Downpipe Fabrication

[DomF1]

Hi all,

I'm starting to get together all the pieces in order to make a 3" exhaust from the turbo back. I've sourced a 16t and the d/p flange so will be welding the flange onto the 3" pipe - seemed the only way to get it all together.

With regards to the downpipe, this is where I'm searching for some advice - would two 90 degree bends work? Does there need to be an angle created at the turbo flange or can you squeeze it in past the chassis going straight out of the turbo and down?

Flexi joint wise I was going to add this at the bottom of the downpipe, is this best or is in-between the two 90 degrees better? Its then going to go into a Y piece, one exit nice and quiet the other will have a QTP valve into a side exit. I want to have two options I don't want to drone along all the time...

Any ideas or examples would be greatly appreciated!

[crogthomas]

Remember that the standard downpipe has a bracket tying it to the bellhousing halfway down the vertical section. That would be a very good thing to replicate in my opinion. This of course means you'll want the flexible section after that. So after the second 90 seems a good place, and is where most vehicles seem to put it anyway.

[DomF1]

Thanks, ill remember to fab something up to replicate that.

So would two 90 degrees work or am i going to need to do more?

[Ml 1990 740 turbo]

Two 90's works fine. U may need a little straight piece between the two. U can't get away with it coming straight out and down or it'll clash with the steering column. To do it properly u will need a 2.5 to 3 inch reducer cone thing. U can get them on ebay. Then cut a little cheese wedge to give u a angle. It is very tight between the column and engine. But if u get it centred it's fine. I put a flexy pipe at the bottom of the downpipe after the second 90. Works great. If u pm me your email or number if ur on whattsapp. I'll send u some photos

[DomF1]

Thanks for that. I was hoping you would reply after seeing your build! ill pm you