port polish???

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what is port polish and what does it do to make your car better?

posted by  silvia_star

polishes ports?

posted by  windsonian

Noooooooo. That would be too easy of an answer. :mrgreen:

posted by  Godlaus

WHAT THE HELL YOU MEAN? porting your cylinder heads?? making them smooth and can make them a little bigger for better flow.

posted by  CarEXPERT

Pretty much

posted by  99integra

A port polish is just a procedure where the intake and exhaust ports in your cylinder head are made bigger to allow more air into the combustion chamber with less resistence, and depending on the application are made smoother or made with certain grooves to help get the best performance for whatever application.

posted by  Zalight

I had it done on my Integra and it felt like it was running smoother

posted by  99integra

"Port" means to enlarge the airflow opening (porting cylinder heads typically means enlarging the intake and exhaust ports). You can also "port" exhaust manifolds, turbo manifolds, intake manifolds, turbo housings, O2 housings, etc.

"Port Polish" means to polish those surfaces you've just enlarged.

Polishing the intake port is never a good idea. Porting can be a good idea, but not in all instances.

posted by  Bino

Never polish your port as David Vizard proved that you'll lose power.

From David Vizard:


To port effectively you'll need a flow bench to see how much flow the cylinder head is making. Best done by specialist and is essential for high power outputs.

posted by  fudge

Dave Vizard is right on the money for intake ports. It is, however, beneficial to polish the exhaust ports.

posted by  Bino

True to a point, but flow benches don't indicate how well fuel is entrained.

One basic rule is to get the air flow to strike the back of the valve(s) evenly, without bias. Thus you should concentrate on the long radius, rather than the short = usually concentrate on the roof of the ports. Bowl volume also has a measurable effect.

A good way to imagine how the air will flow is to think of the air as water being forced into the port. If it hits a blank flat wall it will setup a high impedance reversion wave and also be turbulant, whereas if it hits a radius bend it will be more likely to have a laminar flow and good throughput. Keeping with the same thought a fast flow is more likely to reach the top of the piston than a slow diffuse flow, so a bigger port area with slow flow can result in less volumetric efficiency.

posted by  Wally

But on a stock engine, you dont need to port the ports right? Only when you start putting on more performance things and forced induction right?

posted by  CarEXPERT

Me and my dad are about to port and polish the intake manifold on his saab 9000T. Then we might run a direct-port nitrous system. Muahahaha SAAB FROM HELL!!!

posted by  TurboLag

It's just not worth the effort to polish any of the ports. Dyno tests has been proven that a rough finish is as good if not better than a polished finish.

posted by  fudge

Poishing actually can be beneficial....in the right areas. The air/fuel charge going into the heads really needs just a little turbulence........it helps with combustion.
Polishing is good for the combustion chambers and exhaust ports. It greatly reduces carbon deposits. Also reduces the chance of detonation(ie: spark knock, pinging...whatever you preffer to call it) when the combustion chambers are polished and the edges a broken. Sharp edges and scratches...even fine scratches..... will cause hot spots which increases the possibilty of detonation.
Sooooooo............polishing has its place......its not in the intake ports.

posted by  norice

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