Karbonius Carbon Fibre Stock S54 Plenum

[///MBan]

Karbonius has confirmed they will make a test plenum to check the viability of the project. There is no timeline yet as they need to see if any of the parts from their CSL intake can be carried across. I’ll post an update when I have more information.

[TosM3]

Just out of curiously, what would this look like

[E46 M3]

Just out of curiously, what would this look like

Go lift your hood and take a look at the stock plastic box, now imagine it it in carbon fibre.

[///MBan]

Quick update: Karbonius hopes to start this project in May.

[/M3]

The carbon fiber has very little to do with the sound. It is the huge opening of the CSL air box that lets out the symphony of the S54. You can literally cut open your factory S54 intake manifold and install a panel filter. You will achieve the %90 sound that of a CSL carbon fiber air box. But you will have to go Alpha-N regardless. If it is just for the jewel under the hood while staying with a MAF, that’s totally up to the individual.

[heinzboehmer]

You can literally cut open your factory S54 intake manifold and install a panel filter. You will achieve the %90 sound that of a CSL carbon fiber air box.

Ah I remember that thread.

https://www.e46fanatics.com/threads/one-off-custom-oem-style-air-intake-manifold-very-loud.988874/

[tlow98]

A question on MAP tuning for the experts in here…

What is the current gold standard for the MAP tunes?

I’m moving back to the CSL airbox setup, and tbh, I wasn’t over the moon with my original MAP-based setup.

It was:
- evolve carbon airbox (non CSL replica)
- MSS54HP w/CSL Tune + stock MAP sensor
- full stock US exhaust

The issue I had was low rpm hesitation when I changed throttle openings in a large degree, even while in a low gear. The car was super strong, dyno’d 285hp stock at Dean’s performance (a la flipm3 back in the day) so I know the VANOS was in good shape.

maybe it’s bc of the Evolve box? Anyway, alpha N felt smoother but less powerful for the week that I ran Alpha N while waiting for the CSL setup to be completed.

this was back in ~2015

[///MBan]

Another quick update: Karbonius has started the design and hopes to provide some details soon.

[9kracing]

I'd be in if prices are close to what was listed

[///MBan]

I'd be in if prices are close to what was listed

Thanks - the price should be pretty close to estimate provided but I'll put a note on the list to say your interest is subject to price.

[///MBan]

We're getting closer. Karbonius has advised that this month they hope to have the provisional mould and first prototype ready for test fitment. If that goes well, they will manufacture a high-quality mould and produce the real thing.

[///MBan]

Karbonius has finished the prototype plenum - see the pictures below. This was straight out of the autoclave, so it hasn't been cleaned up at all. Next week they will be testing the fitting and sound. Fingers crossed!

[heinzboehmer]

Oh interesting. Looks like one of their regular CSL airbox filtered sections and a new piece with an inlet that accommodates the stock MAF elbow. Is that just for prototyping purposes? Or is that the design that they're planning to produce?

If this is the final design, I might be interested in purchasing just the portion that fits the stock MAF elbow (if possible). I plan on running my full karb airbox 99% of the time, but that piece would make smogging the car easier. Would just need to swap that out instead of the entire airbox.

Swapping the whole thing out isn't hard or too time consuming, so I would probably only be interested if the price is decently low. Or if all the bay area members pitch in for a communal smog airbox section lol.

And as always with these guys, quality looks awesome, even just straight out of the autoclave.

[///MBan]

I've already asked about the current two-piece design being just for the prototype, or whether it will be used for the final product. I'll update when I have a reply. Earlier Karbonius mentioned that they wanted to see if they could re-use other parts they already have (i.e. the filtered section from the CSL plenum), so this could be part of their plan.

[///MBan]

To confirm a few more details:
- the plenum will be made in two pieces together but bonded together to result in a one-piece (so no CSL air filter and it won't help with quick changes for emissions testing)
- carbon fibre trumpets will be fitted
- Karbonius opted for a flat top surface (versus the having humps like the OE plenum) as this provides a louder sound. They were also not aiming for an exact reproduction.