how do you make smooth transition from collector to round pipe?
 

I have schedule 40 manifold which I remade with 316. I have a quick question. How do I make a smooth transition from the 3 joined pipes into a round pipe? The shapes are little different. Schedule 40 is too thick to hammer form into any shape... or is it? I could grind out the inner diameter but before I do that I wanted to ask for what people usually do in this situation... I don't want to get a new collector because I don't want to remake the primary runners.

any suggestion is much appreciated. Thanks!

i put sch 10 in a vice and make it more oval to match half a t4 divided flange. i think 10 is thicker?

nah schedule 40 is much thicker. almost 1/4" in thickness.

i think you have 10. if its 1/4 inch.. this aint pvc

Heat it prior to forming, you'll find it much easier.
Just re shape the end of the new piece you are adding on.

Heat it up locally as hot as possible and smack it with a bfh and a cold chisel.

Or use a reducer cone, fill and grind.

lol tried chisel with 4lb hammer but it almost broke my hand instead. Tried to press it with harbor freight press on lead shot but it kept on slipping...

sooo, I used my tig welder to fill and smooth the inner contour of the collector through the wastegate hole. worked out pretty well actually.