Is Polishing 5k Ports Beneficial?

[jaYmo]

I'm wondering whether to get the ports on my 5k cylinder head polished or not. I've been searching the net for info regarding this and a good piece I found (on WIKIPEDIA) was this:

 

The reason that polished ports are not advantageous from a flow standpoint is that at the interface between the metal wall and the air, the air speed is ZERO. This is due to the wetting action of the air and indeed all fluids. The first layer of molecules adheres to the wall and does not move significantly. The rest of the flow field must shear past which develops a velocity profile (or gradient) across the duct. In order for surface roughness to impact flow appreciably, the high spots must be high enough to protrude into the faster moving air toward the center. Only a VERY rough surface does this.

 

My question is, does anyone know if factory-standard, K-series cylinder head ports fall into the VERY rough surface catergory? (Enough so to justify polishing the ports.)

 

Thanks.

[love ke70]

its not the roughness that is the key issue in my opinion but more the shaping.

upping compression, and porting the shape does see some benefit.

 

basically, if its a stock motor your doing nothing to then just leave it how is, but if your working the motor, a good port and polish wont hurt

[Guest Sbox]

Deleted

Edited May 24, 2008 by Sbox

[mikeys toy[RL]]

exactly; polishing exhaust ports is fine, but not intake

[Guest Sbox]

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Edited May 24, 2008 by Sbox

[Guest Sbox]

Deleted

Edited May 24, 2008 by Sbox

[kangaroosa]

its not the roughness that is the key issue in my opinion but more the shaping.

 

I agree. This is my head and it seems to work very well. The ports are pretty much straight, as you can see. The ports are still roughened up to aid in atomisation.

[Guest Sbox]

Deleted

Edited May 24, 2008 by Sbox

[tas_ae71]

from what i know you need to have a good port and polish if you have a high revving na motor or turbo (increase flow, decrease presure from restriction), where it max air flow is needed...

 

so in my opinion, unless it has big dags, from poor manufacturing, should be fine, unless you are chasing big power with other internal work...