pierre smith
Well Known Member
Reason for the question comes after I had spoken with Don at Airflow Performance this morning. I had methodically leaned by .2 GPH until all the cylinders had peaked and faxed the results to Don, so we could tweak the injector inserts....some cylinders were 130 degrees cooler than the peaked # 3 and 5.
I asked him about how far LOP to run once we had done the tweaking and he asked if the Dynon 120 had a MPG calculator and I replied that it did. He said that the most efficient LOP position would be the highest MPG number...and that when it starts dropping off, I'd leaned too far.
I wondered whether that might be in the 200-300 LOP range or what but he said that it didn't matter, just the best MPG...Hmmmm...hadn't ocurred to me but I do see an airspeed loss, running lean of peak and obviously, that's because we're making less power. So, it depends on whether you want the fastest speed or the most bang for your avgas dollar...your call.
BTW, even at 23" and 2400 RPM, 3500', the engine ran all the way down to 10.8 GPH but was getting rough and rather slow. Lyc IO-540.
What say y'all?
I asked him about how far LOP to run once we had done the tweaking and he asked if the Dynon 120 had a MPG calculator and I replied that it did. He said that the most efficient LOP position would be the highest MPG number...and that when it starts dropping off, I'd leaned too far.
I wondered whether that might be in the 200-300 LOP range or what but he said that it didn't matter, just the best MPG...Hmmmm...hadn't ocurred to me but I do see an airspeed loss, running lean of peak and obviously, that's because we're making less power. So, it depends on whether you want the fastest speed or the most bang for your avgas dollar...your call.
BTW, even at 23" and 2400 RPM, 3500', the engine ran all the way down to 10.8 GPH but was getting rough and rather slow. Lyc IO-540.
What say y'all?