I need some advice, i need to know which oil is best for my australian series 4 rx-7 with a series 5 engine.

Castrol GTX 20W/50

All the top oils are going to be great for your motor. Even the new synths. But, there will be those that say to shy away from synth unless you remove the oil metering pump and pre-mix 2 stroke.

If breaking in engine a good mineral oil Castrol etc...after break in Royal Purple or Red Line.

Idemitsu is good rotary oil also.



You will always get different answers, it's all about opinions.



You couldn't go wrong with any oils mentioned. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

I just picked mine up and the former owner is a rotor head as well and we both use synthetic. THe theory is that mazda is just covering their ass if you use cheap ass syn. oil cause when it is in the combustion chamber it may leave behinde a residue. So if you use syn. use the good ****. THe former owner used mobil 1 20w50 and i use Castrol VR1 "racing" oil 20w50 cause i get it so cheap why not.

20w-50???? do you guys run that in a turbo car or an N/A. I would think it would be over kill for an N/A.

Yes in the turbo fc's.



Not sure if any n/a guys run 20w/50.

I used to be running 10w-40 in the '86 GXL when I had it...then I switched to 20w-50 and it was quieter, seemed to respond better and didn't burn nearly as much oil.



10w-40 is good for an N/A if you're in a climate where it's almost ALWAYS cold. 20w-50 is generally a good oil though.

I use 10w 30 in my N/A fully synthetic royal purple. She is quite but i live in PA where The weather can be cold in the winter but the summer we heat up nicely. It does burn about a quart every 900 to 1200 miles but i like the way she runs.