[baconbits]

I know everyone says bigger as better and most downpipe makers will agree, which is why we have 3.5" and 4" downpipes for the PWG and EWG cars.

I work for a domestic exhaust manufacturer and have some prototype V-band flanges left over from an abandoned F10 M5 downpipe project. I'm hoping the flange size is the same or very similar because I was given the "go ahead" for some government work where I would be able to build my own downpipe (F10 535i xdrive) from this virtually scrap flange, scrap tubing, and a couple O2 bungs I'd have to buy.

That said, scrap 3" is all over the place because that's 75% of what we bend. Back in my VW and Subaru days, 3" could support around 500 wheel before it became a restriction. I can find some 3.5" but we don't run that diameter very often so scrap is scarce.

Could I get 3" to work on the stock turbo? What's the inlet diameter for our catback? I'm pretty sure it's larger than 3" but not sure if it's 3.5" or what.

PS - If anyone has their stock PWG downpipe (2012 here) they can measure for me, can you give me a couple basic dimensions of the turbo flange? Max OD, smaller "gasket" boss OD, ID of the flow path, OD of the catback slip fit part...

[etnsandman]

I have mine on the shelf and can take some measurements tonight.