I have used the water/steam clean method on all my Rx7's. I haven't yet done it on an Rx8/Renesis. Nothing to do with the engine, more of where to let the water get sucked in from (vacuum lines) that will evenly get to both rotors.

do NOT do this if you have a stock cat. pretty damn good change you will burn it up...


For those that do not know about this. Get about 2 gallons of clean or distilled water. Drop a vacuum line that will lead directly into each rotor combustion chamber and keep your foot on the throttle just enough to keep the car alive while drawing the water into the engine. probably around 3-4k RPM's.

 

Best way to clean the carbon is to take it to the track and do some laps. This will superheat the engine and burn off the carbon.

The next option is to water decarb.. Use the service port in the LIM. Use one nipple at a time and hover around 4000 rpm to keep the engine running. Also, keep a watch on the engine temps.