gcc, 68K and ignition advance

[Nate]

On Tue, 29 Nov 1994, Wouter de Waal wrote:
[in part]

> * The air/fuel mix takes a constant _time_ to burn.

But the time it has to burn changes with RPM doesn't it?

> * Now obviously, you can't fire the plug before the inlet valve is closed.

Why not? How far is it from the plug? Doesn't it take a while for 
pressure to get there? The valve doesn't "snap" on and off, it takes time 
to close too.

> * And the next tricky point - vacuum advance. The vacuum is an indication
>   of engine load. But why is it a good thing to advance the timing when
>   the engine is loaded?

Some one probably already jumped on this, but it's the venturi vacume, 
and it increases as you suck more air into the carb.

If you could get two carbs off of some newer cars, you could control the 
mixture with your computer too! It might be real fun!