My thoughts are first, the oil filter is tiny. My Goldwing motorcycle has a bigger filter. Denso is the oem for mazda and Toyota. I’m always going to use a Mazda filter. Why? Because it’s guaranteed to have the flow potential that my skyactive turbo engine requires. I do my own oil changes, I discovered the dealer had installed the value line filter when I bought the car. If you have the dealership doing your oil changes, you are probably getting the value line filter, it will have a MV at the end of the part number on your invoice. To me, the regular factory installed filter is usually just a few bucks more, even cheaper on line. It’s a $40,000 car. I see a few comments about the oil change interval, pointing out how modern synthetic oil will last through the long OE recommend interval. The reason to change the oil more often, in my case every 3,500 miles, is not because the oil doesn’t have the potential to go 7,000 miles. It does.
The reason I recommend more frequent oil changes to my customers with mazda skyactive engines is the incredible compression ratio those clever engines can achieve. In the NA, up to 14.5 to 1, 13.5 in the US, and 10.5 in the turbo. With those values, (used to be found in racing engines only) the engine is going to experience some significant blow by and windage. If you have seen one idle with the oil cap loose for a moment, that cap will dance from the windage. What that means to the oil is fuel contamination. Sure, you can have your oil analyzed, or just take a whiff off the dipstick.
By about 3,500 miles I can smell fuel. I use what I believe is a very good quality oil, pennzoil ultra. Great as it is, fuel will break it down.
It’s just my opinion, but that’s the reason I don’t go 5,000 or 7,000 miles oil change intervals. I’ve taken a look at filters, like wix xp. It would probably filter better than the denso made OE, but Im not sure about flow specs and every aftermarket filter for our application has a adbv, the OE doesn’t. Mazda sure keeps it’s specs on bypass range hidden, I can’t find a spec on that either.
The reason I recommend more frequent oil changes to my customers with mazda skyactive engines is the incredible compression ratio those clever engines can achieve. In the NA, up to 14.5 to 1, 13.5 in the US, and 10.5 in the turbo. With those values, (used to be found in racing engines only) the engine is going to experience some significant blow by and windage. If you have seen one idle with the oil cap loose for a moment, that cap will dance from the windage. What that means to the oil is fuel contamination. Sure, you can have your oil analyzed, or just take a whiff off the dipstick.
By about 3,500 miles I can smell fuel. I use what I believe is a very good quality oil, pennzoil ultra. Great as it is, fuel will break it down.It’s just my opinion, but that’s the reason I don’t go 5,000 or 7,000 miles oil change intervals. I’ve taken a look at filters, like wix xp. It would probably filter better than the denso made OE, but Im not sure about flow specs and every aftermarket filter for our application has a adbv, the OE doesn’t. Mazda sure keeps it’s specs on bypass range hidden, I can’t find a spec on that either.
I will edit when I find a better analogy. 
Hopefully shorter oci (3K next) will never get me there.
