Need numbers to run an M20K 231

[jetpilot12]

I sold my M20C and I'm now buying an M20K 231 with an intercooler and a merlyn waste gate.

I would like to know what manifold pressure and RPM to run. I would also like to know how to run

lean of peak. What is the best delta for this engine? If you have run a TSIO-360-LB1 engine to TBO, "without" having to

top the engine, you are pilot I'm looking to hear from.

[Parker_Woodruff]

@KLRDMD is the guy you want to talk to.

9-10 gph while LOP won't hurt anything.

[Bryan]

I have a 1982 M20K 231 with intercooler and merlyn wategate.  For takeoff, I run full prop forward (2700 RPM) and 36" MP being careful not to overboost. I use this all the way up until my cruise altitude.  I then level off, build some speed, MP back to 29" and prop back to 2500.  Close the cowl flaps and start leaning to peak.  I run 50-100° ROP for now.  Working on my GAMI FF spread and with more knowledge, I plan to run 50° LOP.  I have an Insight G2 engine monitor with full CHT, EGT, and TIT.  I never run my TIT past 1650° and my CHT much past 380°. I sometime have to trail cowl flaps at higher altitude to keep the CHTs below 390°.  This net's me about 12.5 - 13GPH in cruise.

My engine is a TSIO-360-LB7 with 1100 SMOH.  I get an oil analysis at each oil change (30-40hr) and run W100 Aeroshell during the summer.

PM me if you have any questions or want more information.

[KLRDMD]

1 minute ago, Parker_Woodruff said:

@KLRDMD is the guy you want to talk to.

9-10 gph while LOP won't hurt anything.

Everything at redline (2700 RPM, 37" MP and full rich at 25 GPH) and cowl flaps open for climb at 120 KIAS. Level off, close cowl flaps, MP back to 30", RPM to 2500 and fuel flow to 10 GPH or less.

10 GPH = 65% power LOP,  9.5 GPH = 62% power LOP and 9.0 GPH = 59% power LOP. I choose 9.0 GPH and 59% power as the most efficient. That will give you 160 KTAS at 10,000 ft. My CHTs are in the 330-350º range and TIT in the mid 1400s. EGTs are irrelevant. Add or subtract 2 KTAS for each 1,000 ft above or below that altitude.

Going from 9 GPH to 10 GPH increases true airspeed from 160-170 knots. That's an 11% increase in fuel flow for a 6% increase in true airspeed.  Pick your fuel flow and it will determine your % power when LOP. I do not fly, nor do I recommend you fly any version of a TSIO-360 at greater than 65% power in cruise. Doing so means you're buying at least one and maybe two top overhauls.

[jetpilot12]

1 hour ago, KLRDMD said:

Everything at redline (2700 RPM, 37" MP and full rich at 25 GPH) and cowl flaps open for climb at 120 KIAS. Level off, close cowl flaps, MP back to 30", RPM to 2500 and fuel flow to 10 GPH or less.

10 GPH = 65% power LOP,  9.5 GPH = 62% power LOP and 9.0 GPH = 59% power LOP. I choose 9.0 GPH and 59% power as the most efficient. That will give you 160 KTAS at 10,000 ft. My CHTs are in the 330-350º range and TIT in the mid 1400s. EGTs are irrelevant. Add or subtract 2 KTAS for each 1,000 ft above or below that altitude.

Going from 9 GPH to 10 GPH increases true airspeed from 160-170 knots. That's an 11% increase in fuel flow for a 6% increase in true airspeed.  Pick your fuel flow and it will determine your % power when LOP. I do not fly, nor do I recommend you fly any version of a TSIO-360 at greater than 65% power in cruise. Doing so means you're buying at least one and maybe two top overhauls.

That is exactly what I was wanting to know!!! Thank you very much for your time...

My next question is on the O2 system. I have never flown the Mooney that had one. All of my experience has been in a pressurized jet. Years ago I

flew a T210, but I had a portable bottle. Is it automatic system or do I need to manually regulate it?

[gsxrpilot]

27 minutes ago, jetpilot12 said:

That is exactly what I was wanting to know!!! Thank you very much for your time...

My next question is on the O2 system. I have never flown the Mooney that had one. All of my experience has been in a pressurized jet. Years ago I

flew a T210, but I had a portable bottle. Is it automatic system or do I need to manually regulate it?

You need to regulate it at each mask/cannula. I plan to add the Mountain High O2D2 which will make it more of an automatic system.

[peevee]

28" 2500 rpm and figure 14.5 to 15 gph.

That would give me about 190 true in ours up high. Guess I'm weird. I buy fast airplanes to go fast. Usually trailed flaps to keep chts in line.

 

If you can get a 252 cruise chart it's easier than messing around with the intercooler conversion stuff and you can use those settings.

[carusoam]

12 minutes ago, peevee said:

28" 1500 rpm and figure 14.5 to 15 gph.

That would give me about 190 true in ours up high. Guess I'm weird. I buy fast airplanes to go fast. Usually trailed flaps to keep chts in line.

PV, 2500rpm?

-a-

[peevee]

3 minutes ago, carusoam said:

PV, 2500rpm?

-a-

Yeah, that works better.

[jetpilot12]

2 hours ago, gsxrpilot said:

You need to regulate it at each mask/cannula. I plan to add the Mountain High O2D2 which will make it more of an automatic system.

Perfect! I just looked at their website, I plan on doing the same.

[peevee]

16 minutes ago, jetpilot12 said:

Perfect! I just looked at their website, I plan on doing the same.

Money well spent.

I have the o2d2 but precise flight has a mechanical setup, no batteries. See which you like best.

[urbanti]

Can 231s with -GB engine + intercooler + merlyn wastegate use the same numbers as -LB engined 231s w/ intercooler + merlyn wastegate?

Thx

Tim

[j3gq]

Hi, unless the question on best engine parameters is all solved, have a look at an article titled 'flying a 360', found at knr-inc.com under ShopTalk.

I think it holds a few extra / interesting thoughts.