Sound generator mod done - loving it!!

GreyZed said:
STUBOY2UK said:
I think it sounds awful with the foam removed, not a nice sound at all on full acceleration :cry:
Agree - just not a noise becoming of a 6 cylinder 3 litre engine at all. Sounds more like a 1 litre Corsa screeching at the limit in 1st gear. All treble no bass.
That description is spot on, you've put it better than I could have :thumbsup:

The sound is the only thing that has disappointed me with Z4 ownership, it just doesn't sound sporty enough.
 
Paulj100 said:
Put my foam back in after a week disliked the sound :thumbsdown: looking at a way to get a better sound from the back box.



Paul

remove resonators or do 2nd cat delete I have back box delete can be abit to loud at times theres a video of a guy who had same as me with drone at 70mph he refitted the rear box and removed the 2nd pair of cats no more drone just pure rasp sounds good check the video on youtube
 
Save your money, it's really not worth it! To call it a 'sound generator' is a misnomer imo, it paints a picture of something which gives a lovely deep, sporty sound which is absolutely not what the sound generator does.

It's basically just sound-proofing that, when removed, lets in a deafening (when accelerating hard) amount of engine noise.
 
my first 3 litre had the foam removed before I bought it so I didnt think much of it although I wasn't a huge fan of the noise on revving hard. It only after buying the 3.0si which still has everything in tact that I discovered how much nicer it is with it in place. A hell of a lot more of a refined noise in the cabin.
 
Resurrecting....

What’s the part number for the foam ? 😀 both have been removed on my purchase and would like to add one back. I assume cabin one easiest...
 
M340 said:
Resurrecting....

What’s the part number for the foam ? 😀 both have been removed on my purchase and would like to add one back. I assume cabin one easiest...

Here's a link to the sound generator but it doesn't show the foams. Not sure if they come with the number 6 pipe or not.

https://www.realoem.com/bmw/enUS/showparts?id=BT52-EUR-04-2003-E85-BMW-Z4_30i&diagId=13_0999
 
Thank you for this, just found it also. Looks like foam is included for the princely some of £40 😀

https://www.ebay.co.uk/itm/Genuine-Sound-Conducting-Medium-BMW-Z4-E85-Z4-3-0i-Convertible-13747514864-/264695431105?_trksid=p2349624.m46890.l49292
 
M340 said:
Thank you for this, just found it also. Looks like foam is included for the princely some of £40 😀

https://www.ebay.co.uk/itm/Genuine-Sound-Conducting-Medium-BMW-Z4-E85-Z4-3-0i-Convertible-13747514864-/264695431105?_trksid=p2349624.m46890.l49292

You could try anything really, an old sponge/ear wax etc etc :P
Rob
 
STUBOY2UK said:
Save your money, it's really not worth it! To call it a 'sound generator' is a misnomer imo, it paints a picture of something which gives a lovely deep, sporty sound which is absolutely not what the sound generator does.

It's basically just sound-proofing that, when removed, lets in a deafening (when accelerating hard) amount of engine noise.

It does generate harmonics. That’s the main purpose of it. An inline six doesn’t produce that complex a sound on its own.

It’s a similar idea to the fake cross-plane crank warble piped into a Golf R / GTI to make the four banger sound a bit more characterful.
 
With both pieces removed it is a 'hard' engine + intake sound direct into the cabin. With just the engine side removed it is far less harsh. For those that don't like the sound (I'm assuming as it is directly into the cabin) there is a 3rd way!
Bare with me...Firstly, you're better off getting hold of a another generator pipe (incase you still do not like it) and you cut it, first at the cabin end and leave enough to still have the foam that side and then fit a blank on the cut end. The engine side, cut an inch of the OE foam and then with some very tight gauze form a 'tube' over it.
Now, when I did this back in 2010 on my E85 I was throwing some stuff out and there was a kids plastic trombone....I cut the end off, sprayed it with black enamel and it was the perfect fit with the foam and gauze into the engine side and also looked like it was supposed to be! The effect was that the sound comes from under the bonnet and only when you 'get on it' and nothing like the effect of the general mod. An afterthought at the time was to cut the engine side an inch or so after the concertina section so you could point it where you want. Sadly I don't have any pictures as I begrudgingly had to sell that car, the guy who bought it loved the noise too though. A month ago I bought a 2009 E86 in midnight blue and am currently looking for 'something' that will fit perfectly into the engine side of that pipe, :D
 
It does sound hilariously ridiculous but despite the 'bodge engineering' if you didnt know exactly what it was it looked just like an intake trumpet just that it was located where you wouldnt expect to see one :rofl:
 
i removed just the engine side foam (or rather, a mate removed it for me) and left the cabin side foam in place. personally i was a fan - doing trackdays, it meant i could have a lot more noise inside the car, but no more noise outside the car, so good for drive by. Only time it got annoying was along the long, uphill straight at Spa Francorchamps... engine screaming along in 4th gear, but not going any faster - my mate was changing to fifth just for some relief.

if i had another z4 i'd probably do a backbox delete... did that with an older 328i and that sounded pretty decent at high rpm, even if it was a bit coarse at low rpm.
 
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