924doorEG

my head is about to go into the machine shop, what ports do you have them smooth down the exhaust or intake ports?

PhantomLord

Do both.

sohctodohc

no i think you want the exhaust to be smooth and the intake to be rough.

1992Si

oh god,

Do both... If the shop has to ask you better go some where else.

951BRO

exhaust smooth, intake more open and rough, but open both up a little

Magik123

just my 2 cents please feel free to debate but every honda motor ive seen port and polished ended up doin worse on the air flow bench.... from what i have heard honda designes the head to cause a swirling motion which builds pressure so when the intake opens again its kind of like F.I and smoothin the ports out negates this. Maybe with boost you wouldnt notice this ... ask the shop to flow bench b4 and after to make sure u got ur moneys worth

Preferio

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Magik123 &raquo;</TD></TR><TR><TD CLASS="quote">honda designes the head to cause a swirling motion which builds pressure so when the intake opens again its </TD></TR></TABLE>


Hahahahaahahaha...

forcefedferio

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Magik123 &raquo;</TD></TR><TR><TD CLASS="quote">just my 2 cents please feel free to debate but every honda motor ive seen port and polished ended up doin worse on the air flow bench.... from what i have heard honda designes the head to cause a swirling motion which builds pressure so when the intake opens again its kind of like F.I and smoothin the ports out negates this. Maybe with boost you wouldnt notice this ... ask the shop to flow bench b4 and after to make sure u got ur moneys worth </TD></TR></TABLE>

i have heard this is true and i have also SEEN it in action 4 honda heads, all being LS heads, all ported and polished and put on the flow bench before and after 2 of them flowed better beforehand without even any prior cleaning.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sohctodohc &raquo;</TD></TR><TR><TD CLASS="quote">no i think you want the exhaust to be smooth and the intake to be rough.</TD></TR></TABLE>

both smooth for fuel injection, it's carbureated you want the roof of the port to be slightly rough.

pimpinblackcivic

this thread could go on and on as theres two schools of thought on rough v smooth - i agree that its worrying that the shop are asking you!

MJ0LNIR

I was in on this thread until I read the posts.

Magik123

lol shoulda seen that comin .... but im just tellin u what i was told by a 23yr owner of a machine shop .... using the terms cuz its easy to understand

PhantomLord

Your going to gain most of your power by port matching the intake manifold to the head. Another good thing to do is to get rid of the casting lines inside the ports. As far as making the ports bigger all the way through, you will not gain much on an n/a motor. The reason people say not to smooth the intake to much is because the gas will stick to the sides of the ports more instead of going right into the combustion chamber. You definately do not want to pollish your intake ports to a miror finish or anything like that. As far as Honda saying they design the intake mani to cause swirling, I've worked on a large number of honda intake manifolds and never seen this. However all the intakes I have worked on have been older motors like the y8. The newer honda motors may actually do this. Not saying that Magik123 is wrong, just sayig that I think that only applies to the newer cars.