Butty

iTrader: (2)

The Dremel will only tickle the headers and is best for just finishing off the inside when the bulk of the work is done.
A die grinder (air or 110v) with a carbide tool is needed first to do the job quickly.

nick

mgcvk

yeah, the "laminar boundary layer" thats what I meant.....ahem!

Welloilbeefhooked

iTrader: (3)

I use a long reach air die grinder and carbide bit. The dremel, as already stated, is good for a little bit of finishing off.

s5ooob

iTrader: (1)

I aimed not to port too deeply into the bores, so as not to open them out excessively, and ruin the gas velocity. I tried to concentrate on removing the mismatched steps between joints and creating a lead-in to each one.

I did make an attempt with the carbide cutter in a hand drill at home [wouldn't fit the Dremel]...Not a chance, would've still been there now though did use the Dremel with a flap wheel to finish as Butty says.

The finish isn't quite as smooth as it looks in the pics. I think the camera flash and some clever kitchen lighting flatters it a bit. I did actually rough them up a bit with a piece of scotch brite after the flap wheel also.

harvey

iTrader: (48)

Never seen this thread before but without compressed air and a die grinder you would be at the job for days to do it properly.
It is not the amount of material you take out of the diameter that is important and we have scrapped several sets of exchange headers that have been overported to far too big a diameter. The shape of the port is critical.
The objective is to get as far in to the header as possible and the shape of the port has to improve gas velocity while there must be no steps from one section to the other.
Just putting a bevel on the port entry will not have a big effect which is where a lot of people go wrong.
Does it work? Ask anybody that has a set of our ported headers and matched uppipe.

alcazar

iTrader: (2)

I have both, and yes, it does

prodriverules

iTrader: (52)

Harvey,have you ever ported GT spec headers,do they require or benefit from doing so or not mate?.
I meant to ask when I sent you mine for wrapping.

harvey

iTrader: (48)

Both the 2 bolt GT and 3 bolt GT2 are so well made there is no need to port.
If it is your own set you could smooth off any weld overlap at the lips but it will make no detectable difference.

prodriverules

iTrader: (52)

That's good enough for me if you say so Harvey,I'll leave them alone
Thanks mate,Ryan