...and if your mission is to get more out of your engine without sacrificing reliability then the way you operate your engine is critical.
First, with higher compression pistons, you do NOT want to fool around with LOP.
Lycon recommends 125 ROP.
Second, you do not want to run the engine real hard at lower altitudes. Not only will you burn a lot of expensive gas, but you'll be in the yellow arc on your airframe.
Third, you need a prop that will make use of the additonal power. A CS will be very useful.
4th, you want to limit the max RPM. I have my prop governor set to a little less than 2,700
5th Fuel injection is needed.
OK..so what do you get for your money...and I'll agree it isn't cheap for a Ly-Con engine:
The ability to climb fast to altitude (it burns about 14 gph during climb) and then settle down and cruise at a reasonable fuel burn.
Once at altitude, you can throttle back and lean and get a reasonable fuel flow. E.G., in comparison to a friend in a 0-360 CS RV-6 I can fly at his best cruise speed on less fuel. Since his engine runs hot on climb, he is limited to a shallow climb angle. He's tried all the tricks in the book to get his CHT's down and the engine just runs HOT. When I went from a regular IO-320 to a Ly-Con IO-320 I expected it to run hot. In fact it did not. It runs as cool as the regular compression engine. CHT's are never over 300. Oil temps are just in the green during the winter and in the middle in the summer...and that is with half the oil cooler blocked off. I'll admit, I was very surprised at this.
At 8,500 foot altitude I run it at 2400 and 22 inches and 125 ROP and fuel flows are about 9 gph and 195mph still air cruise. If you want to get better fuel flow, you can either slow down or go higher. I've tried slowing down, but 160 feels too slow, even though fuel flow was a shade over 5 gph. Ok...you got me...I did lean it a bit thinking that with the throttle that far out, I couldn't hurt it, but I still stayed ROP.
Since I can cruise climb at 160- 170 with rpm less than 2600 and all temps in a comfortable region, I frankly can't see how I am over stressing this engine. It currently has about 200 hours on it, uses no oil to speak of, purrs....well..you know...I gotta believe it will last a good long time. Kenny at Lycon said it would make it to Lycoming recommended TBO.
I'm not sure what the definition of a grenade engine is, but if it is what I have on my plane, I'd say it's pretty trick.
Tom Hunter