Racing flow benches

That’s right Ratty!

A flow bench is nothing like a moving piston in the ‘down stroke’ cycle of an 4 stroke engine.
But everything is a compromise in life...lol...

So with hours of reading David Vizard books, I am going to use his “cheap as chips” engine bench for my first err bench?

I will fit a vacuum supply to floating piston in the bore and see what flow differences there are with the ‘valve opening’ and piston height?

There is little or no vacuum at the start of a cycle, only the exhaust gas firing out off the exhaust port, following many others on their way to freedom...lol

I believe someone has designed such a bench to discover what the exhaust pressure escaping, does to the start of the intake charge?

So the initial downstroke takes quite a while before the maximum vacuum is created, somewhere between half stroke, to ‘full’ with the inertia of intake charge following on behind.