I know this has been beaten to death, but hoping for some input on my engine.
About to pull the trigger on a Lyc 540 Thunderbolt. Cold Air Intake, SDS Efi/Ignition. My important requirement is upper altitude efficiency. Don't care about max power. I want it to be MoGas compatible. 91E0 and 91E10 is available locally.
First thing I'm not familiar with - when you go to an airport with MoGas, what octane do they typically offer?
As for engine compression ratio. Since the RV-10 is a good higher-alt cruiser, a higher compression ratio should be able to squeeze a little more work from the fuel at those alts.
My first thought was lets try 9:1, as some have had success with that. Ross from SDS told me that would work, we would just reduce timing at high MAPs as a buffer against detonation. Others say 8.5 is good and should be rock solid with plenty of margin. I could also split the difference at 8.7, but what I don't know is the real improvement when bumping up these numbers. Its been said that past 9:1 the returns diminish.
Another factor I'm thinking about is the recent Kitplanes article says that Cold Air Intakes give you a little more margin against detonation.
So I'm torn. Since this is one of the single most expensive things I've ever purchased, I'd like to get it right the first time. Any thoughts or advice from the community?
About to pull the trigger on a Lyc 540 Thunderbolt. Cold Air Intake, SDS Efi/Ignition. My important requirement is upper altitude efficiency. Don't care about max power. I want it to be MoGas compatible. 91E0 and 91E10 is available locally.
First thing I'm not familiar with - when you go to an airport with MoGas, what octane do they typically offer?
As for engine compression ratio. Since the RV-10 is a good higher-alt cruiser, a higher compression ratio should be able to squeeze a little more work from the fuel at those alts.
My first thought was lets try 9:1, as some have had success with that. Ross from SDS told me that would work, we would just reduce timing at high MAPs as a buffer against detonation. Others say 8.5 is good and should be rock solid with plenty of margin. I could also split the difference at 8.7, but what I don't know is the real improvement when bumping up these numbers. Its been said that past 9:1 the returns diminish.
Another factor I'm thinking about is the recent Kitplanes article says that Cold Air Intakes give you a little more margin against detonation.
So I'm torn. Since this is one of the single most expensive things I've ever purchased, I'd like to get it right the first time. Any thoughts or advice from the community?