Talked to a couple of folks involved in the long, frustrating attempt to get the piston Evo ready. SMH.
The CHT redline is 500F, exceed it by 1 deg and it's overhaul time. The engine software doesn't take measures to reduce CHT until it hits 496F, it will let it run at 495F continuously. I believe the metallurgy of the cylinders is the same as on any other IO-540.
The TIT redline is 1750F, the software will let it run there continuously.
The ie2 engine is sensitive to temperature, or maybe it's DA. At a 3,000' field elevation, going from 85 to 95F cuts the ROC in half. Don't know why, maybe it's retarding the timing to increase the detonation margin (max MP is 46" vs. 42" for the Mirage engine with the same 350 hp.) but the result is dramatic. In one test, a climb to 9,500' took 30 minutes. That's at 140 KIAS so imagine the climb gradient. And both the buyers of piston Evos are in Texas.
The empty weight is over 2900 lbs. with only a partial interior, that's 2-400 lbs. heavier than a turbine.
It's hard to imagine a mission for this that couldn't be done better with a PT6 and an aux tank. With a used PT6 it could even be cheaper, and far more trustworthy.

what in the margin of error for the CHT probe, surely it's +/- 2 or 3 degrees, not in the tenths of a degree

Sounds like a real POS. Sounds just like the FADEC I had on my experimental, except mine always had great performance, it just didn't give a crap about CHTs, and always probably ran it in the redbox.

I never liked it that Lancair was going for that new fancy, expensive FADEC engine. Should have put a TNIO-550 or, at least, whatever Cirrus uses. This way you know it works.

The EVO with a TSIO-550 would be an interesting plane, especially if the empty weight is 2200-2300lbs, that's about what my ES weighs empty

I don't think that's doable, the lightest finished Evo I know of is 2555 lbs. and that's with a turbine engine. Any reasonable piston engine choice would certainly be heavier.

It's dead, Jim. At the Evo owner's meeting this weekend we heard that the two piston Evolutions are being converted to turbines. We also learned that the suit by one of the purchasers of a piston Evo against Evolution Aircraft Co. is still ongoing.

Not surprised but sad to hear. It seemed a promising option for a long range aircraft. I had looked at the piston Evo on display at Oshkosh a few years ago but got bad vibes about it so passed,

I'm not sure I'd see or enjoy the benefit the piston variant over a smaller PT6 considering the -21 engine. The cabin is pressurized too well to cruise in the mid 20s and you want to get to the high 20s/low 30s quickly. Really... the plane needs a -135 or more.

Dave's Evolution is doing 34 (!) gph at FL280 doing 290+ knots. RVSM altitudes will open up opportunity for less fuel burn and more weather/tailwind options. Discipline to pull back can get really close to matching fuel costs with a piston engine and will give more options for hot/high. You may not be able to fly 25 hours on one tank, but 6+ in a PT6 seems like a great option to me.

The LX7 has a piston version with a Continental 550 that looks pretty speedy and fuel efficient, especially since you can run it LOP. If you're looking for something with a piston, that would be the one to look at. I think RDD has done a good job modifying the IVP airframe ... so if you're really jonesing to fly 2000 nm nonstop in a piston, that would be the plane to check out. Very attractive aircraft - saw the PT6 version at OSH in 2019 and liked it a lot.

5+ hours in my M600 is about my personal limit, and my pax won't stand for anywhere near that long!

Real shame about how the whole Evo thing turned out however ... glad Dave is flying his.

I thought so too at first but the longer I looked at it the less sense it made. The lighter weight of the turbine enables adding a big enough extra fuel tank to give it as much range as the piston while flying faster. Cheaper fuel and lots of used PT6s available reduce the cost delta versus the new, premium priced piston engine. And if you really are flying eight or more hours with nowhere to land and refuel on the way, that's the last place you'd choose a new, unproven engine over one of the most reliable engines ever made.

At Oshkosh I talked to the owners of the first (and only remaining) piston Evolution and the test pilot who did the majority of development flying on it. The story is that once they got the bugs worked out the first piston Evo worked well, and the owners are happy with it, but it is slower than expected. The owners say they cruise at 215 kts, top speed might be 220-230, less than the 240-250 the factory was advertising. The factory designed a lower-drag cowling, trying to hit the advertised speed, which was used on the 2nd and 3rd airplanes, but inadequate cooling caused problems. Both of those airframes have since been converted to PT6, the only piston Evo left is the first one.

I personally don't think that expensive, fancy new piston engine ever made sense, even on day one.

I was so in love with the Evolution, and they broke my heart.

That does not sound like something so would own. One correction, I thought the Lycoming was 375hp? Seems
Like the same issues on the Cape Air planes. It would be easy to fix with different algorithms. In the meantime one could strap a TN550 in there. May require some mods, but that is what experimental is for.

My dream for the Evo was to put a -61 or -52 on one. Won't get the chance now that I sold mine.

Nope. The 375 hp model Tecnam uses came later, the piston Evo was only available with the original 350 hp ie2, as seen in this company ad calling it an "EVOP-350":
http://www.evolutionaircraft.com/certif ... -for-sale/