I was doing some research on the APV assembly and I noticed that Mazda has a different part number for the S2 barrel assemblies. I wonder what the differences are and if the S2 barrels have a better flow to them.

Anyone had / have an S2 engine with access to the APV barrels to get some pics of the ports (in the barrels) to compare to the S1 assemblies?

Part Number Description Qty. Notes
N3H2-13-B6X Valve Assembly (APV) - Front 1 2004-2008 with High Power
N3H3-13-B6X Valve Assembly (APV) - Rear 1 2004-2008 with High Power
N3R4-13-B6X Valve Assembly (APV) - Front 1 2009-2011
N3R5-13-B6X Valve Assembly (APV) - Rear 1 2009-2011

 

You are heading down a dead end street

 

Most likely. Was more just curious what the difference in the parts was if any.

 

It's not a flow situation, just minor revisions. The flow is dictated by the length and diameter of the intake runner. An S2 doesnt make any more high rpm power than an S1.