Buffing internally?

[xxtrizz]

Ok im not sure they actually do this when they make exhaust manifolds or if it is jsut overlooked. But I was curious as if maybe the internally the steel isnt as smooth as you would have hoped it to be that you could send like a rotor rooter kinda thing in and buff out the inside so its smoother ?

[andrave]

die grinder. grind down the welds, finish them up for smooth air flow. most places don't do it on their manifolds, some do.

[xxtrizz]

hmm interesting I would definitley do this for a smoother flow as would I assume alot of other people.

[Jeff240sx]

It's called extrude honing, and it's expensive.-Jeff

[C-Kwik]

You might see a slight benefit from this on a cast manifold, and a poorly welded tubular or log manifold. But not from making it glass smooth, but from getting rid of imperfections that may exist. My Rev-hard mani was pretty smooth already, however.

[andrave]

well, as one of the magazines I was reading pointed out, those little weld "boogers" that are on the inside can come loose and enter your turbo if they are in your manifold... and there than can break stuff.