Difference between porting and gas flowing

[obi_waynne]

I think there is still a lot of confusion out there between porting a head and gas flowing a head.

A lot of people seem to think that both are different terms for the same thing. Perhaps they are, is it a regional thing?

Would someone like to explain what porting and gas flowing are in simple terms to help clear up this misunderstanding?

 

[Loz]

I thought porting was the process of modifying the head & then you gas flow tested it.

 

[old-git]

You modify the cylinder head ports so the gas flow is improved.

However, I have heard both terms used to describe the mods made to a head - 'my head has been ported' and 'my head has been gas flowed'.

Many heads have had work done on the ports but few have then been put on to a gas flow meter to be checked.

 

[obi_waynne]

So are the terms related to the same thing then in your opinion OG?

Personally I see porting as just realigning the inlet and exhaust ports and doing a bit of matching on them.

I see gas flowing as relating to the whole internal head right through to the valves into the engine?

 

[stamford]

I thought the two went hand in hand as you would 'port the head to improve the gasflow?

Porting-to improve the flow of gasses on both inlet and exhaust ports by metal removal and in-turn improving the flow of gasses in and out. With porting I would expect both inlet and exhaust manifolds to have enlarged apertures and matched bore to bore then dowelled to avoid any steps.

Gas Flowing- This would be the fine tuning part of the porting I would guess, to obtain optimum flow with no flow disruption and to maybe hone the surface finish be it smoothing or rifling, which seems to be a lost art these days.

 

[old-git]

I thought the two went hand in hand as you would 'port the head to improve the gasflow?

Porting-to improve the flow of gasses on both inlet and exhaust ports by metal removal and in-turn improving the flow of gasses in and out. With porting I would expect both inlet and exhaust manifolds to have enlarged apertures and matched bore to bore then dowelled to avoid any steps.

Gas Flowing- This would be the fine tuning part of the porting I would guess, to obtain optimum flow with no flow disruption and to maybe hone the surface finish be it smoothing or rifling, which seems to be a lost art these days.

I would go with this as well.

 

[obi_waynne]

Some have explained it thus...

"Porting is the actual work that is done and gas flowing is the aim."

 

[HDi fun]

Depends how badly designed the engine was in the first place.

 

[SLEEPER]

I dont disagree with anything said so far really .

A lot is caused by the wrong use of a term (as in suspension/dampers etc)

I would say the difference for me is very similar to stamford

porting is far more radical - changing the shape and size of the head for more air flow than before

gas flowing is more polishing and matching existing ports to manifold for optimum flow without changing the maximum flow

come to think of it thats wot he pretty much said ............time for bed