. [/quote]
He's referring to a few points. I'll see if I can help a bit here. When Turbo Gas Direct Injection (TGDI) engines were initially introduced, manufacturers quickly discovered that the engine would exhibit Low Speed Pre-Ignition (LSPI) and it was creating a situation that could damage the engine. After a fair amount of research they realized that a) different additives in oil (mainly calcium) were creating an environment that would promote LSPI and, b) they could reduce/eliminate LSPI by going to multiport fuel injection.
Calcium and Magnesium are commonly added to oils to help keep the engine clean, but at the same time too much calcium creates an environment for LSPI in TGDI engines. Once manufacturers realized this they reduced the amount of calcium used and increased the amounts of magnesium. If you have a look at a number of virgin oil analysis with SN-Plus rated oils, you'll see that they're very similar in the overall composition. Sure they'll vary a little bit here and a little bit there, but for the most part they all keep the calcium levels below 1400 ppm and have higher levels of magnesium.
The reference to Quaker State Ultimate Durability (QSUD) 5w30 being on the thicker side of a 30, is a reference to the fact that oils have a viscosity range that they can be in, and still be considered within grade. This is indicated by the cSt viscosity.
In your last oil analysis you can see the cSt viscosity range for the 5w40 is between 11.6-15.3. You can also see that the Castrol Edge 5w40 had fallen out of grade and was sitting at 10.xx. Essentially this means that your 5w40 had sheered down to a 5w30 grade oil. This is likely due to fuel dilution.
Since there is a grade range for oils you can have some oils on the thin end of the spectrum and some oils on the thick end of the spectrum. QSUD 5w30 is on the thicker end, while other oils such as Pennzoil Platinum 5w30 is on the thin end. Regardless of where they fall on the spectrum, they're both still considered 5w30. This has implications for the oil in TGDI engines because they tend to be hard on oil and can sheer them down a grade or so. No one can really predict exactly how much an oil will sheer down during use because it depends on a number of factors so some combat this by selecting oils on the thick end of the spectrum, or move up a viscosity grade altogether and let it sheer down.
When it comes to fuel dilution, Blackstone Labs does not have the equipment to be able to accurately measure the levels of fuel within your oil. They use a method that estimates the % of fuel dilution and many people here argue that it's not accurate. At all.[/quote]
Thank you for that good information. I will look into that oil. Also for now I will have to stick with Blackstone because I still have six more of their containers that I don't want to just throw away and be wasteful.
I'll be taking an oil sample right now with the mobile 0-40 oil and we will see how well it has done in this engine. I'm also changing the oil pan because I have that one year where Ford used plastic oil pans and it's leaking ...¡.
