So both my buddy and I are both BAR'ing b18c's in our eg's, and both of our heads are at Portflow (his is actually going this week).

My head is just getting Toms cleanup/refresher with his valvetrain, and my buddy is planning on getting the standard honda port/polish package also with Toms valvetrain.

Well, he and I have been debating on how much, if any head porting is going to affect emissions since the air flow volume and/or efficiency is going to change with his ported head.

Can someone here with some real knowledge in this area help us out. Also.. if anybody here has passed the BAR test with a ported head, speak up.

TIA and Appreicate any help.

 

no one?

 

The thing that came to mind is when you get more air in it will raise the compression a little and then this extra comp. would increase the nox output a little.

Same thing with a milled head. You shouldn't have a problem with a new cat. and retard the timing a degree or two

 

Thanks for the info.