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I don't think that was mentioned in this thread:

On descent in my C, I push for 500 fpm and trim it hands off. As I come down, MP and EGT both increase, so I pull the throttle back to my former cruise setting and push the mixture forward to about my former cruise EGT. When leveling off, I reduce throttle, then RPM, to match my desired power setting (or airspeed for pattern entry) and lean again.

WOW! I had forgotten about that. Just curious, do you remember what kind of battery pack? Was it a major brand or just something you picked up online or in some store? ADDED NOTE FOR ALL... It goes against traditional logic since you're dealing with a stored power cell. But current best practice is to dump WATER on the battery. Even better if it is in a fireproof bag and you can fill the bag with water.

Good point about CHT. Also on the list of "look for the obvious" first - with new jugs, the fuel injectors were removed from the old jugs and reinstalled on the new. Something as simple as dislodged debris could be reducing fuel to #4 causing it to run lean and hot. And - are you sure that they got the injectors installed on the correct cylinders? Shops do make mistakes...perhaps more nowadays.

Here’s some more simplification from a fellow Air Force guy. Break your “leaning plan” into a few chunks since they have different goals: Takeoff and climb - full rich, full throttle, full rpm. Use airspeed higher than Vy to keep CHT temps in limit, maybe ~115mph climb. As you climb above ~3-5000’msl, you can slowly start to lean using target egt as long as temps are in control, however you can also keep it full rich. Prop stays full rpm, and full throttle. Cruise - you likely just need to use rich of peak or peak as you might have trouble getting lean of peak in a C. You will want to use a key number for 75% power or less (for engine longevity) if youre below about 7000’. Above that, wide open throttle is below 75% anyway. Rpm probably 2500 or 2400, whatever feels smoother. Less rpm equals less power though. Lean to 100 rich of peak is good - do you know how to do this? If you’re sure you’ll be 65% or less, maybe try peak egt which basically coincides with lean to rough and then add a little until it’s smooth. Descending - maybe leave cruise power and enjoy the extra speed. You might need to slowly get richer as you descend until you are in the pattern and then you probably want full rich, full rpm to be ready for a go around.

I agree and do not carry a battery pack any more in a small airplane, especially since this Mooney burned up after a battery pack caught on fire after being dropped. Thank goodness it happened on the ground and not in the air. https://asn.flightsafety.org/wikibase/386971

You specify EGT but did not comment on CHT. CHT values are absolute, where EGT is really about relative values, such as degrees from peak or watching a trend on a given cylinder. There are things about EGT that can lead to variation between cylinders that is not meaningful. Simply where the probes were drilled and inserted will give big variation. In this case, assuming they used the same holes, the tip may not penetrate quite the same distance, tip is bent a little, or the flow from this new cylinder is slightly biased in one direction versus the previous one as it flows during exhaust valve opening.

Don's modification was most likely just entering the header parameters for his engine. A search on the file name pointed me to egtrends.com, a site that no longer works. As I recall, I looked there when I originally downloaded the file about 9 years ago (the version I posted in this thread is in the the file section on Mooneyspace, I think), and was able to get into the thermo formulas used to build the spreadsheet. I was satisfied with their veracity at that point, although I can't remember if there were any coefficients used to adjust the theoretical to the empirical. Might have been, based on the accuracy of the output.

I can see @hazek's safety concern. It would be a pretty different situation in a Mooney vs being a Pax in a commercial airliner. You can't exactly jump up out of your seat and stand in the isle as you get the fireproof bag. And granted, the major manufacturers (UL Approved) batteries are much less likely to have a catastrophic runaway issues. But it still can happen. I have a battery pack, but then I try to charge it, my flashlights, etc., to 80ish percent. I don't have a real way of knowing, but my battery pack does have lights to show how charged it is, so I stop at 4 out of the 5 lights. That last 20% is the hardest on the current type of batteries.

Unlike the Rocket, there is no legal amount of lead or batteries in the tail that will fix those numbers.

Love those numbers! Were they 520s like Erik?

FWIW the data comports with things posted on BeechTalk several years ago by Walter Atkinson. Just curious about original source. Last Modified by Don Kaye, but no way to tell what the modification was.

I know of 2 local to me that went 3,200. They were topped in that time and had turbo overhauls about every 1,000. Operator thought he'd pushed the envelope on the bottom ends far enough.

There are notes throughout the spreadsheet that discuss his methodology, I think. I don’t have Excel on my Mac and I lose some of the formulas and notes when Apple Numbers imports the file. I’ve been referencing it for years and the empirical engine data I’ve collected validates the spreadsheet data to an acceptable degree of accuracy. Something less than about 3% deviation.

Any idea where Michael Mahoney got the data?

LOPFFvsHP.xls

Where did that table come from?

I don't but my point was that I am already exposed to this risk and would rather not add another battery and with it even more of this risk. Thank you for the recommendation, but I would rather use the cigarette lighter socket if at all possible.

It’s approved by the FAA for commercial flights. Are you currently carrying a fireproof battery bag in your airplane? To each their own I suppose…It never occurred to me that someone who would consider charging their phone/tablet with a plug-in cigarette lighter charger might find a high end power bank with a sophisticated battery management system to be the more risky option. I didn’t come up with this set up on my own. I have several colleagues who also fly regularly for work. This has become the go to set up for powering StarLink in flight as well as other devices. I’m likely going to buy a second because I occasionally fly into locations that don’t have an FBO and therefore don’t have power or Wi-Fi readily available. My flight bag is completely self-contained power and broadband solution. If I add a second power bank, I’ll I have roughly enough power for full day worth of work and internet usage, plus excess to keep handheld devices topped up. High capacity, smart power banks and StarLink have been a game changer.

Although you were pointed in many good directions, I would argue the number one things to learn and understand before doing anything is this graph: This graph explains big picture how you can operate your engine, that is the available combustion envelope within which you can operate your engine. After you understand the graph above deeply, then you need to learn how adjusting any of your controls will move you around on the above graph. Then finally you can go look at the sources people linked to understand in which positions of the graph above you should want to operate in. It's all very simple once you understand the above graph.

13.7 works for a compression ratio of 7.5. The multiplier varies with compression ratio. For instance the multiplier for my TIO-540 with a compression ratio of 8.0 is 14.3. EDIT: The Lycoming O-360-A1D in the OP's M20C has a compression ratio of 8.5 and a LOP fuel flow multiplier of 14.9. @oisiaa

Did you put new spark plugs in at the same time? A plug not firing perfectly will cause a higher egt.

That Austro 330 weighs over 400 lbs dry excluding radiator and intercooler. And you need a heavier engine mount and a huge bulbous cowling. I bet it weighs 250 lbs more on the nose than your M20E Lycoming and has less power at sea level. And the huge cowling might cost 5 knots in drag. Now that EcoDiesel you reference weighs over 500 lbs dry without radiator, intercooler or oil cooler. Packaged and cowled I bet it is close to 600 lbs on the nose -about 350 lbs more than your M20E Lycoming with about the same power. A real “lead sled” Aviation is a balancing act of compromise. And details matter.

Those apples have engines rated in thousands of horsepower. Our oranges have engines rated in hundreds. Commensurate order of magnitude reduction in intake size might be comparable, like what is used on the Rotax applications. Thanks for the pics though

Thanks all!