Exhaust stud nut torque - two different specs

I saw this as well. The two torques refer to different exhaust systems, I think. The lower one refers to the factory exhaust system installlation. The higher one to the components of a custom exhaust installlation, or that's the way I read it. I 'felt" that the higher torque was too much for the stud.

For what it’s worth, I built a Van’s RV-12iS, and they point the builder to the Installation Manual for the torque value, so the lower value.

Thanks! I did notice the reference to non-Rotax installation requirements but with the page layout I couldn't tell whether the different torque spec was under that  heading or whether the reference was parenthetical and the torque callout was specific to all installations. 

Interesting, though, I wonder why an M8 would require different torque specs.

Thanks for your help.

Bob

I assumed because the nut is copper, thus softer material, that it justified a lower torque.

Make sure you are always looking at the most current manuals - https://www.rotax-owner.com/en/support-topmenu/engine-manuals#912-series-engines

The current rev of the IM lists a torque of 133inlbs (on P5 of Ch 78-00-00)

FYI - That nut is only copper coated.