All 3 here are Spyker impellers.
Left = current issue (2 curved/2 straight fins) = 11 7/8 inches
Middle = old impeller I found in our warehouse (4 straight fins) = 11 7/8 inches (this is what I want, but I could not find a Spyker part number on it)
Right = Spyker sent this to us yesterday (thank you). 4 straight fins. 10 1/2 inches. Also has 4 holes in it. ??? I'm concerned that it is only 10.5 inches in diameter, as well as 4 holes in it.
We will test the new Spyker impeller very soon -- not sure if the holes will be a factor or if the smaller size will make a difference. My guess is...it will, cuz smaller impellers usually mean narrower spread pattern.