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Hi all. I have a question regarding the intake manifold for my NB8A.
I was planning on swapping it with the square top as I have one available.
Am I correct by saying that my 98 model has VICS and the donor I'M from the vvt head does not have VICS but VTCS instead.
If VICS is to add perpormance at a certain rev range would I benifit or not from installing the square top?

Thank you.

The stock ECU and intake assembly for the NB8A is designed to work with the VICS. The VTCS isn't a performance feature, it's an emissions feature. No idea how the NB8A ECU would deal with it.
IM swaps are for the guys running big HP/turbo builds looking for more flow. I wouldn't recommend all that work to either make less power, upset your ECU or both.

Both are ways Mazda used to spread out he power delivery

VICS used butterflies in the intake manifold to change the length of the intake tract, allowing it to pickup a little power at lower revs.


VCTS allowed the intake cam to rotate a little, changing the cam timing, to allow cam timing more suited to lower revs and then change to suit higher.

So basically, both things did the same thing, just in a different way.
Kind of like painting with a brush or roller, both put paint on the wall, just in different ways.


As for swapping manifolds, the non vics manifold allows greater peak power from memory, but of course only if the current manifold is limiting power in some way. Which is unlikely on a standard engine.

And yeah, you'd be wanting to tune the car to suit whatever manifold is fitted.

Awesome and most informative straight to the point.
Exactly what I was after. After exhausting my searches This was the final piece of the puzzle I needed to make a decision. No one ever mentioned that I needed a tune or may run into bad ecu codes etc.
I guess I'll hold onto it though and use it to build my next engine. The reason I have the square top is that I've got a nb8b which I'm taking the bottom end and adding it to my bp4w head atm. But that's another topic I guess...
Many thanks for the replies guys...
Cheers!

Why are you changing the bottom end over? Just for the higher compression ratio?

VTCS is purely an emissions thing and as far as I'm aware the only cars that had them here are the SE. All nb8a should have the VICS with butterflies in the intake manifold that open up a second Helmholtz chamber while all nb8bs should have a "flat top" manifold with larger intake runners and no butterflies.

hks_kansei you're getting confused with VVT. VTCS manifold has butterflies just before the intake ports that close during cold starts restricting air flow.

VICS gives better midrange torque and a flat top better top end.

Ahh, didn't realise there was a 3rd thing used for the se.

I assumed he meant nb8a vics vs nb8b cam timing

If you still have the stock ecu just give up on last few percent mods like IM.

Dann

Yep. I'm changing the bottom end for the higher compression but the main reason is that it's going "Knock Knock Knock"
I have the NB8B motor already.
So in the middle of the swap.
Water pump
Timing belt and all belts
Clutch
Flywheel
Etc etc...