There was a big law suite over this a while back. It started because Redline is the only syn. oil thats compatable with the rotary engine. They started stating that and the other companies didn't like the fact that Mazda was saying only to use that specific oil. So they sued them and since then Mazda said forget it and said only to use conventional oils. This leads back in the days of ISMA, for those that remember.
Red Line oil contains high amounts of sillicon, when it is injected and burned in the engine. It doesn't leave a stiky residue like other synthetics do, it burns much much cleaner.
Originally posted by BLK98.5SVT:
Hmmmm, I was just talking to a friend at lunch who just drove an RX-7 R2 up from Florida. He just bought it from a guy who has some other sweet cars (Supra TT, Skyline) but I digress. The guy told him NOT to run synthetic. In fact, it also states in the manual specifically not to use it. Something to do with how a rotary engine runs.
