how much can I push a 231

[gabez]

So I usually run 31/2500 and 13.3FF 125 ROP (TIT). I was looking at the attached chart, can I really go 90% power? Like 35/2700?

[Hank]

I generally don't push my C much more than 100 feet, otherwise I crank up and taxi.

Each year it seems that my changeover point gets shorter . . . .

[carusoam]

All Mooney’s have two methods of operation…

1) keep the cylinders cool to get as close to 2k hrs as possible…

2) keep the TIT cool to keep the vanes from elongating into the turbo’s case…

3) Some use LOP for this…

 

then there is full on flaming dragon mode…

find the threads about operating the 231’s engine…

find @jlunseth’s writing….

 

Best regards,

-a-

[kortopates]

Of course you can. Don’t you already climb at 100% anyway? Sort of the same thing in that you can cruise that way too if you want. But do recognize any power setting above max cruise requires full rich mixture as mentioned in the table. Your cruise table list the max cruise power setting permitted with leaning.


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[hubcap]

If you run your 231 at 90% power for long periods of time you will be working on your cylinders shortly. 

[Shadrach]

28 minutes ago, hubcap said:

If you run your 231 at 90% power for long periods of time you will be working on your cylinders shortly. 

Is it that they’re always going to be hot at 90%?  
 

I would have little concern running my NA cylinders at 90% for extended periods.

[carusoam]

2 hours ago, Shadrach said:

Is it that they’re always going to be hot at 90%?  
 

I would have little concern running my NA cylinders at 90% for extended periods.

Ross,

in our NA world…. We get dense air while at 90%bhp…

Our TC’d brethren can get lots of power up where the air is too thin to provide adequate cooling…

 

done well, a tc’d engine can use a set of cylinders around the halfway point to MOH…

not done well… the first TOH is before the half way point…

 

the intake systems of the six cylinder Continental engines are nicely designed to easily run LOP…

Best regards,

-a-

 

[gabez]

Thank you all, I do climb full power and my cylinders tend to be on the cooler side 350-360. I may experiment a bit but def will be doing more research through the forum 

[Pinecone]

But look at the fuel flow.  20.6 GPH.  That would keep me from running at 90% power.

My 252/Encore manual has a maximum recommended power of 75%

[Shadrach]

20 hours ago, carusoam said:

Ross,

in our NA world…. We get dense air while at 90%bhp…

Our TC’d brethren can get lots of power up where the air is too thin to provide adequate cooling…

 

done well, a tc’d engine can use a set of cylinders around the halfway point to MOH…

not done well… the first TOH is before the half way point…

 

the intake systems of the six cylinder Continental engines are nicely designed to easily run LOP…

Best regards,

-a-

 

You’re kind of making my point. It’s likely not the power, it’s the heat.

[jlunseth]

I also climb full power, full rich to whatever cruise altitude I intend to fly. That can be a prolonged operation, as much as 45 minutes if going to the 20's. That is not to say it is the best way to cruise an engine though, it is just the best way to climb over other methods that result in high temps. The POH also says you can push the cylinders to 460 dF as a redline but that does not mean you should, and I can tell you from personal experience when I first got my aircraft the engine won't melt or come apart, but it also is only good for about that one flight before needing major work. I am sure if your A&P sets the fuel flow high enough you can probably run near full power at cruise and still keep the temps cool, but why? - unless you like paying fuel bills. That is sort of the point of cruise power settings, one of the points anyway, that is - it takes an awful lot of fuel to push the power up to the limit for what, maybe a 10 or 15 knot advantage?

There has been quite a bit of experience with pilots flying all the turbo Mooney models at full throttle just to get the speed. I am not an A&P, I don't do the overhauls, but I have heard way too many stories from A&Ps who do about turbos run to the max needing top overhauls and/or turbo overhauls at an early age. Don't believe everything you read in the POH. There has been a bad history of outcomes where the POH says something that marketing wanted, but that sacrificed engine life.