Are there any Engine / “Air in” Wizards out there?

I have a 900 with a Trinity Stage 5 exhaust and an RVS tune. RVS recommends a modified intake. I am going to replace the factory weird shaped plastic thing to an aluminum pipe, from the air box (2.5″) to the intake (2.25″).

My question is from the air box to the “fresh air” do I go 3″ or 2.5″? the opening to the air box is 2.5″, do I just carry that up and will it suffice? or should I give it a little extra space and do a 3″?

Any input would be great! Math or real world test would be best!!

Thanks in advance!

Scott

Utah RZR Rentals

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