Dyno testing w/ knock sensor for fuel mapping?

[Westward_Flyer]

Hey everyone,
I'm still in the planning phase of a Model 5 build but I've been thinking alot about engine choices. In general aviation we leave a lot on the table in the interest of safety margins in terms of efficiency, power, fuel choices etc. Now this varies quite a bit based on your mission, for me I will be in Alaska so ethanol does not come into the equation but I would like to have a safe, reliable engine that can run various fuel types without sacrificing too much power.

Goal: IO580 w/ EFII that can run reliably on 91 octane up to 100L, compression ratio TBD
Plan: port and polish (lycon or barrett?) and dyno testing to generate safe fuel maps that maximize power without engine knock/premature detonation.

Would it be reasonable to run the engine on a dyno with various fuel types and a knock sensor to determine the points at which there is engine knock to develop fuel maps that maximize power? In an ideal world we would have knock sensors that function in real time on the aircraft and full authority EFII more like modern engines or even the GAMI Prism system but none of those options seem to be viable any time soon.

Thanks for taking the time to read my ramblings, any input is much appreciated as I learn more about all of this!

[svyolo]

My understanding is that Lycs and Conti's are too mechanically noisy to use a knock sensor. I am still running fixed timing on my SDS/540. SDS has a fairly simple procedure to see how much advance you can run. I will start doing that hopefully in a week or two after I sort out my CHT's. Almost there. I can't speak too much about operating EFII, but the way they run are mostly the same.

[Westward_Flyer]

My understanding is that Lycs and Conti's are too mechanically noisy to use a knock sensor. I am still running fixed timing on my SDS/540. SDS has a fairly simple procedure to see how much advance you can run. I will start doing that hopefully in a week or two after I sort out my CHT's. Almost there. I can't speak too much about operating EFII, but the way they run are mostly the same.

I've heard that too, I assumed that that was due to harmonics and such with the prop interacting with the engine. If thats the case then running it on a dyno might allow the knock sensor to function for the sake of developing fuel maps but not when in use after with the prop? But if its simply due to the engine then I guess thats a no go. I'm very interested to hear how your tuning goes, please keep us posted!

[noema]

FYI, there is a bit gotcha between US and Europe anti knock number. For example my an YO-360 needs at least 93 octane rating. You would think that 95 is then sufficient. But Europe uses RON and the US and aviation uses AKI: 98 RON ≈ 93 AKI (sufficient); 95 RON ≈ 91 AKI (insufficient)