| I just found out a lot about this...
There is NO direct relationship between Holset's measurements and A/R. And even two different model Holsets with the same ex measurement will have different A/R. The only way to tell what you have is to measure it; either with expanding foam molds or other methods.
I was told the approx A/R of a HX35W with a 16cm^2 housing is .90-.95,
14cm^2 is ~.80 A/R, and 12cm^2 is ~.70 A/R.
That sounds about right.
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