currently have a thread int he proejcts as im rebuilding my wrx forged. while i wait for things to develop im planning on doing the small details, that i cud possibly do myself.

so question is, do i port and polish??

some people say yeh, but just port.

but wudnt a polish make it smoother for for inlet air to get in faster and and exhaust gases to get out, so better breathing. better combustion in chamber?

 

Dont polish, an 80 grit finish is perfectly fine.

 

Have a read
DIY - Basic Cylinder Head Porting -Standard Abrasives Motor Sports

Mick

 

Be careful with DIY porting, you can do more harm than good with airflow, atomisation of fuel, burn properties within the cylinder etc.

Also, in some places on cylinder heads, the amount of material separating a port and water way may be pretty small, grinding it down could make it too thin so that it fails prematurely.

There is a lot of basic stuff that can be done, but most decent porters scrap many heads prior to selling a 'good' product by trying things out, testing on a flowbench for results, etc etc and often going back a few steps when things go wrong.

I've no experience of this myself, I don't have the knowledge to do it properly, but you don't need to do much in the way of an internet search and talk to forum members who've tried it and failed (Pug forum mainly).