Sound Generator Modification

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Bing
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Re: Sound Generator Modification

Post by Bing » Sun Jan 13, 2013 7:54 pm

Promised some photos, so here they are... Sorry it has taken me so long :oops:

Note that this is for the N52 engine - so facelift, and mine is a 3.0 which already has the sound generator installed. The M54 sound generator is different ; I do not know if a facelift sound gen will fit into a pre-facelift car. ///Ms do not have a sound generator - arguably the engine itself and the two extra exhausts do that job :D

All this will do is show you how to find the right bits in the engine to remove the foam. It is NOT necessary to take the whole sound generator assembly out as the initial how-to on this thread indicates, only the ends of the pipe that contains the foam.

This is the sound generator. The large rectangle shows the main body of the part, the second smaller rectangle shows the bit we are interested in, which connects to the firewall bulkhead :

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Close up pic from the same angle :

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Close up pic from a different angle looking from the front of the car, bulkhead connection circled :

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First stage of this mod is to simply pull the bulkhead end away from the firewall. Takes some force but just pulls out. Then twist the tube up towards you and you see this :

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The foam will be clearly visible in the hole that is circled. Mine is, of course, not present :evil:

The circled bit is important - it is rigid plastic and must be "clipped" back into the metal hole in the firewall. I use quotation marks because there is no set position, just line it up feeling with your fingers and push till you hear it click in. This is the hole in the firewall :

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If you want more noise, you need to take the foam out the other end near the engine - this is stage two of this mod. You need to undo the jubilee clip to the right of my finger below (circled in pic 2 above) - quite a long way - and work the tube off. This takes some effort and can result in skinned knuckles.

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Your choice whether you remove it completely, cut it down, or not at all. I have cut about 1/3 of it off and then stuck it back in and that's just fine for me. All foam out made my ears bleed and (to my brain) soundedlike I was murdering the engine at 6-7,000 RPM.

Getting this tube back on can be a bit of a PITA - there is a notch in the end of the tube you need to line up with a corresponding 'bump' on the fitting that is attached to the rest of the sound generator. Takes some wiggling and some force too - more skinned knuckles potentially, but worth it. Sorry, no pics of that as I was short on time - but you'll figure it out :wink:

I thought about re-posting the OP's text and my pics, but I wouldn't do it that way, and I didn't have time to take the whole assembly off. Hopefully that helps anyone else looking at this thread now the original photos are gone.
Last edited by Bing on Thu Feb 07, 2013 11:50 pm, edited 1 time in total.
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Re: Sound Generator Modification

Post by Don Gilham » Sun Jan 13, 2013 8:08 pm

Good set of pictures Bing - did mine this afternoon in a couple of mins.

The filter was grey foam, not black like some.
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Re: Sound Generator Modification

Post by Bing » Sun Jan 13, 2013 8:35 pm

My bulkhead one is grey, the one nearest the engine was black and somewhat denser-feeling. It is a great wee free mod :thumbsup:
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Re: Sound Generator Modification

Post by Don Gilham » Sun Jan 13, 2013 9:04 pm

Having read previous posts when I took it out of my first Z4, I only took out the bulkhead foam :)
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Re: Sound Generator Modification

Post by Charri42 » Thu Jan 17, 2013 5:25 pm

Great thread and thanks to all the contributors - lots of fun trying the different options, settled for removing the small bulkhead bit.

Both bits out reminded me of my s2000 with a carbon induction kit - my god it was loud!!

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Re: Sound Generator Modification

Post by Beetlegav » Fri Feb 01, 2013 2:04 pm

Just done mine. Didnt really hear much of a click when putting it in, feels more like its just sat there?
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Re: Sound Generator Modification

Post by Bing » Fri Feb 01, 2013 2:12 pm

Beetlegav wrote:Just done mine. Didnt really hear much of a click when putting it in, feels more like its just sat there?
It doesn't feel like it's in, you're right. But try wiggling it from side to side - if it moves then it's not in right.
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Re: Sound Generator Modification

Post by Beetlegav » Sat Feb 02, 2013 10:11 am

Yeah don't think it was in properly yesterday. Booted it Down the slip road and my ears nearly burst.

Shoved it abit harder and it's not as drastic.

Cheers :thumbsup:
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Re: Sound Generator Modification

Post by NeilP » Tue Feb 05, 2013 5:06 pm

Pictures are excellent.

very easy to do. though I guess I was expecting more.

shall have to take the other one out and experiment!

:D

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Re: Sound Generator Modification

Post by Bing » Tue Feb 05, 2013 5:23 pm

NeilP, somewhere between 1.5 and 3.5k RPM is the real sonorous sweet spot I find. I took both bits out, hated it. Stuck the bulkhead side back in, not enough noise. Removed bulkhead, cut 1/3 off the engine side. Now pretty perfect. Makes my ears shudder with pleasure every time I boot it :D
Last edited by Bing on Sat Jan 11, 2014 10:34 pm, edited 1 time in total.
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Re: Sound Generator Modification

Post by NeilP » Thu Feb 07, 2013 7:57 pm

Ahh that wil be why.

Changing a little too soon.

:lol:

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Re: Sound Generator Modification

Post by Bing » Thu Feb 07, 2013 11:45 pm

Yo mean you don't red line it ? :D 7k RPM is raucous, though an ///M driver will be along soon to tell me I need another 1,000 RPM :roll:
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Re: Sound Generator Modification

Post by tommycupra » Thu Feb 07, 2013 11:46 pm

this will defo be my first mod :)

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Re: Sound Generator Modification

Post by R7VOX » Mon Feb 11, 2013 12:48 am

EdButler wrote:Has anyone else got a buzzing/rattling noise coming from the diaphragm spring within the Sound Gen? It happens on mine at partial throlle, sub-2k rpm... Really does my nut! I thought it was just becuase i took all the foam out (big grins!) but still happens with the small one.

Might have to try a post-facelift one instead :thumbsdown:
Hi, I hope not to tread on anyones toes here with the mods.

As the gentleman describes above, I too encountered a rattle at low speeds or just brishing the throttle with my little toe which totally ruined the whole fun of driving with both bungs out. I did find a solution to this by taking the whole assembly down to parts and attatching a cable tie right next to where it hooks into the lower part of the spring housing inside the unit itself. This straightens the spring and stops it from rattling on itself. This seemed to do the trick. I hope it is of help to othere members that found this little issue.

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Re: Sound Generator Modification

Post by TommyGG » Tue Feb 26, 2013 12:09 pm

Had a bit of a read of this thread, and had a look in my engine bay. I have a 2003 2.5i, but I can't see the tube which holds the foam! Does my car definitely have a sound generator? There looks like there's a plug where the pipe should be, but it's sealed off.
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