What are the extra ports on either side of the exhaust main port for?

 

if you read in the saab 9-3 owner's manual, that's where you can stash drugs when sneaking across the border

 

no one?

 

OMFG that is hilarious!!!!!!!!!!!!!!!!

 

on a serious note, i'm not 100% sure but it's possible they are for some type of emissions/egr system. used to capture some of the spent exhaust as the valve opens and the rest goes out the port, those two chambers capture some of the exhaust and basically backwash it into the cylinder when the exhaust valve closes

that's all i got, but could be completely wrong

 

bump

 

oh cool ported head!

 

i would say a egr type system as stated or to relieve pressure if u get a backup of pressure there... feeds it back through... maby its a silencer of some sort... bump for an awncer and sorry i have no clue

 

bump

 

i spoke with my gm guy this morning, he said he wasn't sure but was thinking that it has something to do with 1 of two things.

1. just leftover from the manufacturing process to allow for expansion of the port or something of that nature

or

2. used for additional cooling, specifically because they were designed for turbos

 

On a flow bench these create a very high pitched sine wave that makes your ears ring. When you plug the wholes it drops about 5cfm.

Bump

 

bump

 

thats interesting

 

already mentioned what the gm guy said, i'd take his word over anyone else... he's got a masters in automotive engineering and been a union worker with gm for over 10 years

 

correction it was 5% flow so more like 10cfm