am looking at having a spare manifold i have gas flowed after its welded up, but going to have a go myself as a learning experience... current manifold on the car is cracked.

1 - has anybody done this and give me any tips ?
2 - what is best tool to do this... small file or dremmel type tool ?
3 - anybody who has done this... what effect did you see, more power / better spool up ?
4 - will i need to do anything else after doing this before fitting to my car ?

anything else i should know before doing this ?

I have one that's already been ported if you want it. It was done by Motormech so assume it was done right.

However it doesn't sit flat on a flat table so I guess it needs to be skimmed. From memory there's about a 2mm difference from one side to the other.

Oh, and to answer the question you want to get it as smooth as you can, polished even.
I didn't see much of an effect after having it fitted.
You can just fit it, no other supporting mods required.

thanks for the offer of yours.... but no thank you.

am after doing mine as a winter indoor project for something to pass the dark nights and something i can learn.

Buy the exhaust gasket and lay it over the primaries of the manifold, you will see the amount of material you can remove from each primary port.

I wouldn't go for a polished finish, just make it nice and smooth and remove any lumps and bumps. Airflow through a tube, the faster air will try to be in the centre of the tube if it is straight, more complicated if there is a bend, the velocity on the inside of the bend will be greater than the outside so the outside path should be nice and neat to try and keep flow as symmetrical as possible.

Sounds like a fun project, enjoy it. I would certainly use a dremmel over a set of files.

You'll be there for months with a file - get a Dremel and some high-quality bits

If you take a look at the face of the exhaust manifold, you'll see soot marks where the manifold ports are smaller than the ports in the head - what you're looking to do is open up the manifold so that it matches the head, with no step from one to the other

Make sure that its a very gradual tapering - you don't want a rapid reduction on the port size, as it will cause turbulence in the gas flow

Thank you for the tips. I will have to get myself a decent dremel for the job. i have a gasket on order and on the way, will have to use chalk or something to mark the bit to be removed as i have cleaned the manifold and removed al the original carbon.

Here's one I did for a build last year. I use a tapered tungsten carbide bit and finish with a selection of different grit stones.
The exhaust manifold gasket is pretty much bang on to the head ports so use that as your template lines along with engineering blue ink of sharpie pen.
It's time consuming so make sure you're comfy with a good light.

at the risk of asking a silly question... is it just the 5 ports i do, or should i also be doing the turbo port / flange ?

I feather the edges of the castings as they come together inside the collector and match the flanges to the turbo which might mean porting the turbo itself if you follow.

I bought a ported exhaust manifold from Joe (Countrycruising) last year, more than happy with it

picked up the manifold from local company, fitted the two gaskets and gave them a shot of paint to mark the bits to grind away. removed the gasket then wiped off the wet paint on gasket only to slice the end of my finger very deeply.... so now the manifold has designer blood stains on it too lol.

so after i have done the manifold, i will have to open up the face of turbo as well to match them best as possible.

when i get to the point of grinding them down... what the best method. do i do it about an inch in with a constant lead to the original size at the end of the inch ?

do i make is smooth as possible or is there some pattern i need to create on the found parts. ?

Can you post some pictures once you are done please?

i would, but no idea how to do it on here... for me a computer has an on of button and cut n paste lol...

but i can put it on my Facebook page as i know how to do that.

finally got round to gas flowing my spare manifold... so next year i will be asking flea to check i did it right and fit it for me

Good work and I'd be interested in the photos!

Here's a how to guide on posting photos.

have had a go at this photo bucket thing...

link for photos if it works...

http://i1050.photobucket.com/albums/s405/go_fast_chris/imagejpg1_zps5067dd22.jpg