In that photo the tensioner is both misaligned and also I'm using a belt that is a few inches too long, making the arm rest at almost full extension.
It was just a mock-up, though.
I have since raised the tensioner higher to allow more room in that area for the accessories.
a lot of it's currently mounted on plywood until i finalize things a bit more.
The tensioner's mounting hub has several locating holes to choose from with varying offset, with the goal being that I should be able to swap smaller/larger supercharger pulleys for more/less boost and then "clock" the tensioner to compensate. This way I won't need a different length belt for each pulley.
