Karbonius Carbon Fibre Stock S54 Plenum

[terra]

Sucks because its a PITA to go MAP and the cost is basically a flex for 40hp. which makes me wonder why not use what they have and develop around a maf to see the results from testing

Because it's really not that much of a pain, and in the case of the Z4M going straight "alpha N" is more viable since those have wideband O2s.

[Carbon.dre]

makes sense just curious now on the power figures

[///MBan]

Karbonius has test-fitted the plenum and made a video, as well as videos of the same car with a completely stock intake and the same car with their CSL-style intake. I've posted the videos below. Karbonius are on holiday until 30 August but provided a few comments when they sent me the videos:

"I just sent you 3 videos,
1- OEM airbox, you can see the results in dB , minimum 72,2 and maximum at 5000 rpm 106 dB
2- CSL airbox , minimum 79 , maximum at 5000 rpm 130.2 dB
3 -Karbonius OEM style airbox, minimum 74,3 , maximum at 5000 rpm 118,7 db.

Sorry for the quality of the video, maybe doesn't´do justice comparing with real sound, but I think you can hear the difference between the 3 boxes.
We have 2 dB more in the low measure and +12,7 dB in the revolutioned measurement . The Karbonius OEm style airbox is not as louder as the CSL airbox, but clearly louder than the OEM one.
We checked on the car and drove few kilometers, and we could hear clear the sound of the box, specially between 2500 to 4000 rpm, driving at few rpm and putting gas in 4th or 5th gear is easy to heard."

I also asked a couple of questions:
Q. Will the price be the same as originally estimated (1,200 euro)?
A. Yes , at the moment we will keep the price, but I´ll confirm you when we will make the 2nd unit!

Q. How long will it take to put into production?
A. We can start the production in middle of September

Videos:
Karbonius carbon fibre S54 plenum
https://youtube.com/shorts/NtCRPz1705A?feature=share

Karbonius CSL-style intake
https://youtube.com/shorts/D8S_IVLXTEc?feature=share

OEM
https://youtube.com/shorts/LV8jRFmXMyg?feature=share

[heinzboehmer]

Not going to add anything of substance really with my comment, but I just wanted to say this is awesome. I'm sure everyone involved appreciates the communication and transparency. Karbonius created an entirely new product just to see how it turned out because some people on the internet were interested and that makes them seem even cooler to me than they already did.

I'm glad it actually worked. This + an eventuri might be the ultimate MAF setup. Also interesting to see the flexing of the carbon with the more restrictive intake path (compared to CSL).

[simonnim]

Is it me or is that airbox flexing inwards?

[WoGGo]

Is it me or is that airbox flexing inwards?

I believe that is just the reflection of the lights above changing as the whole engine moves.

[///MBan]

Is it me or is that airbox flexing inwards?

There have been a few similar comments on other forums - I'll ask Karbonius about the flex.

[LSBNick]

Not going to add anything of substance really with my comment, but I just wanted to say this is awesome. I'm sure everyone involved appreciates the communication and transparency. Karbonius created an entirely new product just to see how it turned out because some people on the internet were interested and that makes them seem even cooler to me than they already did.

I'm glad it actually worked. This + an eventuri might be the ultimate MAF setup. Also interesting to see the flexing of the carbon with the more restrictive intake path (compared to CSL).

IMO, if you grab this and a new eventuri intake, you might as well just grab the Haimus Racing carbon airbox which runs about $1800 IIRC. Going with this and a new eventuri puts you easily over $2k for the full setup.

This project is awesome just simply because Karb took the time to even build one just because some E46 nerds were curious how it would come out haha. Great to see a company support enthusiasts on what’s now a 21 year old chassis with new parts.

[Nate047]

So basically it's a little louder and makes the same power as stock, or am I missing something?

[S3diment]

IMO, if you grab this and a new eventuri intake, you might as well just grab the Haimus Racing carbon airbox which runs about $1800 IIRC. Going with this and a new eventuri puts you easily over $2k for the full setup.

This project is awesome just simply because Karb took the time to even build one just because some E46 nerds were curious how it would come out haha. Great to see a company support enthusiasts on what’s now a 21 year old chassis with new parts.

The math isn’t as straightforward for those with MSS54 DME’s.

[digger]

Imo it looks out of place having the oem plastic intake / airbox

[///MBan]

The intention was not to make any more power, just to give some of the CSL sound while keeping the MAF and not needing any kind of a tune. Adding 50% of the sound volume achieved with the CSL intake is pretty impressive to me when the standard airbox is still in place. I also really like the change in tone achieved with the carbon plenum. I suppose it's about expectations and some people will be happy with what has been achieved while others won't be. The flexing is something a few people have mentioned, so I'll see what Karbonius has to say about that.

[maupineda]

this, plus my eventuri, plus my sound generator, I bet will be even better than my current Karb box, and no more Alfa-N ==> Win

[///MBan]

Okay, so I have a couple of questions to ask Karbonius:
- can the plenum be strengthened so it doesn't flex so much?
- which rubber boots were used in the design (my understanding is that Z4Ms and post-2004 E46 M3s have one type of boot (part number 11617835861) and pre-2004 M3s and M3 CSLs have another kind (part number 11612466477) and they're not interchangeable. This also means the OE clips on the plenum side are different - Z4M is 11617835320 and pre-2004 M3/CLS is 11617830306)

Before I go back to Karbonius I want to check if anyone else has questions or comments?

S54Mickey
GemsZho
CheckA
jrgatfh
R717
9kracing
theBMWaddict
Jimm3

[///MBan]

Karbonius have come back with responses to my questions:

Q. There appears to be quite a lot of flex in the top of the plenum. People have expressed concern that this could result in the unit failing over time, probably where the two parts are bonded together. Is there a way to strengthen the top? Or do you think this isn't needed?

A. Yes, a lot of flex on the top, this is because this unit was made without the inner pilar reinforcement, we are installing a inner reinforcement ( like the ones we are using in the CSL airbox) and we will test again, I hope not to loose too much sound!! Anyway ,I´m not worried about the union between 2 pieces, I´m sure will not fail on this area, we are using a very good glue, it support a lot of cicles of flexion and traction

Q. Is it possible to order the plenum without any logo or writing on the top?

A. Yes , no problem, we could send it with the Mpower sticker separately ( not glued under the varnish)

I also asked about the rubber coupling and they advised that their plenum is designed to work with part number 11617830265. This is part from the CSL and pre-2004 M3.
https://www.realoem.com/bmw/enUS/pa..._CSL&mg=11&sg=40&diagId=11_3517&q=11617830265

Can anyone confirm if Z4 and post-2004 M3 rubber couplings work with the CSL airbox? I have never read that they DON'T, but would like to confirm as the rubber boots are quite expensive.