I have "one of those engines" 10:1 , and electronic ignition on one side.  370 HP is claimed at 2800 rpm, though I don't personally run that high. 

I could not be happier with my engine.  Compared to the factory Legacy, which I have 6.6 hours of HPAT training in, my bird has a serious overall performance advantage, and burns less fuel.

Recently I took a neighbor with me on a flight, to test climb ability; our TO weight was 2356 lbs.,  at 21,000 feet we were still climbing at 120 KIAS, 500 fpm!  Don't think a stock IO-550N could do that.

It would be interesting to know what a stock IO-550N would dyno. 

Micah Froese
Lancair Legacy
85 hours



Douglas Brunner wrote:

Now for another controversial topic - engines...

I just watched my engine get dyno tested.  It is a normally aspirated IO-550N EXP with 10:1
compression and magnetos.  It made 325 hp at 2700 RPM.

There is an engine builder in California that claims 370 hp.  I have a question for those who have this engine:

   - Are you sure you are getting 370 hp?
   - Have you seen the dyno test?
   - Do the recent Reno race results support the claim?