What Kind of Oil?
 

I need to know what type of oil i should use for the best performance. I have an 86 na, in near perfect shape (engine that is) with 104000 miles. I see that mazda recomends almost every wieght which should I go with?

Do a search there's a million oil threads or should I say debates on here. If you wanna go by the book use non-syn 10w30. Most choose to run 20w50 Castrol GTX. Some, including myself venture into synthetic. There are a bundle of opinions on which syns are of high enough quality to be considered a match for the rotary. Racing Beat recommends Royal Purple if that's of any interest to you. AMS Oil, Redline, Mobil1 seem to be popular synthetics.

Yes, but you need to look at the temperature range to determine the proper weight.

Castrol GTX (not Syntec) has had very good results in rotary engines over the years. Synthetic engine oil isn't worth the money unless you are racing on the track.

I think you need to read the book again. ;)
http://www.fc3s.org/how_tos/manuals/...ION_SYSTEM.pdf

Thats what im currently using in my TII

Good point, Icemark, I forgot that some people don't have Adobe Acrobat and/or do not have the high-speed internet capabilities to pull up that file in a timely manner. Here is a better picture that shows the grades for a given temperature. BTW, the newer lower-priced "synthetic" oils using Group III base stock may or may not be considered "mineral oil" as per the 1980's Mazda definition. Regardless, I do not consider them to be worth the extra money.

Thanks everyone who replied I tried Castrol GTX 20-w50 my engine seems to idle smoother already could be that i had cheap thin oil in it before but we'll see how this oil works out thanks again

?? Seems to me that 10w30 spans the normal temperatures that we'd encounter as North Americans. That's what it comes with from the factory, so where exactly am I wrong here?

10W30 should not be used above 80-85F.

my summers and springs in Northern CA often see's 90F or above.

And some place like the South, or Texas/Arizona/New Mexico/ Southern CA or even New York city, often see temps above 90F.

So... you need to use the proper oil for the proper season.

Its far more common in North America to use 20W50, because sub 20F temps are more rare. And since 20W50 is stable from 20F and above...