Davis Aviation 550 Engine Conversion
Exclusive Alaska distributor for the Davis Aviation (formerly Bonaire) 550 engine conversion.
If the idea of 20% shorter takeoff and 8-10 knots increase in cruise speed at similar settings intrigues you, then consider the 550 conversion strongly, whether you're about to change engines or not. The fuel burn penalty is minor but cannot be considered a penalty at all when you factor in the speed, not to mention extra available takeoff power and the fact that you can throttle it back if you like.
The following quote is from an article titled Colemill Foxstar Baron: A Better Baron? by Peter A. Bedell, AOPA magazine Sept 2000:
"The IO-520 is a good engine, but it was not built under the minimum-horsepower concept like the newer IO-550. Under this rule, the IO-550 must produce at least 300 hp plus 10 percent and minus zero percent. The 520 can be within plus or minus 10 percent of 285 hp. That means that with all of its accessories dragging it down, an IO-550 will deliver the full 300 hp (and probably more) for a net horsepower increase better than the 30 hp total listed on the specifications sheet. Not surprisingly, owners who've made the conversion see cruise speeds of their airplanes increase by 10 knots or so. In addition there are proportional gains in takeoff and climb performance."