Engine oil RED LINE or IDEMITSU

Redline recommended 10w-40 Full Synthetic for my 1.8 solid lifter JH turbo application and the tech guy suggested modern synthetics don't cause seal leakage (like OG synths of 25 years ago) and holds up way better than the 40w rating in hot temps and protects much better when cold than even the current crop of Castrol 20/50 dino oil I was running. I swapped over the M81 to the same Redline oil and have not yet noticed any new oil leaks yet.

I don’t use the Mazda-branded version, but Idemitsu is my go-to oil in all of our Mazdas

Idemitsu is the only premix and engine oil I’ll use ... you can order it for a good price from TREx performance out of NJ and he will ship

I use only Redline for all my oils-fluids. For engine oil, I have used 10w40 consistently.

The oil was Idemitsu Synthetic 0W-20 with 12.5k miles on it. Once again, trace metals and flashpoint were within normal range. I also ordered a TBN to measure the amount of additive left and that showed there was still plenty of active additive remaining.

Used to use Motul, now switched to Red Line for the higher zinc content and high heat stability. I rallycross my daily so high RPM and high heat.

In terms of oiling, get a sohn adapter so your apex seals aren't being lubricated with crankcase oil, and instead are injected with rotary-specific oil, like idemitsu.

Redline 5w 40 since break-in, 254k miles later engine still going strong. Plenty of other repairs done, but no internal engine repairs required.

Completed my first oil change at 5k miles with Redline 0w20 and a Mann filter.

Subaru OEM oil is Idemitsu 0W-20. I currently use Idemitsu Zepro\* 0W-20, a high-moly formulation from the same manufacturer.