I just looked it up in Taylor. Still looking for the definitive chart.
30:1 is definitely down on power.

One more thought -- the way ratings are set for over the road truck engines is rather unique. An 11 liter engine, for example, may have a rating of 650hp for marine use, where power density is key, and emissions are not as tightly regulated (unregulated until recently). The same 11 liter engine may be available for class eight (over the road) trucks at ratings of from 280 through 370hp. The only difference is the calibration in the ECU and the price! Fleet owners may buy the 280 because it will use less fuel over its life. It may last longer and cost less to maintain. The owner operator will choose the 370hp because it is easier to drive, and will get him home faster. He'll pay a premium for that extra power, and the engine company may pay more for warranty claims.

But since the same basic engine is producing from 280 to 650 hp (with a difference in speed of only maybe 25%), obviously the 280hp truck engine is set to run a lot leaner (more excess air) than the marine engine. This gives better fuel economy, and such an engine may be running at my guesstimated 30:1 AF ratio at rated power.

Jon Lauter

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org