Karbonius Carbon Fibre Stock S54 Plenum

[JDMaflac]

For anyone interested on how it sounds outside of the car.
-Karb oem box
-eventuri intake
-euro headers
-oem section 3

https://youtube.com/shorts/aQZkC4ojcZ8?si=x6ES3Ep1ds2CAicZ

**Also in my case when I experienced the leaks, Karb had me send back the box on their dime so they could reseal. At least that’s what I thought, instead they gave me a new box entirely with the new anti slip ring attached.

[maupineda]

Would you happen to know of the ring is pre installed or we have to put it on?

Also, on a more direct note to your situation, I’ve been reading your posts on both the csl intake and this solution. What do you think is the sound difference between the two? Is the volume similar to the csl intake with the eventuri intake and CF oem plenum? Is the tone the same?

Is already installed.

no, the sound is similar in nature but tone and volume are different. The volume is not as loud and it is a higher pitch, not as gutural and deep as the CSL. I added the sound generator to increase the volume in the cabin and it is still very special, but not the same.

if I had to do it from scratch but knowing what I know, I think I would still do the MAF setup. You can read the mapping thread of some gurus from here that will agree with me that finding a good map is tough, and that is knowing that on my platform there is a very good option, but beating the MAF setup is a challenge.

[elrichmeister]

Man, i want this intake plenum so bad lol. I have eventuri intake, but must take care of RACP reinforcement first, then inspect and address Vanos. Maintenance before mods...

[jpy1980]

Yes. They have now a ring. I had mine replaced under warranty and the new one fixes all the issues.

Would you happen to know of the ring is pre installed or we have to put it on?

Also, on a more direct note to your situation, I’ve been reading your posts on both the csl intake and this solution. What do you think is the sound difference between the two? Is the volume similar to the csl intake with the eventuri intake and CF oem plenum? Is the tone the same?

[maupineda]

Yes. They have now a ring. I had mine replaced under warranty and the new one fixes all the issues.

[jpy1980]

Any updates on this? Has the issue with the intake elbow slipping off and the leaky box been addressed in the newer models?

[TeddybearCup]

Thanks Teddy!! I had sent them an email yesterday so waiting to hear back with what they say, not looking forward to removing the airbox again but will if I have to. May I ask what was the turnaround time and if you were responsible for any fees/shipping/VAT?

I believe shipping was a couple of weeks and Karbonius helped organize it. I can't remember if I paid any fees (if there were, it wasn't anything scarring), and would certainly have that conversation fresh with Karbonius if I needed a fix.
They provided good support and stood behind their product.

[JDMaflac]

Contact Karbonius. I had a leak from the upper seam where the two halves connect and it was enough to require our car to have 10% STFT on lower loads and run a bit poorly from having to make the adjustments.
I believe the ECU can handle around 20 or 25% fuel trim adjustments before it gets truly problematic, but the adjustements are reactive so you get slightly worse operation as a result.

I ran a smoke test as well for this and sent it to Karbonius. They sorted me out after I shipped back the airbox. New airboxes are smoke tested before shipping as a result of my interactions with them, but the early ones were not.
Unmetered air getting sucked in means an underreading MAF, leading to the car having to increase fuel trims.

Thanks Teddy!! I had sent them an email yesterday so waiting to hear back with what they say, not looking forward to removing the airbox again but will if I have to. May I ask what was the turnaround time and if you were responsible for any fees/shipping/VAT?

[TeddybearCup]

I finally installed my Karb OEM airbox 2 weeks ago after running my Eventuri intake for a few months to get acquainted with the sound (other mods: euro headers, X Rasp section 1, stock section 3). I wanted to make sure my installation went correctly since I had to use worm clamps on the manifold side and didn't want to snug up too much on the carbon fiber piece so with the help of a friend we did a smoke test. Found out in the shared video that both bottom corners of the airbox itself leaks, granted the engine doesn't throw any lean codes but I feel like there's a slight hesitation/choke in the upper rev range (no custom tune other than CSL tune to accommodate for the headers). I wanted to see if anybody else have ran similar tests and if I should should reach out to Karbonius themselves? Another question I have, what type of impact would this have with unmetered air being sucked in, if any?

Contact Karbonius. I had a leak from the upper seam where the two halves connect and it was enough to require our car to have 10% STFT on lower loads and run a bit poorly from having to make the adjustments.
I believe the ECU can handle around 20 or 25% fuel trim adjustments before it gets truly problematic, but the adjustements are reactive so you get slightly worse operation as a result.

I ran a smoke test as well for this and sent it to Karbonius. They sorted me out after I shipped back the airbox. New airboxes are smoke tested before shipping as a result of my interactions with them, but the early ones were not.
Unmetered air getting sucked in means an underreading MAF, leading to the car having to increase fuel trims.

[maupineda]

Is a Z4M, so only option is Alpha-N.

[RazorM]

I had this concern when I inspected my box, and I was 90% certain it was not air tight, that said, my car has been custom map and I don’t notice any issues, but my map for sure addresses any extra air via fuel trims, and all within the ecu failsafe as I don’t have any check engine light, even before mapping. I also noticed zero change in performance from my CSL Karb, so I am sure I am not missing anything other than the wonderful sound, but I also no longer have the lumpinesses I had with the CSL setup.

that said I kept my CSL and OE air box if I ever want to go back to either

What do you mean by “lumpinesses” when you ran CSL airbox? Did you run on alpha n or map?

[maupineda]

I had this concern when I inspected my box, and I was 90% certain it was not air tight, that said, my car has been custom map and I don’t notice any issues, but my map for sure addresses any extra air via fuel trims, and all within the ecu failsafe as I don’t have any check engine light, even before mapping. I also noticed zero change in performance from my CSL Karb, so I am sure I am not missing anything other than the wonderful sound, but I also no longer have the lumpinesses I had with the CSL setup.

that said I kept my CSL and OE air box if I ever want to go back to either

[JDMaflac]

I finally installed my Karb OEM airbox 2 weeks ago after running my Eventuri intake for a few months to get acquainted with the sound (other mods: euro headers, X Rasp section 1, stock section 3). I wanted to make sure my installation went correctly since I had to use worm clamps on the manifold side and didn't want to snug up too much on the carbon fiber piece so with the help of a friend we did a smoke test. Found out in the shared video that both bottom corners of the airbox itself leaks, granted the engine doesn't throw any lean codes but I feel like there's a slight hesitation/choke in the upper rev range (no custom tune other than CSL tune to accommodate for the headers). I wanted to see if anybody else have ran similar tests and if I should should reach out to Karbonius themselves? Another question I have, what type of impact would this have with unmetered air being sucked in, if any?

[JDMaflac]

Designed a super basic bracket for the oil dipstick, because my aluminum screwed together L brackets unscrewed from all the vibrations and started clanging against each other every once in a while. Super annoying!

I hosted the file on my site listing for folks with a printer. Not super motivated to print these out for people because of how small they are and how basic the design is, but can do so for anyone needing one.

Ordered 1

[///MBan]

I'm not sure if this is an issue for the E46 guys, but Z4M users have found that the factory rubber intake elbow slips off the opening to the plenum. People have used tape to stop this from happening but Karbonius now has a permanent solution. From Karbonius:

"We have developed a solution for the slipping of the tube
Can tell the people on the group they can ask for a kit and we will ship
It includes glue and a laser 3D printed nylon frame"

Pictures below.