Orifice Plate

[johnta1]

On another forum, someone wrote this:

For example on my flow bench that I made i-flow 300 CFM heads with a 700 CFM test orifice. The reason is that I found with increasing the test orifice size I was able to pull a higher depression cross the cylinder head with same WORK applied by my vacuum Motors. And I found accuracy did not change.

Comments?

[storm]

Can you provide the context that was written in reply to?
In other words provide a link to the actual thread so we can see what was actually being discussed.

[Tony]

It probably worked fine flat out at 300 CFM, or 700 CFM or whatever it was.

But I would like to bet both orifices did not read the same at 20 CFM.

[johnta1]

Can you provide the context that was written in reply to?
In other words provide a link to the actual thread so we can see what was actually being discussed.

Thread

[storm]

johnta1 I see you don't need help getting a barny going so I am going to limit my input here because after reading that thread and seeing the antics pulled I'm not really all that interested in getting into a discussion about it. The fact you have posted that without showing the context of the discussion speaks volumes to me.

For everyone else johnta1 is talking about something John Marcella posted on maxperformanceinc forums. For what its worth I have always found both individuals to be very informative but I found the rubbish posted in that thread infantile and I'm simply not interested in watching material posted here used there as a weapon.

[johnta1]

That is why I posted it here?

The infantile antics there usually derail topics all the time.

I figured here there would be more intelligent people.
(I also didn't mention any names or link until you wanted it)


This is what I do not understand?

increasing the test orifice size I was able to pull a higher depression cross the cylinder head with same WORK applied by my vacuum Motors.

Why would anyone buy the bigger (more) vacuum motors if it wasn't necessary?

Or even use different plates?
(for more accuracy?)

[storm]

That is why I posted it here?

The infantile antics there usually derail topics all the time.

I figured here there would be more intelligent people.
(I also didn't mention any names or link until you wanted it)

Context is everything, the way you started this thread triggered red flags. If you had been upfront from the start I'd be thinking very differently now.

This is what I do not understand?

increasing the test orifice size I was able to pull a higher depression cross the cylinder head with same WORK applied by my vacuum Motors.

Why would anyone buy the bigger (more) vacuum motors if it wasn't necessary?

More vacuum gives more opportunity to test at a variety of different vacuum levels. Engines don't always run at 28" H2O so exclusively testing at 1 level doesn't show the full picture. That however, to me, is beside the point. Why? by the quote you just gave he didn't buy bigger or more vacuum motors. What he says he did was change the test orifice size and obtained a higher depression with the same level of work from the motors.

Or even use different plates?
(for more accuracy?)

To change the amount of vacuum and/or flow.

Why don't you ask John Marcella? If you keep your tone neutral, and don't irk people, on the other forum you may actually get a civil answer.