fuel dilution down so viscosity actually increased again:
https://hosting.photobucket.com/imag...MG_2615_1_.JPG

Now that is under a lab setting and drawing samples through the dipstick (these are available at many parts suppliers including Amsoil) so here is another done independently by a Ford Tech (brand of engine means nothing, this affects all GDI engines, and a twin turbo modified and pushed like this example creates far more blow-by contamination than a easy driven daily). Note the miles and the lab techs comments:
https://hosting.photobucket.com/albu...ps7l9mvzrs.jpg

Or you can change oil every 1000-2000 miles, but that gets pricey and does not address these issues full time like our system does. In fact Light fleet owners install these just for the savings on oil changes and the improved fuel economy from less knock retard pulling timing.

Questions? Ask here or always be aware our Engineering and Technical Support Department is pretty prompt for any questions you may have on any part of today's engines: Tech@EliteEngineeringUSA.com for sales: Sales@EliteEngineeringUSA.com

Cheers!

Thank you for your suggestion so im safe with using 15W-50 for hard street backroads and track? By the way I love my E2-X ultra

[Elite Engineering]

Absolutely. Better protection and far better at dealing with the raw fuel dilution, etc.