I have a 57trim t04e wheel in a housing that has a flat, 3-bolt mount for the inlet, and an alumunum rod thats 4x49" to play with on the lathe. The bolt pattern allows 2.5" easily, but for 3" I'd have to make it cone-shaped on the outside. 4" is kinda out of the question, as I don't have 4" tubing (can't mount filt directly).


Would I see any extra gains out of a 3" tube vs 2.5", even if I use the same filter on the ~2.25" inducer wheel? Maybe its just because I like going the extra hard mile, and want 3"...

 

i would go with 3, i think 4 would be cool, and probablywould make spool alot louder