Z4M OEM Airbox Lid Modified with Carbon Sheets

[gwatson]

I've had an attempt to modify the original airbox lid with the hope that it will let out a little more induction noise. I'm certainly not expecting Gruppe M or AFE gains in noise, in fact I have no basis to expect anything, but it was just a little fun and very satisfying to do. It's only 0.4mm carbon, so very thin, especially compared to the plastic.

Carbon cost about £30 and £35 for a spare lid, so not the end of the world if it doesn't work.

Unfortunately the sealant won't be dry until tomorrow, so will have to wait until then to give you the result. If there is an increase I'll do the same with the bottom of the airbox. Adding a BMC panel filter too should (could) all help, not sure I want to come down the oiled filter route though.

 

[Woots]

I don't get how it'll make more noise?

 

[gwatson]

Thinner walls on the airbox lid where it's been cut and carbon sheets placed, should equal less sound insulation which may be robbing some induction noise. Maybe a little carbon resonance going on, who knows.

As I said, no real foundation for this other than the logic in my head, I just enjoy the tinkering

 

[Woots]

Did u make the carbon sheets? Or can u buy them pre made?

 

[gwatson]

Pre-made. I did think about making them, then I watched a YouTube clip on the process I coukdnt make it that thin with a kit anyway.

 

[Bing]

I think someone else did this - pilchardthecat maybe ? Anyway, pretty sure whoever did it said they got some resonance going on

 

[dalecan]

That's too funny. I am just waiting for my second airbox to come to try this! Let me know how it works out.

 

[gwatson]

For info, this is where I got the carbon sheet from:

http://www.carbonology.com/carbon-fibre-sheet-04mm-0016-thickness-c-2_50.html

305mm x305mm was enough, got a small square left which I may do another hole round by the MAF sensor.

 

[Beedub]

how does it sound??

 

[gwatson]

Well fitted it at lunchtime, I had to cut down one of the screws as it was interfering with the MAF gauze. Easily sorted though.

As for noise... well it's no Gruppe M that's for sure!In fact, the difference is minimal to be honest It is therer, between 2200rpm to 3200rpm, a little more bark, very subtle though and a random wouldn't notice. With the roof up it's almost more of a turbo sucking\induction noise, hard to explain. With the windows down and roof down it's a muted roar if that make sense.

The exhaust mod will definitely drown it out when I do that. It doesn't help I've not driven it for over a week either.

I think I'll take the gamble on a BMC filter and have a look at the bottom of the box tonight and see what can be done. It looks quite an awkward shape when I removed the filter at lunchtime. Hopefully some flat panels on the bottom and side.

I'm going for the accumulative effect now

Or should I just give up? lol....

 

[gwatson]

Quick update, I finally got round to the applying the "pilchardthecat maf screen mod" I can't comment if it's made any different on performance or throttle response as I only drove it round the block, will update on this later. But did I detect some more noise... I think so, but it could all be messing with my head

Link here for anyone interested - http://www.z4-forum.com/forum/viewtopic.php?f=9&t=52386&p=763216&hilit=carbon#p763216

I removed the bottom section of the airbox to see what I could do with it, it's certainly possible to put a 3 or 4 small carbon panels in, but it would be awkward shapes to cut. Also not sure the implications of removing the grid profile inside the airbox. I'll wait until I've done the rear exhaust mod.

Modified MAF screen on the left.


Also ordered a BMC filter:

 

[exdos]

I'm sorry to say that I honestly think you are wasting your time and spoiling a good OEM air-filter box.

Ask yourself why the AFE and GruppeM intakes sound different to OEM? It's because the inlet is wide open, thus acting like a trumpet projecting the sound of the engine at work. If you want slightly louder, I would suggest that you try removing parts 10,11,12 and 13 in the diagram below, but then you will lose some performance by not obtaining ambient air under ram pressure.

Alternatively, remove the lower half of the air-filter box and tape a K&N type filter to the top half of the box with duct-tape to seal around the filter, but again you will lose performance.

 

[carl]

Well fitted it at lunchtime, I had to cut down one of the screws as it was interfering with the MAF gauze. Easily sorted though.

I can't comment on the noise as I haven't heard it, but that looks terrible IMHO. Sorry.

 

[BMWZ4MC]

I thought it looked surprisingly good considering it's essentially a few CF elastoplasts covering ragged wounds in the airbox lid gwatson, you've made a good job of ensuring the CF plate is centred on the airbox lid - it's a shame you haven't achieved the desired increase in noise - have you any other ideas?

 

[exdos]

I agree that Graeme has made a very tidy job of his modification, especially since it is experimental R&D.

 

[Beedub]

i like the look of it , dont like the screws however.... i hope during extreme temps that bonding doesnt break up get sucked into the motor..... not that it would do any harm i guess, it would just get vaporised.

 

[gwatson]

If the temperature inside the airbox gets to 150 degrees that the sealant is rated to I'll have bigger problems to worry about

I fitted the BMC filter on Thursday night which has made another slight difference. I picked up a friend from the airport and he noticed a change in noise without saying something to him, so the combination of the three mods has made a small but noticeable difference. I'd say 5-10% difference...

I might trying removing some of the parts John suggested above, but the objective of the mod was to keep the airbox intact. Think I'll just move onto the exhaust mod now

 

[Beedub]

If the temperature inside the airbox gets to 150 degrees that the sealant is rated to I'll have bigger problems to worry about

I fitted the BMC filter on Thursday night which has made another slight difference. I picked up a friend from the airport and he noticed a change in noise without saying something to him, so the combination of the three mods has made a small but noticeable difference. I'd say 5-10% difference...

I might trying removing some of the parts John suggested above, but the objective of the mod was to keep the airbox intact. Think I'll just move onto the exhaust mod now

ever mesured underbonnet temps??? im not worried about the air flowing inside of the box....

 

[exdos]

Under bonnet temps won't get above your oil temp. The air-box temp will always be lower than that (unless you have a fire :fuelfire: :wink: )

 

[gwatson]

ever mesured underbonnet temps??? im not worried about the air flowing inside of the box....

Nope..... but you did get me checking the rating of the sealant and it's actually up to 250 degrees Celsius. You're surely not suggesting that it gets hotter than that given the average ambient temperature up here is about 14 degrees

http://www.granvilleoil.com/pdfTechData2.php?ptdID=134