Hey guys.
I just recently got a Imagine Engineering header from Ranta. Looks great, i can wait to get it on. But i was checking out my port sizes with the exhaust manifold gasket. And it seems to be off by a few mm. Mostly on the top of the port on the head. So what im saying is the header ports, are bigger then my head ports. Aslo i have alot of carbon build up.
Now im not stupid, Im not just gonna start grinding away and see what happens. But i do have alot of experience grinding stuff, and i modified my intake manifold very well.

My question to you is this. If i made the ports on the head bigger, only on the very outside of the head(not going in too deep) Will that effect the flow of the head? For the GOOD? haha.
I mean all i want to do is make is so there isnt a difference, and if just flows smoothly. Im going to be doing the same thing on the intake side as well.
lets get some feedback, and some flaming (dont do it unless your a proffesional BS)

thanks,

 

OH BTW, the way i would do it is put the exhaust manifold gasket on the header, and make it the shape i want, then put it on the head, so i can see where to grind away.

 

i did this on a chevy head, but when it came to my h22 i was told not to because of the good design to begian with.


i wasnt sure so i didnt mess with it...

 

Yeah, having the header ports slightly larger than the head is an anti-reversion technique - supposed to be good for performance.

I'd check with Imagine Engineering, see what he says.

 

maybe, hopefull ranta sees the thread and drops some info

 

It is good to have your header ports bigger than your head ports so that the air flow isnt interrupted. I would leave it like it is unless you make sure the head ports are slightly smaller than the header ports still after grinding.

 

http://theoldone.com/articles/h22a_head/

 

niiiice

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Daemione &raquo;</TD></TR><TR><TD CLASS="quote">Yeah, having the header ports slightly larger than the head is an anti-reversion technique - supposed to be good for performance.

I'd check with Imagine Engineering, see what he says.</TD></TR></TABLE>

Reversion occurs when the exhaust gases contaminate the intake charge, If we were talking about the INTAKE manifold then I would try to make the port a tad smaller then the head to combat this , it has nothing to do with your header.

I don't know what else is done to your engine but if the car is stock I would leave the exhaust port alone it tends to make the car a little lazy in low rpm by making the exhaust port as large as the gasket on stock engines. but if it is modified and
if you decide to port match the exhaust side, the grinder is in you hand and you say your comfortable with it, I suggest porting the whole exhaust port not just part of it.

 

The header ports are made slightly bigger because it helps reduce the amount of exhaust that will come back to to head from the primaires. That lip creates a small wall which will disrupt the flow and help stop it. When its flowing the other way it won't change things. The reverse of what HEAD said about the intake manifold ports being smaller than the head ports.