I know you guys have already answered this question a million times....I've been doing a little research online and it's kinda tip for tap....Reason for me asking is I'm about to put the 2nd engine in this car and want to start off right this time....Also synthetic or non?...Thanks Again for you time. 
Well.....like you said Mazda recommends 5w-20...On my factory engine I did that, but I was forever adding oil...yes, yes, I know that rx-8's are also designed to burn oil but not as much as I was adding. on the 2nd engine I was using 5w-30 synthetic because that was what a Mazda dealer told me to put in it....Im looking forward my 3rd engine and don't want to mess this one up. I need an rx-8 owner to give me some pointers. Thanks
Thanks... I would keep that in mind. Its starting to get on the warm side here in NC. so when I get her back I will defiantly go with 10w-40. Just what I wanted to know!...THANKS AGAIN!
Well.....like you said Mazda recommends 5w-20...On my factory engine I did that, but I was forever adding oil...yes, yes, I know that rx-8's are also designed to burn oil but not as much as I was adding. on the 2nd engine I was using 5w-30 synthetic because that was what a Mazda dealer told me to put in it....Im looking forward my 3rd engine and don't want to mess this one up. I need an rx-8 owner to give me some pointers. Thanks
Thanks... I would keep that in mind. Its starting to get on the warm side here in NC. so when I get her back I will defiantly go with 10w-40. Just what I wanted to know!...THANKS AGAIN!