Reply to "Cooling and ignition advance"

Well I wish you well with that combination.

There are other factors involved in that combination though. for one thing, the combustion chamber shape, flame travel, total cylinder pressure, and more.

I find a better combination considering the fuel quality most readily available, is a closed combustion chamber, 10-10.5:1 static compression ratio, a camshaft with overlap over 64 degrees and total advance of 34-36 degrees.

This gives you the ability to dial the advance down to a minimal of about 28 degrees in a fuel emergency, run pump gas, and still maintain a large percentage of the power of the engine.

With a built in 12.5:1 c.r., you have no flexibility with it at all. The only thing that might work would be to use alcohol injection?

I went that route with a 12:1 Cleveland with closed chamber heads and it wasn't enough. The only thing that worked was 106 octane gas.

That was $7.50 a gallon here so I would presume that is about what you would pay per liter for it in Europe?

That combination, 12.5:1 is the maximum mechanical efficiency you can build into an engine but with the cost of the 106 fuel, the cost makes it just an academic point to be made.

I got lectured by a refinery manager for Exon that to make that fuel it comes right from the top of the "barrel" and for every one gallon of 106, they could make five or more 87 octane gallons, and that would be "socially irresponsible" as far as he was concerned? Gee-ze!

At some point 92 is going to disappear for that reason I suppose?