Using flex tubing instead of rigid steel pipe for exhaust?

Hi everyone, I'm on my 3rd turbo manifold (because I like pain? anyway, doesn't matter) and was wondering if anyone had some thoughts on this because I couldn't find much online. I'm basically thinking of using it for the journey on my 3.4L behind the engine (where the original exhaust ran) and upwards from the passenger side exhaust up to an X-pipe where my wastegate will be.


What could the possible downsides from using this to get from the headers to the said x-pipe, be aside from not rigidly securing the turbo to the engine? I would be welding these close to the manifold flanges.

The alternative is buying new mandrel bent 1.75" tubing and cutting it into sections to try to navigate the ideal path (again). I feel like flex tubing would offset any flow interruption by being consistent, potentially broader radii curves.


PS: I've been using 3" downpipe flex sections of the same type for a couple years. Naturally the galvanized ones rust and seize, but I plan on also ceramic coating them. They also make aluminized versions in bulk, which is what I've been mainly always using for the welded portions.

https://www.oreillyauto.com/detail/c/nickson/nickson-1-3-4-inch-flex-tubing/nic0/46972

 

Here's a drawing to help. Red = rigid; blue = what I'm considering flex for

 

I’ve used SS flex pipe on exhaust systems. They didn’t last. Maybe they make aerospace conduit. YMMV

 

Cracked, or?

 

It leaked. It was run over the rear axle to the muffler. It flexed a lot and the joints started to open up. It lasted a long year, which is good for any exhaust patch I’ve done.

I had a muffler hanging off one end bouncing up and down. Your application looks more static.

 

Custom is possible, and x-pipe will not be flex, only up-to.
The reason I really don't want to if flex is good enough is because of how much a pain it is to work in that area, take measurements, push in pull out tack welded pipe sections, etc, and I'm buying new pipe either way.

 

If you only drive the truck a few miles a year It might last long enough.

Did the Quality of the flex tube improve ?? your the person doing the job it always comes back to you .

It would not be the first time a firewall has been massaged or moved .

Best of Luck !

 

That's the thing, there's really not much info on it out there. All I'm gathering thus far is that it's prone to leaking over time if it's under constant movement, which tracks logically.
The side option is to use it for the wastegate dump tube - and I've seen that advertised by Vibrant. But is that because everything around it is rigid and not failure prone? Is it because replacement when it does fail is presumed to be easy? Not sure.