Karbonius Carbon Fibre Stock S54 Plenum

[heinzboehmer]

I'll wait and see how everyone else goes with the CSL reservoir bracket lol. I remember on the old forums someone had come up with bracket that didn't need drilling but can't find anything.

Found this: https://nam3forum.com/forums/forum/m...tting-too-high

[TeddybearCup]

Ugh, two roadblocks, I can't get all the boots on at the same time, and the little hose at the bottom of the plenum, near the engine, has two clips broken and keeps popping out when I'm moving the intake around. Calling it a night. So fucking close.

[heinzboehmer]

Ugh, two roadblocks, I can't get all the boots on at the same time, and the little hose at the bottom of the plenum, near the engine, has two clips broken and keeps popping out when I'm moving the intake around. Calling it a night. So fucking close.

1. Make sure the "wishbone" that the rubber isolators rest on is in place correctly. Not rotated or bent upward/downward. In my experience that has always been the culprit when I can't get the boots on. Other suggestion in to tilt the airbox up on the filter side and make sure the tops of all the boots are in place, then rotate down and push towards the engine at the same time. Might take some wiggling to get all the boots fully seated.

2. That bottom port on my karb airbox was a bit too long and the connector also wouldn't stay clipped in, even though mine has all four clips intact. Had to file it down to get it to stay.

The port for the vacuum line coming from the brake booster also was too long. Had to dremel some material off of that too.

[TeddybearCup]

1. Make sure the "wishbone" that the rubber isolators rest on is in place correctly. Not rotated or bent upward/downward. In my experience that has always been the culprit when I can't get the boots on. Other suggestion in to tilt the airbox up on the filter side and make sure the tops of all the boots are in place, then rotate down and push towards the engine at the same time. Might take some wiggling to get all the boots fully seated.

2. That bottom port on my karb airbox was a bit too long and the connector also wouldn't stay clipped in, even though mine has all four clips intact. Had to file it down to get it to stay.

The port for the vacuum line coming from the brake booster also was too long. Had to dremel some material off of that too.

Thanks for the tips! I wouldn't have thought to shave down! I'll have a new hose coming to have intact clips and will make it easier to fit.

Wishbone I've definitely bent in the OEM removal and the lower hose finangling. Does mean there's basically now way I can get this done by Thursday sadly.

[maupineda]

I feel your pain. On the same boat. I have the intake but not the car 😝

[///MBan]

Ugh, two roadblocks, I can't get all the boots on at the same time, and the little hose at the bottom of the plenum, near the engine, has two clips broken and keeps popping out when I'm moving the intake around. Calling it a night. So fucking close.

How have you gone with the installation? Did you have any trouble getting the plastic elbow to seat properly onto the airbox entry? A zpost user had to use a couple of layers of tape to get it to stay in place

My CSL breather hose arrived today, so I'll be installing tomorrow and looking for tips from people who have already tried!

[TeddybearCup]

How have you gone with the installation? Did you have any trouble getting the plastic elbow to seat properly onto the airbox entry? A zpost user had to use a couple of layers of tape to get it to stay in place

My CSL breather hose arrived today, so I'll be installing tomorrow and looking for tips from people who have already tried!

Supposedly, it'll be coming today! If USPS is to be believe. (This piece: BMW E46 Crankcase Vent Hose Air Collector to Oil Dipstick Tube E36.7 E85 E86 for sale online | eBay)

I took the elbow piece out of the car and it does seem long enough to clip in, but I also noticed the part I ordered is an updated design vs the hose I currently have. My current hose is super basic, and the new one looks like it might have a one way valve.
Also, seems to be the main source of oil leaks on the car, judging by how gunked up everything was around the area, so I believe this end has been broken even before I took off the stock manifold.

For the breather hose up top, my plan is to still just use 3/4" ID hose, which I have on hand.

EDIT: GUH, USPS delivery delayed till tomorrow

[maupineda]

Here it is the final product...

After driving the car for 2 years on Alpha N, now that it is running on a MAF she is butter smooth, even when my car had been dialed in and the tune was pretty good, however, the MAF setup does show its benefits. throttle transients are perfect and seamless, whereas the Alpha-N could be jerky at times. also, I don't notice any drawbacks in power, the MAF map is just as good for power according to my butt dyno.

[jrgatfh]

Here it is the final product...

After driving the car for 2 years on Alpha N, now that it is running on a MAF she is butter smooth, even when my car had been dialed in and the tune was pretty good, however, the MAF setup does show its benefits. throttle transients are perfect and seamless, whereas the Alpha-N could be jerky at times. also, I don't notice any drawbacks in power, the MAF map is just as good for power according to my butt dyno.

What are your impressions on sound comparison between the CSL style air box and this OEM CF box?

[maupineda]

What are your impressions on sound comparison between the CSL style air box and this OEM CF box?

If it was just for sound, not worth it. The tone is bit deeper compared to the OE plenum, with a tiny bit of resonance (the CSL wailing sound we love, but quiter). However, pair it with an Eventuri and it gets you the real deal. Buck to buck is the same too, as tune is expensive, 1k in the case of the Z4M, the eventuri is about 850, so a bit cheaper but the key benefit for me is I have none of the draw backs of loosing the MAF. And the Karbonius OE style airbox is cheaper too.

[TeddybearCup]

Got the manifold installed this afternoon! Been helping a friend with installing an Accusump on his E89 since.
Final issue is the lower larger hose, the one on the outer right on the bottom, which had its ring clip broken off. So it fell off a few times while driving, before I duct taped it in place. I ordered a similar looking BMW hose from Amazon ($16) with hopes of stealing that hose end. Otherwise, gotta shell out $76 for the actual oem hose
Overall install: The tips above helps a ton! WAY easier.
We had some struggles with air leaks at first. Between that, plus that smaller hose from earlier not seating correctly, plus the K&N to manifold not quite sealing at first. The smaller hose I got was longer than original, and has a one way valve, which is cool. This also made install trickier though due to length.

Video from inside the car below.
Will temper expectations here: the recoding sounds very similar to each other, but in real life, the tonal difference and volume from the front of the car is way more apparent. The phone blends together the exhaust (Borla) and intake. With OEM manifold, I'd say the intake was half as loud inside the car as the exhaust. With the Karbonius, it seems around as loud. The tone is a bit different as well.

I now need to find an Eventuri intake, because having a K&N next to this thing just feels wrong. (If someone in the midwest has one I can swap in for comparisons, let me know! Just don't have the budget to spend another grand on this car right now, with winter here)

EDIT: Forgot to mention. Weighing both OEM vs CF box, the CF box was 5 lbs lighter! Was a nice bonus to lose that from the top of the engine.

[PetrolM3]

So it seems that the oem style CF airbox is far from sounding like the CSL airbox without an open element aftermarket intake like the k&n or eventuri. This to me makes it not worth the money, no offence to anyone. I mean - sure, you keep your MAF and don’t need a tune but there is no power increase and barely any sound improvement for $2000. What’s the point then? Also, k&n is garbage and our cars don’t run well with them - speaking from experience. Those who think their maf k&n cars run better than a CSL airboxed and properly tuned car are fooling themselves.

In my opinion, Eventuri by itself is a better value. Otherwise get the real deal - CSL airbox with a CSL tune. Thanks to those who shared their findings. Cheers

[TeddybearCup]

I think most people who bought these are planning to run them with an aftermarket intake, and it's pretty obvious the CF airbox with OEM intake would be much quieter, both from logic around how sound travels and from early videos from Karbonius themselves.

Me and my wife both found the result to be noticeable compared to the OEM manifold and K&N alone.
FWIW, we've had the K&N since buying the car with it, and have also heard issues about how the car runs with one, hence wanting to swap to an Eventuri once budget permits. I don't think there were any people making claims that a K&N intake would run better than a properly tuned car on the CSL intake.

[Maxima SE]

We need to get Karb to make an intake for it., especially since most people seem to be getting one anyway.

[///MBan]

I got my Karbonius plenum installed yesterday but didn't get a chance to have a proper drive until today.

Notes on the installation:
- pretty straightforward, even for someone like me that isn't very experienced.
- I used silicone tape around the plenum opening. This gives a grippy surface without leaving a residue.
- I had some trouble with the location of the dipstick - it was too close to the plenum and rubbed when I was putting the plenum. In the end I used rubber washers on the mount to space the dipstick away from the plenum, which worked fine (see one of the images below).
- The hose that comes from the elbow (only Z4s have this) joins up with the electrical conduit that is mounted to the side of the dipstick. There is a mount on the standard plenum for these but not the Karbonius plenum. I zip-tied them up but it's not ideal (see photo below).
- I tried to install the stock air filter housing but it was contacting the electrical conduit on the side of the dipstick and the dipstick itself. Even if I hadn't of used the spacers, it would have been close. So, I just installed my Eventuri straight away. Bit of a bummer as I wanted to do some tests with the stock air filter housing.

Notes on Karbonius plenum performance
- After GuggagZ4M said with an Eventuri it was equivalent sound-wise to the full CSL intake, I had some pretty high expectations, and it didn't quite live up to them.
- Having said that, I had a long drive today and there is a definite change in tone and increase in volume. Particularly, the CSL 'warble' is much clearer now. Low revs (~3,000rpm) in 3rd and 4th really accentuate the sound and overall, the intake is just more present everywhere all the time.
- I did a freeway on-ramp today with concrete barriers and the sound was epic! I stuffed up the recording up of this unfortunately.
- I've never been in a car with a CSL intake and I'd be really keen to see how they compare.
- Overall, I'm happy with the plenum and knowing what I know now, I would still buy it.

I made a video, which includes the car in stock form, with Supersprint V2 headers and cat'd S-pipe, and then with headers, s-pipe, x-pipe, Powerloops and Eventuri and the current spec which is all the previous except the x-pipe (which I took off a while ago) plus the Karbonius plenum. I included the videos of the stock intake with the headers and s-pipe because when I added these it was much harder to hear the intake. So, this is probably the best baseline for the Karbonius plenum. Sorry for the funny framing in some of the videos - no one wants to see my face!









Youtube link: