LOP

[Simon Hitchen]

Hi guys,

I’m running a Titan IO-360 with an Avstar FI unit monitored by a dynon skyview. In the cruise I lean the engine to LOP and then continue to lean until the first cylinder to peak (#4) reaches 50 LOP. The engine runs beautifully at around 7- 7.5GPH but this leaves the last cylinder to peak at around 20 LOP I think i May be doing this wrong...should I be continuing to lean until the last cylinder to peak is running 25-50 LOP? This would leave the first to peak at around -80 LOP.



Many thanks

Simon

[pa38112]

Either is fine, because 20 lop is a safe operating range, however, the last one to peak is putting out more power than the others, so that is the one you use to set your cruse power.
I would balance your injectors to try to get them running closer. What is your FF spread from first to peak to last?

[lr172]

Your #4 injector can be re-sized to bring that cylinder in line with the others if you desire and will save a bit of fuel, though it is not necessary. You should not worry about the different LOP values across cylinders, as long as you are below 75% power (no mixture setting is dangerous below 75%). Adjust mixture to the performance level that you desire (speed vs FF) without concern for the disparity. Yes, the #4 is making a tad more more power, but this is of no concern; Stock lycomings typically exhibit this and often MUCH worse.

My peaks are a bit tighter, but not perfect. Also, my cylinders peak a different temps. I routinely do all my leaning work by watching my #4 (it is hottest) and adjusting it. After a while, you will learn how to manipulate that temp to get the desired performance in various different flight conditions. If you have a modern EFIS, I would encourage some experimentation with different mixture settings/altitudes. The EFIS can often help you find optimum via a MPG function. At 8-9K, I find 20 LOP to be about the most efficient, so that is where I cruise.

Also, it is ok if 1-3 are 20 LOP and #4 is at peak. This is of no concern when below 75% power and I often cruise at peak EGT when in a hurry or at higher altitudes (12K).

Larry

[Simon Hitchen]

Great advice, thank you