Exhaust manifold porting

[MarkB]

Anyone seen a how-to for exhaust manifold porting on the B5 S4/RS4?

I'd be interested to see some before and after pictures.

[Chubby]

Anyone seen a how-to for exhaust manifold porting on the B5 S4/RS4?

I'd be interested to see some before and after pictures.

I am in the middel of porting and polishing my RS4 heads - will try and get some pics for you.

Regards,

R.

[MarkB]

Great Thanks

[JonnyX]

Doug did mine for me. It was very easy (for me) .

[MarkB]

Doug did mine for me. It was very easy (for me) .

Yes. How much cost? Does he do them on exchange?

[s4woody]

mark there easy to do..just fix a gasket to the face of the manifold and open it out to the gasket port size..making sure you taper back into the manifold..ive done a few..

[MarkB]

The worry is that the exhaust manifold is tubular so you don't want to take away the strength. Which is why Doug TIG's then after modification.

[s4woody]

whats the worry..i TIG also..oh and MIG..oh and Gas..oh and BRAZE..oh and ARC..and ive also been known to solder..

[MarkB]

So at what point would I know I have to put some more metal back after grinding away the surface?

[s4woody]

ha ha ..when you see a hole...

So at what point would I know I have to put some more metal back after grinding away the surface?

the face of the manifold is what your gonna be opening up the most..which is quite a sturdy piece of metal..once you start to go inside the manifold then you have to be carefull and taper it ..
if you get some engineers blue and offer up a manifold to a head you will see just how much the posrt on both differ..then you work from there..as a novice of course..

[tdiquattro]

I am not so sure woody,

If you look for the previous thread where we discussed this you can see the weld is the thing that needs grinding back not the face of the manifold, it actually sits proud of the inside of the pipe.

So Mark has a very good question, how do you grind out the weld and re-fill it, but make sure the mani is still strong enough and there are no leaks. You cant see the pipework from the outside to check the weld as it is covered.

[MarkB]

Here http://rs246.com/index.php?name=PNphpBB ... c&start=15

[tdiquattro]

Pic...

[MarkB]

Seeing the pic again I'm thinking it doesn't look too bad. Obviously could be better but with the state of tune I'll be running probably safer to leave it alone.

[tdiquattro]

Yep Mark,

I'm in the same situation, just about to get the engine out and thinking about this mod, but it sounds risky as you cant inspect the weld on the outside, and with so many problems noted on the ebay manifolds with the welds isn't this introducing the same unpredictibility?
How long have the MRC moded ones been in and working for?

Also the diameter of these three exhaust port tubes are the same as the one on the turbo end of the mani so isn't that where the restriction is. Getting rid of the lip of the weld has to be a good thing but too risky I think.