All well said Guy. Nice to see you again, so to speak.

There were (are) two ideas here about tuned intake and exhaust. One is to make an Nth engine more efficient, the other is to make more power. I am not interested in making more power as the 6-1 is not designed to make appreciably more than 6 hp at 650 rpm and my observations are that if it does it's dangerous. And then too, 6 hp is plenty, imho.

I agree with what you said, but would point out that making an Nth engine more efficient saves fuel. By transferring the pumping work from the flywheel to the waste acoustical energy a saving of something like 750 watts of power may be possible. This figure is mooted as an estimate only, but it's not simply a guess.

Most of the fluid loss in a diesel occurs in the exhaust - hence a tuned exhaust is the most profitable aspect to address. In an ideal engine one would exhaust to vacuum. In the case of the lister type 6-1 exhausting through 2" schedule 40 pipe the numbers for my setup seem to be as follows: exhaust event = 325 hz , pipe crossectional area = 3 sq inch, exhaust pipe length = 4.345 inches, exhaust temperature = 400C

I used the cavity resonance calculator found at

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/cavity.html#c4and the numbers I give here are a little rough - for example the area is not quite precise. The cavity in question is the cylinder itself - and I'm making assumptions about valve timing and overlap, etc. - the pipe length calculated is only approximate - but it gives an idea what is, I think, realistic. A second chamber, or "cavity", is obviously desirable for practical reasons - and it ought to be possible to calculate that so that it interacts to improve resonance and efficiency further as well as silences the gas pulses to minimize noise.

I am a bit out of my depth in this matter - but at some point in the process it may be that I'll either determine that tuning the fluid flow paths is useful or not - and, if worthwhile, by what number, ie how many watts are there for free. I pay over a grand for a couple of hundred watts of solar panels - this looks like it is worth investigating and, if the numbers crunch right, physical testing of theory and so on.

It's an evolving process... Best, P