That manifold also looks like poo, too They could probably get the clearance they'd need if they rotated it so the primary ports went to the outside, so the tall/thin runner wouldn't have to make a sharp bend there.

That's why I rather like the RB manifold.

BLUETII, you hit the nail on the head with respect why the 6 ports suck. Lots of internal surface area and very late timing. Whether or not Mazdatrix opened it up to one big port is neither here nor there, the point is that they started life as 6 port parts and all of the downsides (mega late closing) that entails.

I'm less than enthusiastic about the FD lower manifold. But then I have only ever seen the manifold and not a FD block, so I couldn't judge the way the port enters the engine. I understand the port runner is greatly angled upward, probably for turbo clearance since that angle is less than optimal for getting the air from the port into the chamber.

If I were a crazy mad scientist, I'd run a remote water pump and small flywheel, fill in the stock secondary ports completely, and make new runners coming in from the front and back of the engine. Not much can be done about the primary ports though

 

If I were a crazy mad scientist, I'd run a remote water pump and small flywheel, fill in the stock secondary ports completely, and make new runners coming in from the front and back of the engine. Not much can be done about the primary ports though


Ah ha ha! So I'm not the only one that had that crazy idea for side ports with a straight shot in.

 

It doesn't, found out many years ago.

 

The RB manifold will give you the LEAST amount of clearance for a turbo manifold that places the turbo hotside dead center, or forward (at the front intake runner), the JW will provide slight more clearance if the turbo hot side is placed in the in the center of the engine. The jay-tech/pro-jay provides the most clearance, but its still a tight fit for most aftermarket turbo manifolds.

Forget about using OEM turbo/manifold with any of these intakes, unless you custom make a spacer. Hint - hint, the spacer will need to be between the turbo and the turbo manifold, forget about a spacer between the engine and the turbo manifold!

 

Whoops. I guess I was only half right. Sounds like they will clear a turbo depending on the turbo manifold used. None will clear the a turbo using the stock turbo manifold.