I'm going to experiment a little.. out of necessity.

I have the intake side apart awaiting a J-spec manifold from mazdamotorsports to arrive. The manifold p/n: BP6Z-13-100 arrived. However, the surge tank, p/n: BP6Z-13-130 did not.



The inlet runners are quite a bit larger in the J-spec. A small portion of the intake runner resides on the surge tank half. However, it should be an easy task to port match and blend into the plenum with a grinder.

It'd be a shame to put that old restrictive manifold back on... so this should be fun. I'll do a token dyno pull and see what it does. Maybe it'll be j-spec performance at 1/2 the cost... or maybe I'll run into unexpected problems. I'll report back. If the surge tank dowes ever arrive, it should at least be an easy fix to pop on the squaretop surge tank...


... if it ever arrives.

The bottom manifold is a VTCS surge tank which came with my car. The top is a VCIS surge tank.






This is the J-spec intake.


EDIT: I hate to burst my own bubble, but after looking at the pics; there is no way that this is going to work... The surge tank looks to be quite a bit larger on the North America parts... I wish there was a delete post button!