Originally Posted by Scargod
How much misalignment can you get away with?
I am not doubting you, or that there are limits, but Vibrant Performance says of their product: V-band flange assemblies feature a unique "Male/Female" design to ensure proper alignment of the flanges inside the clamp. There is also this type, where the tubing provides the alignment.
While that would not eliminate stresses due to misalignment, it would allow you to first fit it together loosely then attach header nuts to the heads and then progressively tighten the assembly. It would probably mean pulling the engine to weld the v-band flanges on in the first place or you would have to have jigged things up on an existing motor, on a stand, with turbo in place.
I want to do it, but I don't look forward to it.
It's not a huge problem if you're fabricating everything yourself.
It's just not super easy to install if you have no flex sections and all the joints are vband. Without brackets, you really need to keep all of the vband clamps slacked. The good vband flanges have an inner receiving ring that's very shallow. If you pull on one part, another will slip out and male groove won't be concentric with the female receiving groove. I would highly recommend brackets for the up pipe so that you install the up pipe and lock it in place when you go to tighten the vband. It's not like it's a nightmare or anything. It's just that the virtue of the vband is to avoid gaskets blowing out. I wouldn't say at least FWIW that it makes it a lot easier to install.
Be sure that when you fab the up pipe, you tighten the clamp down well before tacking and final welding. Make the bracket last and with the vband tightened.
I think a lot of it is because the amount of leverage that our exhaust piping has. With normal flanges on the up pipe etc..I typically thread the bolts very loose and work backwards and then tighten going in one direction. As I tighten it aligns all the subsequent joints. With vband, all of the pieces pretty much have to be in place exactly as they should be to get the clamp to go around. My current up pipe didn't have a support bracket so the whole assembly moves around as I try to place the clamp around. It was a 2 person job to hold the turbo completely still to get the clamp around. I've added brackets and a flex to the down pipe, and I can do it myself now.
Also try to avoid the habit of gunning on the vband clamps once you get it on because you want to throw the clamp against the wall. Most of the vbands use a fine thread and the impact tends to mess them up if you use the gun repeatedly. It might be good to remove with air tools, but I wouldn't pull the slack out with a gun. Trust me LOL