Originally Posted by mc_chofo
i'm looking for the perfect engine to run at a track which is above 6500ft above sea, and some people is telling me that the sirio will outperform any novabased engine at that hight
any opinion will be appreciated
What ever performance you get with any engine at sea level, you will get at that altitude, if properly tuned and adjusted for high altitude operation.
In other words if the Sirio or Novarossi outperform each other at sea level, it will do the same up there.
The question is how well can you set any of them for operation at 2,000 meters. All engines loose apx. 10% power every 1,000 mts. so you must try and recover lost power by increasing compresion ratio or nitro %, or a combination of both, you must reduce carb venturi size to compensate for less air, and you must experiment with smaller volume pipes.