ported and polished headers
26 August 2006, 06:56 PM
#1
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ported and polished headers
i understand how to port my original headers but i dont quite understand the term "ported and POLISHED" can someone explain to a thicko please
27 August 2006, 04:30 PM
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usually thats used in the heads, polishing the surfaces of the heads to smooth the airflow out i guess....
dont think you can polish your "headers"
dont think you can polish your "headers"
27 August 2006, 04:36 PM
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Before
After
The exhaust ports are missed matched to the headers, you need to remove all the metal out to the soot mark, and also split them and do the same with the joints etc. you don't need to polish just grind out the ports to match gasket.
After
The exhaust ports are missed matched to the headers, you need to remove all the metal out to the soot mark, and also split them and do the same with the joints etc. you don't need to polish just grind out the ports to match gasket.
Last edited by T5OLF; 27 August 2006 at 04:57 PM.
09 November 2006, 09:58 PM
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You can port them which most people do, like the pictures show but you can also polish them too for a much smoother surface then just a port, this aids further in gas flow and reduces the chance of carbon build up. I've just done my heads this way 
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10 November 2006, 12:25 PM
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Hmm, well the short one on the LH bank i can get all the way through with the right tools, the collector on the other side i just do down to the bend.
10 November 2006, 02:10 PM
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Bob, I know where you're going with this
..!
Strictly speaking gas flowing is probably more accurate a description. Basically all your trying to achieve with the cast oem headers is to reduce any restrictions in the direction the gas flow (ie hitting a big step at a joint). Actually making the bores bigger will slow the gas flow down and reduce low down response (as well as weakening the design).
One thing that needs to be done is ensuring that the gaskets are in the correct position on replacement as they can move and partially block flow. IIRC someone in projects got around this by 'tacking the gaskets in place with some gasket paste before reassembly..?
..!Strictly speaking gas flowing is probably more accurate a description. Basically all your trying to achieve with the cast oem headers is to reduce any restrictions in the direction the gas flow (ie hitting a big step at a joint). Actually making the bores bigger will slow the gas flow down and reduce low down response (as well as weakening the design).
One thing that needs to be done is ensuring that the gaskets are in the correct position on replacement as they can move and partially block flow. IIRC someone in projects got around this by 'tacking the gaskets in place with some gasket paste before reassembly..?
11 November 2006, 03:03 PM
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Originally Posted by harvey
The porting also has to be done in such a way that the exhaust gases are accelerated.
11 November 2006, 06:03 PM
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dont want to put a spanner in the works guys, but make sure 100% that you have cleaned your headers thouroughly, any swarf left in there will end up wearing the turbo extreemly quickly!
11 November 2006, 06:24 PM
#19
Originally Posted by harvey
The porting also has to be done in such a way that the exhaust gases are accelerated.
http://i16.photobucket.com/albums/b4...n/100_0682.jpg
11 November 2006, 06:28 PM
#20
Originally Posted by wez wrx
rentone
they look good! did you use a rotary file for that? thinking of doing mine but still have cat downpipe. would there be any noticable gain??
they look good! did you use a rotary file for that? thinking of doing mine but still have cat downpipe. would there be any noticable gain??
11 November 2006, 07:26 PM
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Originally Posted by M555JHE
dont want to put a spanner in the works guys, but make sure 100% that you have cleaned your headers thouroughly, any swarf left in there will end up wearing the turbo extreemly quickly!
11 November 2006, 10:04 PM
#22
I am not sure that a highly polished surface is desirable or necessary.
Because of the arduous nature of the work involved, removing quite a lot of cast steel, I find powerful air tools are essential. As is a variety of tools to get as far in as possible and reach otherwise inaccessible areas.
A flexidrive is essential.
Because of the arduous nature of the work involved, removing quite a lot of cast steel, I find powerful air tools are essential. As is a variety of tools to get as far in as possible and reach otherwise inaccessible areas.
A flexidrive is essential.
11 November 2006, 11:06 PM
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I read in one porting and polishing guide that the inlets should be left slightly rough/course to the touch and the exhausts should be polished as much as poss, to stop carbon build up i presume..
12 November 2006, 10:50 AM
#24
Originally Posted by BOB'5
Not going anywhere with this.
Was just curious how far down the headers people were able to port.
Was just curious how far down the headers people were able to port.
Its all finished off with a grinding cone down to 200 grit.
I can't even contemplate polishing the things up, the time spent would be far longer than doing the useful part of porting.
Oh and don't do it near a car
12 November 2006, 03:07 PM
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The worst bit IMO is removing the original brackets for the heat sheilds, a real PITA and made more mess than all the porting..!
Obvioulsly you don't need to do this but it makes wrapping a fair bit easier..!
Obvioulsly you don't need to do this but it makes wrapping a fair bit easier..!
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