Port matching / porting?

[evil_demon_01]

What is the difference?

Is port matching - where the head outlets are enlarged to the header port diameter, and the porting continues about halfway back into the ports?

And is porting where the ports are enlarged right up to the valves?

I have just started doing some, from what I can gather "port matching"?
Also, what (if any) results do you think I will expect to see from enlarging the ports out to the blue lines in pics below (I've already done #4 exhaust port)

Application: F22A1 with 16G turbo, Also on the look out for an H23 intake manifold to go with this head and Bisi's turbo cam.

[fatboy1185]

I'm pretty sure port matching is just making sure both openings are the same size. like if you had a 70mm throttle body, and a 65mm intake manifold, you would want to port the intake mani out to 70mm, so it matches the throttle body

[wed3k]

exactly...however for header port matching, apparently you'd want it stepped because of the sound waves being produced and will flow back into the head. with it being stepped, it will somewhat block the waves from entering the head and these waves could possibly mess with airflow.

just a theory i heard.

[F22Turbo702]

Most people keep about an 1/8th of an inch step from the ports to the header/manifold, it helps prevent reversion of exhaust gas back into the combustion chamber. This can happen with a cam that has a lot of overlap.

Like mentioned above, when you're port matching a throttle body to an IM, you're matching the diameter of the two pieces, but when you're port matching the exhaust ports on a head, you're just matching them to each other so that they are all similar and therefore flow a similar amount.

I'm getting ready to do my own DIY port/polish. I bought the Standard Abrasives deluxe porting kit. PM me if you need any tips or advise.

-Kyle

[evil_demon_01]

Is 1/8" really necessary? Will it make a noticeable difference, between having a step and not having a step?
Basically so far I have enlarged the port openings up to the size of the exhaust header, and shaped about halfway back into the port to keep the flow as smooth as possible.
I was under the impression that the exhaust ports are best to be a smooth finish, and the intake ports slighty rough to aid turbulance? Does that sound right?

[wed3k]

not only turburlence but the pockets get filled in with the air and then the air creates a layer that the rest of the free flowing air rides on top of. virtually 0 percent friction.

[evil_demon_01]

Hmm thats interesting to know, Thanks

Btw, I'll get some more detailed pics up tommorow

[evil_demon_01]

I plan on cleaning up the casting marks on the sides of the ports and also the centre divider, But I dont think I will go into any more detail, other than the portmatching.
Anyone with experience - Does the bottom pic look OK?

OEM Exhaust Port:




Afterwards:



Port Finishing:

[wed3k]

bad angle, you want to point it at the finish...furthur down the port you didnt touch so the afterwards pic is redundent.

cleaning up the casting is pretty straight foward. it is when you really get into porting that there's a total science in it...air flow, injectors, squish area, distance from squish to back of intake valve, the finish of the divider for 4 valve/cylinder, blah, blah, blah...

[evil_demon_01]

Thanks for the help
Finishing pic added above

[wed3k]

oh, thats pretty nice. try getting some fine grit and hand sanding it the direction of how the air would flow now. so perpendicular of the sanding marks as of right now.

[evil_demon_01]

Just going to go do that now, and I'll clean up the rest of the port in the weekend
Appreciate the help