on the si/itr JR manifolds, there is that little brass plug for water injection. does anyone know what kind of thread/what size thread is used on this plug? i cant seem to find any fittings at my hardware store or home depot that will thread in there. the threads on the plug are too fine for anything in stores. i found some online sites that might have finer threads, but the problem is i cant hold it up to the plug to guage the size. i'm not experienced in reading thread sizes, so can anyone lend a hand?

 

It is a very fine thread, I believe it is 8mm x 0.75mm. Call Jackson for the plug.
1 888 888 4079.

 

i've decided to use the threaded hole where the pressure sensor normally resides, since i wont be using it anyways, and since its a more standard thread.