A normal 12a has a four-port intake manifold, this is understood. But right below the two center vertical ports is a horizontal one, which I'm assuming is the EGR port. Is this right? Becauce I thought that California cars were the only ones meant to recylce their own waste? I read it some where, not sure where at this moment. And lastly does this apply to J-spec 12a turbo-ized verisons?

 

Its actually an air injection port. The later 12A's had this (81-85). The air pump air can be routed to this port, or to the precats, or the main cat.

 

Oh cool. I have always wondered what that was.

 

Hmm, didn't know that. Just thought the air inject. would go either to the pre-cat or main cat. I'll sleep better. Thanks.

 

But then was it used to raise idle by increasing air volume? Or to pump slightly warmer air during start up? And wouldn't adjusting the choke provide the means to up the idle to warm her up quicker?

 

I think (but dont quote me) that is was used to port airpump air earlier to the pre cats during warm up.