AU XR8 headers - Ford Forums

JC-XR8 · 06-30-2004, 21:21

I've posted this in the DM section as well, but thought others who are not DMs might also have some relevant info/opinions etc.

I was talking to another car enthusiast yesterday about my XR8. He has a mate who owns an AU2 XR8, and instead of fitting aftermarket headers, he took a die grinder to the standard factory ones and cleaned up the ports. Apparently, the standard headers have a lot of welding on the inside of the header pipes (where they join the manifold which bolts to the head). Flattening out the weld "lumps" apparently increase air flow through the headers and is worth up to 5rwkw.

What I want to know is has anyone done this - if so, did you notice a difference.

Can anyone who is mechanically-minded tell me if this is worth doing - I would have thought that die grinding the welds would weaken the headers.

Thanks guys - I know this sounds like a bit of a stupid question, but if it works, it is free horsepower and I won't bother with extractors (can't afford them anyway).

galaxy xr8 · 07-01-2004, 03:59

Yes well I have a set of these header's at home and I've looked at them before and thought they wern't a bad design overall, you can see the weld spur's but I don't know about smoothing them out, you should be able to without weakening the surface.

xdv8 · 07-03-2004, 17:51

ihave an ua 1 v8 & mine were perfect the best id ever seen, i changed the whole exh

xdv8 · 07-03-2004, 17:55

i only got 12.5 kw at the wheels extra & after rooting around with systems over the years & dyno testing every thing i would say 5kw is a bit much to expect from cleaning up some weld flashing without changing anything, but dyno it, do it & dyno it again & see what you get!