Do all bases have the cold start holes in each runner? Or did they change the casting after they got rid of it?

 

I understand why aftermarket bases have them, but I can't see why they'd continue to machine the holes with no more cold start in 89 or w/e.
edit: to be clear I'm talking about the small holes inside the pipe plug holes.

 

I'll assume all basses had the holes now since the pcv also used them.

 

Those are EGR passages, not cold start.

 

No they are CS

 

Was talking about small holes underneath in the pic.
The ones in the upper plenum are IAC holes, side is CS.
Got your runners opened up nice at the face.

 

Me too and follow those holes, the small holes connect to the pvc and CS only. The only way they'd get egr gases is if it went out the TB throttle bores and then back in the iat/cs passage. If you tape off the inside of the runers and pour liquid down the pipe plug holes it'll come out the CS side and the EGR will be dry.


Those pics are random examples, I would never port it to that volume for only air! People shouldn't compare the cfm of a tpi base to a carb/wet flow intake.


edit: Well I guess it could pull egr gas from another runner since all 8 small holes are connected by that passage, but those egr gases would originate from the two holes at the mouth of the plenum and travel down each runner 1st.