Oil confusion-16-19 2.5t

Look into the oil catch can threads by sm1ke. He installed the catch can to trap any oil droplets, and it's been dry so far. In any case, the cleanliness of the oil doesn't relate much with the carbon build up. It is from oil vapor contacting the hot intake valve. If we don't have the oil vapor, we don't have that problem. Mazda's engineers must have built a very good oil trap inside the engine.
 
I hate beating a dead horse, or any sort of horse, but I will. Been looking deeper into the aspects of turbo-charged gas direct injection engines. Agree with PTguy that the catch cans being empty probably means that Mazda has worked-out many of these issues. Seems that some turbo-GDI suffer from Low-speed pre-ignition (LSPI) and there is certainly an issue with intake valve deposits (PCV oil mist vs. oil vapor well discussed here). The long and short of it appears to be the levels of calcium and magnesium as detergents in oils. Increased calcium as been correlated to increased intake valve deposits so 'SN Plus' oils have been reformulated to have decreased calcium content and increased magnesium. NOACK percentages seem to correlate less than the significance of calcium in the oil. Thus, look for oil with low calcium (Mobil 1 oils are ~1,100 ppm - calcium and ~775 ppm - magnesium). At this point, I'm probably going with Mobil 1 Extended Performance and the OEM Mazda filter. Dead horse beating done. :)
 
Thanks for the info about what is new in the SN+ oils. A quick glance shows that both Castrol Edge and Mobil 1 are SN+. (Mobil 1---sheesh---14 different versions, 6 of which will work in our engines. I'll stick with the version Costco sells. If one wanted a more robust oil, ExxonMobil claims that the 5W-30 Mobil 1 Truck & SUV version is it. Different oils or just different labels with differentiated marketing???)
 
Thanks for the info about what is new in the SN+ oils. A quick glance shows that both Castrol Edge and Mobil 1 are SN+. (Mobil 1---sheesh---14 different versions, 6 of which will work in our engines. I'll stick with the version Costco sells. If one wanted a more robust oil, ExxonMobil claims that the 5W-30 Mobil 1 Truck & SUV version is it. Different oils or just different labels with differentiated marketing???)

One more on the calcium issue in GDI motors: https://www.infineuminsight.com/insight/nov-2016/quenching-low-speed-pre-ignition
There are a ton of choices in the SN+ categories so I think it boils down to low calcium (and low ash chemistry) for our cars.
Oh, and my commute to work is about 2 miles each way; barely enough to get to operating temps, so I'll need to get on it a little more over the longer weekend drives. :)
 
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Look into the oil catch can threads by sm1ke. He installed the catch can to trap any oil droplets, and it's been dry so far. In any case, the cleanliness of the oil doesn't relate much with the carbon build up. It is from oil vapor contacting the hot intake valve. If we don't have the oil vapor, we don't have that problem. Mazda's engineers must have built a very good oil trap inside the engine.

Not sure if the Skyactiv 2.5T has it but the Skyactiv 2.0 NA engine already has it built in to the engine...saw this from a thread in a CX3 forum

I assume they*ve done the same to the 2.5T engine...

https://i.postimg.cc/7ZYKntK0/90-A4-E909-FCB5-47-EE-A0-B9-42-FCAAAABAE5.png

https://i.postimg.cc/nzC8ScTK/AA5200-F0-5-E98-42-A7-B6-ED-6-C65-A46-DD30-C.png
 
Not sure if the Skyactiv 2.5T has it but the Skyactiv 2.0 NA engine already has it built in to the engine...saw this from a thread in a CX3 forum

I assume they*ve done the same to the 2.5T engine...

https://i.postimg.cc/7ZYKntK0/90-A4-E909-FCB5-47-EE-A0-B9-42-FCAAAABAE5.png

https://i.postimg.cc/nzC8ScTK/AA5200-F0-5-E98-42-A7-B6-ED-6-C65-A46-DD30-C.png

This is not catch can system; just an ordinary PCV which all the new cars come with. Some has better separation built in / some don't.
 
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