Mooney turbo question


#1

Hey Fellow turbo pilots! I have a Mooney 252 which is turbo charged. The POH says to lean it to peak TIT. Of course I have an engine monitor and lean find etc. Does anyone use one of those and add 50-100 deg rich to where the JPI peaks. My TIT is usually around 1450-1500 while using the JPI and nowhere near the peak TIT max of 1650deg like the POH says to use. Thoughts? Any other 252 pilots? Do your TAS’s match the POH numbers? Anybody have much experience with ice in a mooney? My tail number is N944Y for those that like to ‘watch’ other planes. :slight_smile:


#2

You have 1 flight showing! LOL :laughing: :laughing: :laughing: Your panel makes up for it! 8)


#3

Sounds like a new owner question, congratulations.

I can’t specifically answer your question since I fly an airplane where the mixture takes care of itself. Having said that 100 rich sounds like to much and your TIT is reflecting it.
The other thought is, are the engine monitor, harnesses, JPI etc. all calibrated? On a 14 year old airplane it wouldn’t be out of the question that one of them is off.
I do know that engine temperatures, especially in a turbo charged, closely cowled airplane are critical. For sure keep checking. There must be a Mooney owners website somewhere on the interweb.

Ice in a Mooney, no idea since I tend not to drink while I’m flying. :laughing:

John in Saudi


#4

Or a 24 year old plane either :stuck_out_tongue:


#5

Hey, I did all my math classes in the Lucia Mar Unified School district. Don’t blame me if I can’t ad.


#6

Or spell… :laughing:


#7

busted. actually that one was on porpoise.


#8

I would run 50-75 rich of peak if your pulling power and trying go fast. If you don’t mind running at less than 75% (more like 60-65%) then go lean of peak by 75. Don’t worry about the POH book numbers for temp. The temps your getting are about right based on what you’ve advertised as operating technique.


#9

Have you ever thought about GAMI Injectors?


#10

I have an '86 252 that I’ve been flying for about 500 hours with a little time in other turbo Mooneys. I also have a friend that has owned three different turbo Mooneys over the last 20 years who has helped me establish an operations manual for engine management. In addition, I consult my Mooney Service Center regularly and take part in the MAPA Pilot Proficiency Program. I run the airplane at 75% all the time using a key number of 53. In my case that’s 28 in and 2500 RPM. The airplane is happiest there. Yours maybe different, but a key number of 53 will yield 75%.

I have a JPI but do not use the lean find. Instead I find the hottest EGT cylinder (always #3) and lean to about 1450. At that temp. fuel flow is a little rich compared to book, just over 14 gph. Cylinder head temps are below 380 F unless it’s summer and I’m in or near the flight levels. Then I just crack the cowl flap. It doesn’t take much to get the hottest cylinder (usually #5) back under 380 and you lose maybe a knot or two. TIT will usually run under 1550.

I run the engine very conservatively. My mantra is a cool engine is a happy engine. My interpretation of the POH recommended fuel flows were more marketing (best range) and less focused on long term engine durability.

As for TAS, I usually get about 178-180 knots at 10k, low 190s at 17k. I don’t remember what book says and don’t really care.

As for ice, I do not have TKS so any ice encounters are brief and accidental. I have had trace amounts of ice with no noticeable handling changes. My friend with an Acclaim has picked up at least a half an inch in a climb with no noticeable handling changes. I have seen pictures of more ice on Mooneys. However, lots of ice on a clean laminar flow wing does not interest me.

I think if you asked 10 pilots the best way to run an engine, you will get 11 answers. GAMIs also do help level the fuel flow to the cylinders. However, the -MB engine already has a pretty good balanced fuel injection system unlike the -LB or -GB versions.

Hope this helps. You can probably guess what my tail number is. I do fly fairly regularly. Oh, you should also join MAPA. The people there are very nice and a huge resource.


#11

I like the book “Fly the Engine” by Kas Thomas, founder of “Light Plane Maintenance” magazine, both a must read for every pilot. He makes a lot of sense and gives great analysis of how to operate various turbo and normally asp engines, and takes the time to explain the “why”.


#12

I would run the TIT no higher than 1550. 50 rich of peak will have you buying cylinders before your TBO on the Continentals. Since you already have JPI the best thing you could do is get GAMIjectors and learn how to run lean of peak properly and safely. Otherwise just run the thing a little sweet (1550 instead of 1650) and rock and roll. The 252 is a blast to fly.


#13

Thanks to all those that replied and gave me some advice. If anyone wants to keep comparing notes and adventures on mooneys or other birds thatd be cool.


#14

It can never hurt to run it at the lower temps you’ve been running it at. Replacing a turbo, your life or other parts of the aircraft are much more expensive then the few gallons of fuel you’d save over a few years time.
Remember it’s a metal moving part. Less heat, less wear and tear.


#15

Well said… !


#16

One other important thing to consider that I am surprised was not already addressed here is the fact that “peak TIT” is not a hard and fast or absolutely-always-the-exact-same number. “Peak TIT” will vary along with your flight parameters - altitude and temperature (i.e. atmospheric density) and manifold pressure and rpm (i.e. engine power) for examples. That’s why we are taught to find the relative “peak” as opposed to “1650 deg” in your case - and also do not confuse “peak TIT” with the redline limit certified by the engine manufacturer. They were never meant to be the same thing!