(LONG POST ALERT!!!)
I've managed to get my hands on a working 2nd hand DPF for less than a Miltek or Custom pipe so it looks like the gutting option is the way forward (BTW if anyone wants to swap there knackered DPF for this working one + a bit of cash my way, shout now before I destroy it!). Now Ive seen plenty of discussions on cutting the case open, removing the honeycomb, & welding it back up, however from my experiences of fitting exhausts to other cars this has left me wondering about a couple of things...
By removing the internal honeycomb it will in effect be creating an unbaffled muffler which tend to create annoying resonances or exhaust droning (in my experiances at least) that I really dont want. I'm aware that the turbo itself massively reduces the exhaust noise/drone, but this still strikes me as being potential issue & not one that I want to experience after the b*ll ache of removing the old & fitting the new one. Has anyone any experience of the noise difference before & after gutting the DPF, how noticeable is it?
Secondly by removing the DPF internals its going to affect the exhaust back pressure massively. We all know that the DPF creates far too much back pressure, but surely having none at all (especially so close to the turbo outlet) is not a good thing either?
After rooting around on the web I've found lots of discussions where people have removed there DPF & literally smashed or drilled out the honeycomb between the inlet & outlet pipe (which I know isnt possible on this DPF), which takes care of the potential resonance & back pressure issues - A bit like running a Miltek pipe but with stock DPF appearance. Has any one tried cutting the internal of the DPF so that it creates a channel from the inlet to the outlet or welding a pipe internally rather than just completely gutting it?