i put mine on the y pipe where the two pipes meet

 

 

That location is one of the two possible places to put it, or atleast that I would recommend. That is great where it is, or you could have also put it on the rear bank headers since the rear cylinders tend to run lean first (or have more detonation problems) due to being last on the fuel rail....

 

i tend to put my either under my arm pits, in my mouth, or.....
as close to the manifold as possible