What wall thickness exhaust from a turbo?

[Sturmovik]

Should the exhaust directly from the turbo be any thicker than a normal exhaust?
Is 1.6mm thick enough? Or is 2mm better?

[Rz]

1.6 is cool.

[Jason Broadhurst]

It just has to have decient welds, as it is load bearing. My dump cracked, but thats because I welded it.

[RSWEPN]

1.6 should be fine... the few dump pipes i have made have been fine...and tehy only use 1.6

[Glenno]

Make sure you use thick flanges if you can though.

[Belly_up]

It just has to have decient welds, as it is load bearing. My dump cracked, but thats because I welded it.

dump pipe shouldn't be load bearing if the exhaust system is designed properly. Nor should the exhaust manifold, particularly thin wall stainless stuff. but everyone does it...

[Jason Broadhurst]

How do you stop your exhaust/manifold bearing load then?

You can only hang the exhaust in certain spots, leaving a lot of it resting on just the manifold I thought.

[Belly_up]

if you look at any top end turbo race cars (indy, F1, LM etc, particularly the endurance stuff like lemans) the weight of the turbo is supported entirely by by bracing that is completely seperate to the manifold itself. the only purpose of the manifold is to transfer gas from the head to the turbo. the bracing is designed to allow limited movement of the turdo, to account for expansion. the dump should be followed be a flex joint, and then the first exhaust hanger should be after that, so that the weight of the exhuast system is supported by the car, and the dump pipe only supports is own weight.

Having said that, every man and his dog hangs the turbo off the manifold, and lots of people get away with it, possibly cause street cars won't consistently have as much heat in the manifold as a race car will, or possibley cause people end up changing combos so often they don't reach the fatigue life of the manifold. I think a lot of people do it 'cause the oems do it, not realising that oem manifolds are heavy cast jobbies, which are also normally quite short, keeping the weight of the turbo in close the head studs. Thick wall steampipe stuff will almost certainly be strong enough, although i don't really like the idea of making manifolds that sit the turbo further away from the ports than stock, effectively sitting the weight of the turbo on a bigger lever arm with which it can act on the head studs, and the welds where the manifold joins the head plate.

Same thing goes with dump pipes, most people seem to be lucky and get away with solid exhaust systems for the full length of the car, but it's not the way it should be done. For example, the "performance workshop" who did my exhaust has the entire exhaust system rigid, and hanging off the echaust housing of the the turbo, and thus the manifold as well. the exhaust has a single hanger back near the diff, which is required to resist torsional loads, despite never being designed for such a task. I'll be remaking the entire system myself before the car goes on the road.

As with lots of stuff performance related, just becuase most people do something that way, doesn't mean it's the right way.