diameter of gti exhaust

anybody know the diameter of a standard gti exhaust just before the back box?? iv got a 1.1 and want to fit a gti backbox because later on im hoping to fit a 1.8 lump.
                    ta

quite a large difference actually and will also involve chopping up your centre section as the joins are in completely diferent areas underneath, you could try chopping your centre section and mating the gti back box to it with possibly a couple of sleeves fitted but itll always be a bodge

not too bothered bout chopping the 1.1 system up as im hoping to get it all in stainless when i put the 1.8 lump in. but at the mo i just need to get a new back box on it so i thought i might aswell put a gti one on.

It's 45mm OD, so probably a 42-43mm ID. I imagine it's easier to fit the centre and rear sections then bodge your manifold to them with some flexi pipe.

It's really not worth the effort if you are going to use a standard Gti box, just get the right one for the car…

thanks 4 the hlp, no its not gunna be a OEM box itl b a stainless one.thats y i might as well buy a gti one now tho so i dnt have to put another one wen i put the 16v lump in.

if you have an engine conversion planned for the near future why not just whack on a replacement 1.1 one from a regular autofactors like partco, you can probably get one for less than ?15 including vat and then just do the job in one go when you do the engine change, otherwise it sounds like one hell of a palava!
Plus according to the bible (Golf  gti performance manual - Tim Styles) and i had heard it previously from other sources if you want stainless exhaust bit you need to uprate the sloppy standard gti engine mounts otherwise cracking exhausts is very common.