Plase help!

The pipe clamp is 42mm on a 1.3, 50mm on a GT. I think the material will be 1.5mm thick, so take 3mm off for the pipe, you're down to 38/39mm or 46/47mm for the end of the middle box.

i no for sure as i measured it with digital micromiter gt external dia is 45.5mm so if you want to put a back box on to the you need an internal dia of at least 45.5mm

will measure 1.0lt exhaust tomorow if you have a 1.0lt

I need the OD of the pipe going into the Backbox on a AUU (1.05) ,

"The pipe clamp is 42mm on a 1.3"

So your sayin the OD of a 1.3 is 42mm?

Cheers guys.

yer but the clamps i used for the gt exhaust iv just fitted are 48mm

will get the outside diameter tomorow for you if thats what your after as i have a spare exhaust down the shed