Z4-forum.com

Evening all.

Long story short - I am looking for a little more volume from my stock 2006 2.5si exhaust, without excessive drone and/or popping and banging every ten seconds.

I've spoken to a chap in Warrington about doing the mod (yes, I realise who this is!) but before I drive up there to metaphorically pull the £300 trigger, I wanted some feedback from anyone that had experience of this mod.

Comments and advice welcomed - many thanks in advance!

I have had the 'DLV style mod, but done by another person known to the forum. MY suggestion is to not do it that way. It will fall apart.

By all means mod your backbox, just don't don't go their sh***y stainless steel hose way. I paid the same for proper pipe work from an exhaust shop.

I ran a DLV box for a couple of years in my previous 2.5si, which I swapped over to my current 3.0si; my son has had one on his 2.5SE for almost four years. Both of us are happy - you get enough pops on overun but not too many and the car sounds like it should under acceleration, and not like a Mondeo.
A point worth noting - you can ask him for the usual 'full-fat' version, or a slightly toned-down version. We prefer the toned-down version, though the original version is way, way better than either a small retro-fit back box or back-box delete (i inherited both of those when I bought my zeds, and had the DLV box fitted to each immediately).

I've had a DLV mod'd backbox on my Z4 since the summer of 2017, so almost six years now. Mine hasn't fallen apart. Mike fitted two new stainless pipe clamps for me 2.5 years ago, but the backbox itself is 100% fine. Great sounding, not o.t.t, no drone...I love it. Still makes me smile. I also have a couple of close forum friends that have the same DLV b/b and theirs are going strong also.
In December '21, prior to fitting my Supercharger; I had Mike remove the secondary cat internals for better gas flow and some added 'Snap, Crackle and Pop'. The almost 19 year old ceramic was in a very poor condition and, having passed two MOTs since removal; obviously wasn't doing a fat lot either !

Yea I had mine done about 4 or 5 years ago, love it. Can make it crackle nicely on demand and it's a nice volume, not too loud and doesn't drone.
I did take a crap video a while ago of some light revs when the car had sat for a year if it helps. If you're anywhere near Farnham you're welcome to hear it in person?
https://www.youtube.com/watch?v=wa5OpuhMh8k

Thank you all - great feedback so far.

thecremeegg wrote: ↑Thu Jan 19, 2023 8:57 pm If you're anywhere near Farnham you're welcome to hear it in person?

Would love to, just a little too far! Anyone in the Nottingham area?

Its a great mod..had it on both my e85 and e89..money well spent

Loved mine on my 2.5i! Could scare people with it by making it pop and bang on demand Only issue I had was the clamps to the rest of the pipes gave up after a while - easy to replace though.

groovy_hippy wrote: ↑Fri Jan 20, 2023 3:58 pm Only issue I had was the clamps to the rest of the pipes gave up after a while - easy to replace though.

He now uses some upgraded clamps that are better

Sidewaze Samm wrote: ↑Thu Jan 19, 2023 8:41 pm A point worth noting - you can ask him for the usual 'full-fat' version, or a slightly toned-down version.

This is very interesting and not something that I was aware of. My gut says that I'd also want the toned-down version.

What did most people choose that have the mod - full fat?

jumeeno wrote: ↑Sun Jan 22, 2023 10:13 am

Sidewaze Samm wrote: ↑Thu Jan 19, 2023 8:41 pm A point worth noting - you can ask him for the usual 'full-fat' version, or a slightly toned-down version.

This is very interesting and not something that I was aware of. My gut says that I'd also want the toned-down version.

What did most people choose that have the mod - full fat?

I'd say that the vast majority have the "full-fat" version, simply because that's the default unless you ask otherwise.
My son had one on his 2.5SE, then I bought a 2.5si and fancied one too. But I thought it was a little too loud for urban driving, so simply asked for the mod to be a bit more "semi-skimmed" than "full-fat". After a while, my lad agreed with me and swapped his over to match mine. (The advantage of being relatively local!)

patriot66 wrote: ↑Thu Jan 19, 2023 8:43 pm I had Mike remove the secondary cat internals for better gas flow and some added 'Snap, Crackle and Pop'

Got to agree, that's certainly worth doing. My lad's 2.5 has it viewtopic.php?t=129420&hilit=cat but I can't do it on mine
None to remove on the Si models...

Hi mate ,i have one fitted it sounds great pops back on overun louder when you hoof it but it doesnt drone on motorway .i would recommend it

Sidewaze Samm wrote: ↑Mon Jan 23, 2023 3:21 pm I'd say that the vast majority have the "full-fat" version, simply because that's the default unless you ask otherwise.
My son had one on his 2.5SE, then I bought a 2.5si and fancied one too. But I thought it was a little too loud for urban driving, so simply asked for the mod to be a bit more "semi-skimmed" than "full-fat". After a while, my lad agreed with me and swapped his over to match mine. (The advantage of being relatively local!)

Do you know what the internal differences are between the semi-skimmed and full fat versions are? On the pics I've seen, there are 2 pipes going through the silencer to the tail pipes, does the semi-skimmed just have one pipe, with the other standard, still using the silencer?

.adam. wrote: ↑Thu Jan 26, 2023 4:42 pm

Sidewaze Samm wrote: ↑Mon Jan 23, 2023 3:21 pm I'd say that the vast majority have the "full-fat" version, simply because that's the default unless you ask otherwise.
My son had one on his 2.5SE, then I bought a 2.5si and fancied one too. But I thought it was a little too loud for urban driving, so simply asked for the mod to be a bit more "semi-skimmed" than "full-fat". After a while, my lad agreed with me and swapped his over to match mine. (The advantage of being relatively local!)

Do you know what the internal differences are between the semi-skimmed and full fat versions are? On the pics I've seen, there are 2 pipes going through the silencer to the tail pipes, does the semi-skimmed just have one pipe, with the other standard, still using the silencer?

No idea at all but I guess it must be something like that