FJ40 Mark/Downey Header

[gonzopancho]

Are you asking about the collector flange clamp (the articulated joint) or the slip joint between the midpipe and tailpipe?

V-bands are useful where you have mating flanges, which, by definition, allow only very low to no articulation. If the flange faces don't meet when using a V-band, you won't get a seal.

25 ft-lbs should be all you need, assuming you're asking about the collector flange.

 

[zerotreedelta]

Yes, the articulated joint. It's nice if you need articulation, but it's arguably less robust than alternative joints - trading flexibility for sealing in some regards.

Realistically, I don't need articulation there, and would wager most installing headers also don't given you're already into the world of custom exhaust...might be a nice future option to offer other joints there.

 

[zerotreedelta]

Dove back in - I think I found the culprit. The bolt was visually fine, so I suspect it was the nut, but the threads weren't meshing well and the binding causing an early/inaccurate torque. I replaced the bolt with fresh hardware, and it torqued up more as expected feel-wise. I did also add a whiff of sealant as well since it was apart and no real harm...but so far, seems quiet/snug.

 

[Fe3]

Dove back in - I think I found the culprit. The bolt was visually fine, so I suspect it was the nut, but the threads weren't meshing well and the binding causing an early/inaccurate torque. I replaced the bolt with fresh hardware, and it torqued up more as expected feel-wise. I did also add a whiff of sealant as well since it was apart and no real harm...but so far, seems quiet/snug.

That's great news.

These are stainless fasteners, so you do need to use the copper/high-temp anti-seize we provide to prevent the threads from galling.

 

[zerotreedelta]

Wasn't really a galling issue, seems like was just a defect in the hardware. Bolt is a minor piece at least, easy to replace.

Still huffing out the top of the clamp at the hinge point, so it's still not sealing somewhere in the joint. Planning to drop the clamp back off and rotate it 90* this afternoon, see if that helps fully draw things in. Theoretically, that hinge point would be the area of the least draw, and the curve shape also really doesn't pull things together. Worst case, it'll just have to come back off and get zipped closed with the tig welder.

Might be worth considering more of band with a three binding points in future iterations vs the hinged clamshell, would likely give a bit better coverage and a bit more even draw, and probably also easier to manufacture to boot.

 

[Fe3]

Wasn't really a galling issue, seems like was just a defect in the hardware. Bolt is a minor piece at least, easy to replace.

Still huffing out the top of the clamp at the hinge point, so it's still not sealing somewhere in the joint. Planning to drop the clamp back off and rotate it 90* this afternoon, see if that helps fully draw things in. Theoretically, that hinge point would be the area of the least draw, and the curve shape also really doesn't pull things together. Worst case, it'll just have to come back off and get zipped closed with the tig welder.

Might be worth considering more of band with a three binding points in future iterations vs the hinged clamshell, would likely give a bit better coverage and a bit more even draw, and probably also easier to manufacture to boot.

View attachment 3938502

Let us know how rotating the clamp works.

So far we have had great luck with the articulated joint and clamp!