Porting and polishing allows combustion air to flow more freely through the head and therefore make more power. It is widely accepted that when measured on a flow bench that the higher the volume flow rate for a given pressure differential(or the lower the air pressure to create a particular flow rate) the better the port job, and therefore the more power potential. I’ve seen owners post up about buying one particular ported head over another because of the flow numbers. This could very well be a mistake, because as any good porter should know they could end up making it flow too well.

What I mean is that you want certain amount of turbulence and mixing of the intake air to promote the fuel and to a uniformly mixed vapor. In our trucks for example we would want the air to flow as smoothly as possible through the intake, through the blower and past the intercooler with as little turbulence as possible to get as much air in there as you can. But at the point where the fuel is injected you want to promote some turbulence all the way to the combustion chamber and inside the combustion chamber as well to maximize the burn and efficiency. Afterward for the exhaust you want it to be like the intake again and flow as smoothly and freely as possible. Obviously you don’t want too much turbulence that would end up causing a lot of pressure drop and would reduce the overall air flow and power created by the port job. But it needs to be there.

One method: Some porters who are familiar with concept this will polish the exhaust as smooth as possible while leaving the intake side at a slightly rougher surface to promote micro currents that will swirl the air fuel mixture as it travels into the combustion chamber.

I would like the pose the question to the porters and the vendors who sell ported and polished heads, What are you doing to maximize air fuel mixing in the design of your port and polish jobs?

 

You would want to actually talk to the people building the engines. Not the people just selling them.

VT
Fox Lake

 

like you said I primarly mean the builders(porters), but I mentioned vendors because some claim to engineer their own products and have it built, and have their "spec" or twist on the products they sell. The ones that do that have the added responsibility of supporting their designs and the principles behind them.

 

I could be wrong...but I was under the impression that the turbulence theory applied mostly to carburated engines so you don't drop the air/fuel mixture out of suspension. With the ultra fine atomization of of modern fuel injection, turbulance becomes less important. On the other hand, some diesel engines use turbulance chambers, or swirl chambers, or power ports, or what ever you want to call them, to create this same effect. But that may be old school technology. In other words, I haven't helped you at all! Sorry dude!

 

Good luck getting that info.