IO550 vs IO540

Rbnew · Post by **Rbnew** » Wed Feb 13, 2013 9:34 am

Does anyone know, how Continental can get 310 hp out of their IO-550 while Lycoming can only get 260 hp out of IO-540?

Post by **Spike** » Wed Feb 13, 2013 10:01 am

Lycomming can get 300HP out of a 540 and does so regularly. There are a whole fleet of aircraft that use 300HP lycoming 540's. Now, what you are noticing, is that some of the 540 line is derated for aircraft like 182's, TB20's, AC11, and the RB10. This is generally done via an RPM / manifold pressure reduction I believe.

This helps longevity and the maintaining of targeted power at altitude.

John

captain_john · Post by **captain_john** » Wed Feb 13, 2013 3:17 pm

Spike is pretty darned close, but let me add some details.

The 300 hp 540 I fly behind in the Cherokee Six is an Angle Valve 540. That is how they eek out the extra 40 ponies

It is kinda like the difference between the parallel valve 360 cranking out 180 hp and the angle valve 360 at 200 hp.

The angle valve engines weigh more but breathe better, hence more power.

Does this help?

CJ

Rbnew · Post by **Rbnew** » Wed Feb 13, 2013 8:29 pm

Yes... I see there are differences. Thanks for the explanation.

captain_john · Post by **captain_john** » Thu Feb 14, 2013 8:46 pm

Soooo, ya thinking RV-10?

CJ