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these are things said by a few members on another forum. i felt it somewhat persuading (in a good way) to anyone thinking about the service, as these are unbiased people, simply members of another forum discussing the process. there were lots more comments & none negative towards the process. emmaculate whats up with the GB!!!???
you cannot compare a hand job PnP with EH. If you truly understand how EH works then there would be no question regarding which is better and how the processes are different.
I don't care who performs the PnP job, a human cannot reach all the same areas and remove material as accurately as EH. The only reason EH might not yield gains across the entire rev band would be due to improper port matching.
The concept of distributed forces over an area (i.e pressure) being used to refine the surface and remove material from a closed passage is superb.
The surface finish that results from EH is ideal for maintaining the boundary layer and improving flow. PnP is old school and anyone that tries to suggest polishing any surface is going to improve flow performance is just living in the past.
Pick up a fluid dynamics or thermo book in the library and get informed before wasting $500 on a PnP hand job. Save your cash and do it right.
Assuming that the abrasive media is exerting equal pressure in all directions and an equivalent amount of material is removed from the entire passage, the venturi shape or relative geometrical shape should not change dramatically.
Increasing the overall cross sectional area slightly may have less of an effect on velocity than simply reaching in with a grinding tool and removing gross amounts of material where you can gain access. From what I recall when studying this in fluids class many years ago, the valve opening was actually the throat or smallest section of the venturi where fluid (air & gas mixture) velocity was supposed to be the fastest.
Assuming that the abrasive media is exerting equal pressure in all directions and an equivalent amount of material is removed from the entire passage, the venturi shape or relative geometrical shape should not change dramatically.
They inject an abrasive paste at high pressure, into (a manifold, intake runners, heads, ect) to port the entire runner. The finish is like glass, and looks like a mirror. It cuts the entire runners at the same time, with the same pressure and same abrasive. There wont be any deviation from one runner to the next.
I had a GM TPI intake ported back in the day to match my heads (called a port match). Problem with this is.. you can only go so far into the runners of the intake or the head. usually its only about 1-2" deep.. which is enough to give you gains. But the problem with the porting by hand is.. mistakes can be made.. and sometimes the port work from one runner to the other is uneven.
I sent out my intake and heads to extrude hone.. got them back.. installed.. took it to the dyno.. made an additional 15rwhp OVER the original portwork which netted me 12rwhp to begin with.
you cannot compare a hand job PnP with EH. If you truly understand how EH works then there would be no question regarding which is better and how the processes are different.
I don't care who performs the PnP job, a human cannot reach all the same areas and remove material as accurately as EH. The only reason EH might not yield gains across the entire rev band would be due to improper port matching.
The concept of distributed forces over an area (i.e pressure) being used to refine the surface and remove material from a closed passage is superb.
The surface finish that results from EH is ideal for maintaining the boundary layer and improving flow. PnP is old school and anyone that tries to suggest polishing any surface is going to improve flow performance is just living in the past.
Pick up a fluid dynamics or thermo book in the library and get informed before wasting $500 on a PnP hand job. Save your cash and do it right.
Assuming that the abrasive media is exerting equal pressure in all directions and an equivalent amount of material is removed from the entire passage, the venturi shape or relative geometrical shape should not change dramatically.
Increasing the overall cross sectional area slightly may have less of an effect on velocity than simply reaching in with a grinding tool and removing gross amounts of material where you can gain access. From what I recall when studying this in fluids class many years ago, the valve opening was actually the throat or smallest section of the venturi where fluid (air & gas mixture) velocity was supposed to be the fastest.
Assuming that the abrasive media is exerting equal pressure in all directions and an equivalent amount of material is removed from the entire passage, the venturi shape or relative geometrical shape should not change dramatically.
They inject an abrasive paste at high pressure, into (a manifold, intake runners, heads, ect) to port the entire runner. The finish is like glass, and looks like a mirror. It cuts the entire runners at the same time, with the same pressure and same abrasive. There wont be any deviation from one runner to the next.
I had a GM TPI intake ported back in the day to match my heads (called a port match). Problem with this is.. you can only go so far into the runners of the intake or the head. usually its only about 1-2" deep.. which is enough to give you gains. But the problem with the porting by hand is.. mistakes can be made.. and sometimes the port work from one runner to the other is uneven.
I sent out my intake and heads to extrude hone.. got them back.. installed.. took it to the dyno.. made an additional 15rwhp OVER the original portwork which netted me 12rwhp to begin with.