good breakdown of oils

[2SShowngo]

http://www.google.com/url?sa=t&rct=j...M5ik-RgC934fOA

[unforgiven]

interesting read

[jameslk55]

Originally Posted by 2SShowngo

http://www.google.com/url?sa=t&rct=j...M5ik-RgC934fOA

Thanks for the post.

[2SShowngo]

well I know there has been a ton of threads about what oil to use, and I went crazy myself trying to decide. Found this in my searches and pretty much made my decision easy. I know a lot of others have questions so if you can look at a graph and pick one that you want to run and know where it stacks up against the others I think that makes it simple.

[bballr4567]

People laugh when I tell them that Pennzoil Ultra is a good oil. This does prove it.

However, Im surprised at how poorly the 5W20s did in comparison to the 5W30s in the same brands. Kind of shocking.

[67motorcat]

Yeah cool info...I've seen this one before.

I have used Mobile 1 5/30 for years in all my vehicles and will continue to do so.

Rated #3 and has a great deal of Moly over some of the others....which prevents scuffing.

GM likes it and so do I.

I have always thought the "special" brands were overrated and over priced.

[bballr4567]

Originally Posted by 67motorcat

Yeah cool info...I've seen this one before.

I have used Mobile 1 5/30 for years in all my vehicles and will continue to do so.

Rated #3 and has a great deal of Moly over some of the others....which prevents scuffing.

GM likes it and so do I.

I have always thought the "special" brands were overrated and over priced.

The only issue with Mobil 1 is their protection in direct injection engines. Its just not as good there because the oil quickly and easily gets diluted with fuel. Once the LT1 moves through the lineup I'd be wary.

[67motorcat]

Originally Posted by bballr4567

The only issue with Mobil 1 is their protection in direct injection engines. Its just not as good there because the oil quickly and easily gets diluted with fuel. Once the LT1 moves through the lineup I'd be wary.

This statement makes absolutely no sense at all.....so Oil's other than Mobil1 do not get diluted?

Direct injection would make little difference over port injection anyway.

All oils become diluted over time anyway,especially old school carburated engines during warm up(full choke) getting the cylinder walls washed down....hence Oil changes...

Here is the list for all Dexos approved oils for use in all GM vehicles including Camaro V-6 direct injection,etc.
http://www.gmdexos.com/licensedbrand...sedbrands.html

[JohnnyBfromPeoria]

Originally Posted by bballr4567

The only issue with Mobil 1 is their protection in direct injection engines. Its just not as good there because the oil quickly and easily gets diluted with fuel.

I'm not seeing any correlation. Care to explain? How/why would a direct injection engine dilute its oil any faster than a "conventional" engine?

John B.

[bballr4567]

Its actually quite simple. A regular injection usually has a PSI of 40-80. A DI engine has a PSI of up to 15,000. The fuel in a regular injection engine does not become atomized by the pressure so its in much bigger molecules. In a DI engine, the fuel becomes atomized and the oil literally absorbs the fuel. Think of it as like boulders vs sand. Of course, that is the small breakdown of it. If you dont believe me do your own research. If you think that a DI engine doesnt make that much difference in an oil then you really need to read and read some more. Its a very different animal in a lot of ways.


Look on BITOG.com for DI engines that use M1 oils. It becomes diluted in as little as 3500 miles and quickly falls down the viscosity rating chart. There are some UOAs that show the oil has more than 2% fuel in it. Not good at all.

[The_Blur]

Originally Posted by bballr4567

Its actually quite simple. A regular injection usually has a PSI of 40-80. A DI engine has a PSI of up to 15,000. The fuel in a regular injection engine does not become atomized by the pressure so its in much bigger molecules. In a DI engine, the fuel becomes atomized and the oil literally absorbs the fuel. Think of it as like boulders vs sand. Of course, that is the small breakdown of it. If you dont believe me do your own research. If you think that a DI engine doesnt make that much difference in an oil then you really need to read and read some more. Its a very different animal in a lot of ways.


Look on BITOG.com for DI engines that use M1 oils. It becomes diluted in as little as 3500 miles and quickly falls down the viscosity rating chart. There are some UOAs that show the oil has more than 2% fuel in it. Not good at all.

It sounds like the same test would have to be conducted using all the oils again on DI engines. It's amazing. Automotive enthusiasts have been arguing about oils for decades, and a great study comes out just as those types of engines become obsolete.

[Mouse6.2]

The true test to determine which oil is best for you and your vehicle is to have a used oil analysis (UOA) accomplished on the oil. Everyones driving style, geographical location, fuel used is different and so this all comes to play on how the oil will protect. It isn't all cut and dry from a simple virgin analysis of an oil. There are tons of other factors to consider.

One individual I know has run the 5W30 Chevron Supreme conventional, API SN = 100,011 psi and at 500 miles did a UOA and it already sheared down to a 20w oil, in just 500 miles of use.

For the most part, the average person could care less and does not keep their vehicle long enough, so what oil is used is pointless.

Again, if you really want to know what works best in your vehicle get a UOA.

[bballr4567]

Originally Posted by The_Blur

It sounds like the same test would have to be conducted using all the oils again on DI engines. It's amazing. Automotive enthusiasts have been arguing about oils for decades, and a great study comes out just as those types of engines become obsolete.

Quite honestly, DI engines need to have completely different oils designed for them just like diesels have. The oils just dont preform good when compared to a regular injected gas engine. Its best to just throw the book out when comparing the two engines and what oil to use. Some of the UOAs are downright scary on the DI engines.

Trust me, I had used M1 in our '10 Terrain with the I4 until I saw a UOA done with it. Down right scared me to run the oil for more than 3500 miles. IIRC, the one that changed my mind was a 3.6 DI in an Enclave that had 4k miles on the oil and it had sheared from a 5W30 to a 0W10 and had a distinct odor of fuel and even caught on fire when the owner took a flame to the dip stick.

[JohnnyBfromPeoria]

Interesting. I had a used oil analysis done on my LFX after running the Mobil 1 5W-30 synthetic for 8,000 miles. They said to try 9,000 miles next time and to resubmit. But they're just Blackstone Labs and they probably didn't try to light the dipstick on fire, instead, using some sort of analysis techniques and equipment.

By the theory proffered above, ANY engine oil would fail in a DI engine in no time flat. So, why isn't that happening? Perhaps because the engine isn't pressurizing the cylinder much more than the combustion event (not even close) and the extremely high pressure in the fuel rail is only necessary to get the fuel into the cylinder during compression anyway.

I just need to see more about this to completely wrap my head around it, not that I'm completely discarding the theory. Aren't diesel engines DI, and don't they run much higher compression than any gasoline engine?

John B.