Mazmart only sells the S2 oil filter but says it can be used to replace the S1 filter. They say it is a superior filter. Any thoughts?

 

IIRC the return valve is different than the S1 filters. I was given half a dozen of these S2 JDM Mazda filters. Work great with my 06 RX8. I don't see any difference other than the S2 filters are bigger. Still fits fine.

 

Thanks. In my search I did find the bypass valve opened at a different pressure, but it doesn't seem to be a problem unless the filter is clogged. Changing oil at 3k miles shouldn't ever create that problem.

 

That's right. . Keep to a reasonable OCI and you should be OK. Nothing like fresh oil on performance engines to keep everything tickety-boo.