number of flow orfices

[Maxflow]

I have a orfice disc made from the mercdog plans.
my question is should i block some of the orfices or use
them all. It has 8 sizes. Range is from 7/8 to 3".

[MMack]

I am interested in this too. From some older posts, I was thinking about 4 plates. Mine are 7/8", 1-1/4", 2", and 3". This was to give about a 2:1 step up. The top of one will be the 50% of the next. These are home made in the shop at work, not the quality of Bruces plates, but should be a starting point. I am already over budget by a factor of 2-3 for this build and am running out of time to get my race car ready for the first outing of the year! They will work for comparative work, just not absolute. That will come later.

Mike

[200cfm]

On my bench I stayed with the number and range of orifice plates for the particular head I was most interested in flowing. And I had Bruce make up those sizes that would cover the lift range and still keep the range within the upper 60% of the incline. This aids in accuracy and allows good sensitivity to changes.