Do you run your Bravo LOP?

[Rick Junkin]

I’ve run my Bravo LOP since I bought it in 2016, following the guidance provided here on Mooneyspace by @DVA and @Awful_Charlie to get my engine set up for it. I run Tempest fine wire plugs and went through four iterations of GAMI injector swaps to get a GAMI spread of 0.3gph. I have the magneto timing checked every 50 hours.

I typically run 30/2200 and 40 degrees LOP at ~1585 TIT with all individual EGTs at least 30 degrees LOP. Fuel flow averages 13.8gph and CHTs are in the 330’s. At 16,000’ this yields 143KIAS with true airspeeds in the 175 knot area, +/-. My technique is to set 30/2200 once reaching cruise altitude and airspeed and stay full rich with the cowl flaps open until CHTs drop and stabilize, then pull the mixture straight to ~13.8 and then adjust to get 1585 TIT. CHTs stay in the 330’s and the engine runs smoothly.

I can run 32/2200 and get a few more knots, about 150KIAS, but the 40 degree LOP TIT gets into the 1600’s and the CHTs rise to the 350-360s. Those temps are fine, but I’m able to run cooler and am seldom in that big of a hurry so I run at the lower power setting. I like the noise reduction I get at 2200 RPM.

Cheers,
Rick

[mike_elliott]

Blasphemy Rick. If your going to post anything about TAS and you own a Mooney, dont forget the obligatory embellishment of at least 15%  

[Rick Junkin]

17 minutes ago, mike_elliott said:

Blasphemy Rick. If your going to post anything about TAS and you own a Mooney, dont forget the obligatory embellishment of at least 15%  

Yeah, that’s why I like to to reference KIAS at given altitudes. It’s more apples to apples with less variables than the KTAS numbers folks like to use. If anything I usually understate my KTAS to worst case temperatures, as in my above post.

Cheers,
Rick

[mike_elliott]

You can fudge there also by cracking the Alt air to insert the proper weenie wag.

[PhateX1337]

6 hours ago, Rick Junkin said:

I’ve run my Bravo LOP since I bought it in 2016, following the guidance provided here on Mooneyspace by @DVA and @Awful_Charlie to get my engine set up for it. I run Tempest fine wire plugs and went through four iterations of GAMI injector swaps to get a GAMI spread of 0.3gph. I have the magneto timing checked every 50 hours.

 

Just curious - what's the proper timing for our Bravos? 20? 25? I'm planning on having this checked next time I'm in the shop.

[Rick Junkin]

9 minutes ago, PhateX1337 said:

Just curious - what's the proper timing for our Bravos? 20? 25? I'm planning on having this checked next time I'm in the shop.

20 degrees BTC.

[Rick Junkin]

Here's some empirical data to add to the Bravo LOP discussion. I took this screenshot the other day. The display shows how far each cylinder is LOP, and the TIT is about 50dF LOP. Unfortunately extreme high winds at altitude drove me to cruise much lower than usual. I'm really liking the G3X Touch and the EIS capabilities.

Cheers,
Junkman

[Schllc]

Ooo, I like that engine page more more than the one on my 500txi. 
Now I need to crack that tome to see if I have options!

[Dsal1]

I have an Electroair EIS and fine wires on them but massives on the top mag fired. I have GAMIs.  I have run loo no problems at 30 or 32 inches and 2200 rpm. I run about 12.8-13.2 gps at 150-155 ktas. CHT’s  run 330-350 and TIT about 1610-1630. I make a big pull at cruise with cowl flaps closed from 18 my rop cruise flow to 13 gph and adjust to TIT under 1640

 

[Jetpilot86]

I've been consuming everything on here and anywhere else I can find it, in order to validate the various engine operating techniques for the Bravo out there.

I've got roughly 60 SFOH on an engine that had 10 SFOH when I bought it.  Still waiting to get my new Insight G4 installed so I can seriously explore LoP, but I've gotten some good work in with my G2 with just CHT/EGT hooked up.

Now, I haven't added GAMI as I'm at .5 gph in the sweep with the OEM injectors.  I have added FineWire's.  If anyone is looking for some low time Massive's, let me know, I've got a dozen currently stored in the old Tempest packaging.  

I'm able to run 30"/2200 with that setup, 50F LoP, smoothly.  I've gone way leaner than that and was shocked at how low the flow got before I started running rough enough to care.  I was running 166KTAS on 14.2 gph, in line with @Rick Junkin.  That was 11500', ISA +6 with 335dF on my fiesty #6 EGT and a 1525dF TIT.  I've got more work to do, higher, still, but I've got a baseline now.  If your glass turns up missing, "I know NOTHING!" 

I'm currently working on reverse engineering a power chart from the POH/EOH combo, lets just say neither Mooney or Lycoming has made it easy.  I'll share it on the board when I'm satisfied it's ready for MS scrutiny. It will confirm some things, and challenge others.

What I'll say I've discovered so far is that if you're going to try LoP, I strongly recommend a 2200 RPM power setting.  This helps with Red Box issues by allowing the combustion process to take a little longer, and creates a little less stress on the engine at the higher power settings vs the 2400 rpm settings.  That info comes from some mixture of Busch and Deakin articles I've read.  Don't recall the exact reference at the moment.

Another thing to keep an eye on in the Lycoming Engine Manual attached, is that the HP's are dynamic with altitude, so at low altitudes some power settings may start clear of the Red Box, only to end up in the Red Box as you climb into the teens.  There are some possible work arounds that I'm currently researching.

For the new Bravo owners, the challenge it seems, when running this engine is that you simply cannot focus on one parameter, especially TIT for a "quick" set solution without knowing it's relationship to EGT, CHT and Oil Temperature, especially as you start getting above Key 50, or 28"/2200 and above if you don't know the key codes yet.  I suspect that as you get above Key 53 or so, it becomes less possible to run the power setting at anything less than Full Rich on the mixture to keep away from the EGT's Red Box.  Once you learn how those parameters all intertwine, then you can understand why the high time Bravo owners can run theirs off one number, TIT. 

TIO540-Engine Manual.pdf