So in was on a web site that says royal purple synthetic is good for rotary engines and it gives a hp gain. Mazda says not to use synthetics because they gum up the inside of the rotor housing and causes carbon deposits. Who do I believe? Does anyone have any experience with the synthetic topic? I looked through the FAQ but couldn't find anything on the topic.

 

You can run synthetic oil if you want.

Most of the information about running synthetic in a rotary being a bad idea is 20+ years out of date.

This has been covered many times before. A quick search in this forum for "synthetic oil" will turn up a lot of info.

 

if your skeptical in what oil to run they also offer idemitsu oil made especially for the rotary engine..

:AA:

 

Idemitsu sells at a serious premium though. In my opinion it is largely unnecessary when all off the shelf oils are suitable.