Hey all,
New to the group, so please indulge me if this seems like a dumb question....
I've been interested in getting more performance (> 500' per minute) out of my O-200. I know there is an STC for the Lyc O-235, but what about juicing up the Continental motor??

I believe the standard compression pistons are 7:1. Surely they could be stepped up to 8.5 or 9:1 with little concern for increaed TBO and/or excessive wear on the bottom end. Has this been considered / explored

Welcome aboard, Ron!

Yes, it has been done. There was a one off STC for the O-235 re-engine, but it was never offered to the public, to my knowledge. There is no market for it, as the cost for the minimum HP gained is prohibitive. It probably made sense to someone who had a spare O-235, and an engineless 150.

Yes, there is a class of experimental racers that use modified, suped-up, O-200's. They're high on performance, but low on durability, just like NASCAR. They run custom mixed racing fuel to handle the higher compressions, and custom propellors to handle the power and deliver the speed. Pistons are one-off forgings, machined to fit, and cylinder heads, crankcase, camshaft, crankshaft, induction, and exhaust have all been modified, just to name a few. To do this, you would have to register your 150 as experimental, with the only advantage being the ability to spend extremely large sums of money just to devalue your airplane. The only thing in this category that makes sense (for some) is a 150hp Lycoming O-320 or 180hp O-360 STC'd conversion. There are several owners of "150/150's" and I think "180/150's" in the club.

Little concern for TBO? NASCAR takes a basic 180,000 mile engine and turns it into a rip snortin', asphalt rippin' 500 mile engine. Lets see, similar performance in an O-200? 5 hour TBO! If you're lucky!

Carl

As a general rule, if you want a faster airplane sell your slow one and buy a faster one. Speed mods cost a fortune and produce minor gains.

There is a very good article on 150/150 conversions and they note in that article that, "The total for a 150/150 conversion with aux fuel tanks will run in the $45,000 to $50,000 range."

Thats 45k after the intial price of purchasing an airplane. Which most likely cost you 15k for an older timed out plane.

So 60k for a faster 150. . . Ask yourself, what kind of high performance plane could I buy for $60k? Mooney, Bananza, Piper Arrow, c182 are some that come to mind.

this is something I have been interested in since the day I moved to a small grass strip with trees on both ends.I don't think a 150hp convertion is the way to go all you need is about 25hp to make the 150c climb out with two people and full fuel and not feel like you need to lift your feet to clear the trees. It seem there is not a lot out there if you have a lycoming there is lots of good suff people like lycon are doing.
It seem to me if you could bump the compression clean up the ports biuld a better exhaust and slightly larger carb you should be able to get 25hp with out sacrificing reliablity
But I don't think your going to find to many people on this site talking about stuff like this.
feel free to Email me if you come up with anything.

there are higher compression piston avalible at light speed engineering any compresion you want for $970.00 a set
they claim 15 to 20 hp gain with 9.4to1 this might be a little to high 8.5-1 would be better

There are all kinds of "experimental" things available.
Not much in the way of "street legal", unfortunately.

The performance you are looking for is available for a fairly inexpensive price, its called Vortex Generators, special wing tips, flap and aileron gap seals, a Sensenich prop, and 28 degree timing.

Charles

I think you fail to understand the O-200 is the tail end of a long, and logical growth of what began at 65 horsepower. The displacement has been increased, the camshaft altered, the redline RPM increased, the size of the carb increased and so forth. The engine has all but reached the end of the line of performance improvements without a sacrifice in reliability. The bottom end of the engine can handle little more (the O-240 is all but a O-200 bottom end, but the engine was, from what I understand, not real reliable, the new one, I'm sure, benifiting from new technology and other internal improvements.)

More performance for the 150 is best gained by adding airframe mods such as flap and aileron gap seals, vortex generators (probably the best improvement), and performance wing tips, to name a few items.

Charles