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Superior 0-360

rv9aviator

Well Known Member
I received information from Superior Air Parts on using an o-360 instead of an 0-320 in my RV-9A. They said the 360 weighed virtually the same as an 0-320. They also said to simply limit the manifold pressure to 26 in. which would produce 160 HP if I was concerned about too much HP. Does this sound right? I thought there was about 50 lbs difference between an 0320 and 0360 engine. I would love to have the extra HP for High altitude flying but don't want to screw the slow flight handling because of a heavier engine.
Thanks
Jim Wright 90919 Wings Arkansas
 
From the different figures I've seen, weight difference is 9 - 14 lbs. The only other disadvantage is that it will use a little more fuel if you de-rate it using the throttle. Sucking against the throttle reduces the efficiency of an engine. Some people reckon you may get fatigue cracking if you run an O-360 in a 9A at full throttle too often because of the thinner skins.

Regards,
Conor
#90990 wings
 
I need to check on the insurance issues using a larger engine too. I bet that will be a show stopper.

Jim 90919 Wings Arkansas
 
I spoke to the folks at Falcon Insurance and they said go for it. The Superior De-rated 0-360 was fine with them. :D
Jim 90919 RV-9A wings Arkansas
 
Derated O-360

Or, get it derated by Superior when they build it up. Have them put the low compression pistons in it. Lycoming rates the O-360 w/ low compression pistons at 168 hp. That would also let you burn regular unleaded auto gas instead of premium unleaded auto gas if you were so inclined.

Jim
 
O-320 vs O360

I'm curious, why would you want to go the extra mile for a larger engine, then have to derate it back to the original suggested engine?
 
That is the wierd part. The only thing that de-rates the HP is a red mark on the Manifold pressure gage. ;)
Jim
 
Ron said:
I'm curious, why would you want to go the extra mile for a larger engine, then have to derate it back to the original suggested engine?

Ron
I think the major reason is more HP higher up. 140+- v 114 at 7500ft without the engine power pulse messing with your tail skins.

It not much larger (1 or 2 inches wider) and with the new composite sump it is about the same weight.:rolleyes:
 
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