DLV exhaust mod recommendations

[MadZach]

Hi I have sourced a spare back box and looking to get a local fabricator in the Midlands to carry out the DLV or PE back box mod. Is it a simple case of stripping the guts out and connecting inlet to outlet with solid pipe or are perforations left in? Also please forgive my ignorance but how is it possible to weld all the way around the pipe when you can't reach the underside?
Many thanks

 

[Bumpy]

Lots of stuff about this mod on YouTube.
At least you can get an idea of what's inside the BMW back box, and what sort of mods can be done. Many replace the perforated tube with a solid pipe.
Some recommend that any mods to the pipes (outside of the back box) be made with 'reversability' back to original in mind.
Quite a few who travel down this road discover that at speed drone detract from the pleasure of the drive.
Spend some time on Youtube.

Cheers and good luck.

 

[Davz]

I wouldn't weld in solid pipe, it will just be the same as removing the back box completely and straight piping it. To have some form of silencing you will need to use perforated pipe and wrap this with stainless wire wool and then use the sound deadening material from the box. The idea behind butchering the back box is to reduce the distance travelled by the exhaust gas which will increase the sound, as a shorter route through perforated pipe will increase the noise but not excessively..unless you want it stupidly loud with drone then just straight pipe it.

 

[mr.tourette]

There is still a perforated section that remains in place before you do the link pipe so its not the same as straight piping it

 

[Davz]

I still wouldn't use solid pipe as a perforated pipe would allow sound waves to dissipate reducing drone.

 

[mr.tourette]

There's no drone on a dlv box,thats pretty well documented here on the forum, I ran one for 4 years after replacing a custom box that did drone and had no such complaints with the dlv mod , obviously perforated pipe will allow sound to dissipate but would also pretty much defeat the object of the mod

 

[Mr_Ke1th]

I cut a a section from the underside as well so I could weld all the way around....I’m not sure if some others do this and let some gasses escape into the box? Really like mine now, sounds great and no drone. Not sure where the gasses from the small perforated section escape to now though?

 

[MadZach]

Thanks for your input guys. I can't seem to find hardly any videos related to this mod on a z4 on you tube to be fair do you have any links?
Mr Ke_1th do you have any videos of yours to hear what it sounds like? Where are you based?

 

[thecremeegg]

I have a short video of mine, though only stationary.
https://www.youtube.com/watch?v=wa5OpuhMh8k

I don't get any drone and it sounds great to me - not OTT but can pop and bang on request.
If you're anywhere near Surrey/Hants I'd happily let you have a listen?

 

[lucasxdiniz]

Thanks for your input guys. I can't seem to find hardly any videos related to this mod on a z4 on you tube to be fair do you have any links?
Mr Ke_1th do you have any videos of yours to hear what it sounds like? Where are you based?

[youtube]2gXIbBFJ8os[/youtube]