header installation

[kenji]

Does anyone know if its easy to fit oneself?

thanks

[Remould]

By header, i guess you mean the Exhaust Manifold? Yeah, you can easily do that yourself.

2 bolts connect the manifold to the downpipe, undo them... Remove the heatshield (2 bolts) then remove the remaining 3 bolts. Manifold off! 

Why are you removing it? If you are swapping it with a bigger bore "performance" manifold you will need to port match it with the head to get decent results.

[kenji]

what did you mean with "to port match"?

[Remould]

I don't know the exact terminology, but basically if you are fitting a manifold with a larger bore there will be a "step" where the standard port in the head opens up to the larger diameter of the exhaust manifold. Having a step like that will cause a certain amount of turbulence in the gas flow as the gasses swirl about. You will get better power gains by port matching the head to the manifold and eliminating that effect.

When you port match something you are basically removing excess material from either the head or intake / exhaust manifold so the port on both pieces are exactly the same shape and size and you have a nice smooth transition from one to the other.

I have done this to a couple of my cars in the past and have noted an improvement, you will also get benefits doing this work to stock components as production tolerances are generally pretty poor and they never line up 100%.

I'm not an expert on this, so i hope someone with a bit more knowledge can back me up. Any comments are welcome...

[Jay]

wire brush job im guessing, nothing to complicated