Karbonius Carbon Fibre Stock S54 Plenum

[maupineda]

I have both, and replaced my Karb CSL with the new OEM style and I can tell you sound wise they are the same. CSL has higher volume, but the 10% or so difference is not worth the loss in smoothness when giving up the MAF sensor. No matter what anyone says. At least on the Z4M Alpha-N v MAF is no contest. MAF is just more consistent as it is a true close loop system with infinite adjustment, whereas Alpha N is limited to pre defined tables.

[Slideways]

I have both, and replaced my Karb CSL with the new OEM style and I can tell you sound wise they are the same. CSL has higher volume, but the 10% or so difference is not worth the loss in smoothness when giving up the MAF sensor. No matter what anyone says. At least on the Z4M Alpha-N v MAF is no contest. MAF is just more consistent as it is a true close loop system with infinite adjustment, whereas Alpha N is limited to pre defined tables.

Which Alpha-N tune are you using on the Z4M?

[EthanolTurbo]

Anyone got one of these for sale? I can test it out, record it with my high end mic and recording setup and then record a Karb CSL box for comparison.

[maupineda]

Anyone got one of these for sale? I can test it out, record it with my high end mic and recording setup and then record a Karb CSL box for comparison.

Karbonious?

[PetrolM3]

I have both, and replaced my Karb CSL with the new OEM style and I can tell you sound wise they are the same. CSL has higher volume, but the 10% or so difference is not worth the loss in smoothness when giving up the MAF sensor. No matter what anyone says. At least on the Z4M Alpha-N v MAF is no contest. MAF is just more consistent as it is a true close loop system with infinite adjustment, whereas Alpha N is limited to pre defined tables.

To confirm, you're saying OEM style airbox sounds almost the same as CSL but WITH EVENTURI, correct?

I think it's important to state that you also have the eventuri every time you claim it's almost the same thing.

Eventuri is $1000 and once you consider that, the proposition no longer makes sense for E46 M3 customers who can have the true CSL box with CSL software (remember - the people on this forum have E46 M3 cars, not Z4M so we don't need to deal with alpha-N like you did. We have a different DME than you do and we can run OE CSL software which is just as good as the MAF set up). It sounds like your alpha-N dislikes ruined your true CSL airbox experience hence you're so fond of the OEM unit for the Z4M. I can see how most Z4M owners would agree with you. However, if you had an MSS54HP DME, let's be honest - would you REALLY buy an OEM box and an Eventuri when you can have the true CSL box with OE software and MAP sensor for the same money?

[maupineda]

Which Alpha-N tune are you using on the Z4M?

I used two, Epic and Severn, the latter was by far the best. Epic's was evidently too rich, with too much smell and tailpipe soot, fuel trims were off also. In all fairness, I do not know if Epic's was just an off-the-shelf map, or it was custom, but Epic would not respond to my request to remap the car remotely, there simply was no interest for a small sell LOL. Severn did custom tune via data logging, which on the Z4M is "easy" as it has wideband sensors out of the box. Severn's was much better, and smoother when running close to mapped conditions, but the car may still be inconsistent in some transient throttle inputs. I know this could be improved by spending more time, but it would only be ideal to certain conditions, and I drive the car at sea level (high heat, high humidity), and at altitude (2.2km above sea level, dry, and warm weather) and of course anything in between, so Alpha-N would never be able to accommodate for those changing conditions as the MAF setup does.

Epic's would buckle/hesitate/kangaroo in the 2k to 3k range under low load conditions after coming back on the throttle, Severn reduced this greatly, but it would still happen from time to time. Also, with Severn's map, the delivery under WOT was very linear and consistent, and the car would reach redline in the typical S54's crescendo fashion, Epic's map would tailor off after 7500 rpms.

With the MAF map (which by the way at this point is just the BMW stock map), the car is incredibly smooth, and all throttle transients are perfect with no hesitations at all, under any condition. Moreover, Alpha-N is not OBD2 capable, so I wold not be able to meet emissions.

Next in my build is Severn to remap my car once I put the Eventuri back on, so is mapped to the final hardware stage.

Lastly, Severn's service is just fabulous, and he is active in the development of the Z4M's MSS70 ECU (see below).

https://www.zpost.com/forums/showthread.php?t=1969117

[maupineda]

To confirm, you're saying OEM style airbox sounds almost the same as CSL but WITH EVENTURI, correct?

I think it's important to state that you also have the eventuri every time you claim it's almost the same thing.

Eventuri is $1000 and once you consider that, the proposition no longer makes sense for E46 M3 customers who can have the true CSL box with CSL software (remember - the people on this forum have E46 M3 cars, not Z4M so we don't need to deal with alpha-N like you did. We have a different DME than you do and we can run OE CSL software which is just as good as the MAF set up). It sounds like your alpha-N dislikes ruined your true CSL airbox experience hence you're so fond of the OEM unit for the Z4M. I can see how most Z4M owners would agree with you. However, if you had an MSS54HP DME, let's be honest - would you REALLY buy an OEM box and an Eventuri when you can have the true CSL box with OE software and MAP sensor for the same money?

I understand and agree with you in regards to the technical aspect of E46 owners being able to run the CSL ECU also, however, you are also shorting yourself with your assumption set above regarding cost. To the cost of the CSL box, you need to add the cost of all the ancillaries, and depending on how anal you are, it can be also not cheap. a quick list of what is needed...

MAP sensor
MAP piping (or CSL air rail)
DME Conversion
Wiring
IAT sensor
IAT sensor relocating wire harness
Map (ECU tunning)
CSL oil dipstick
CSL brake booster jet pump solenoid
Snorkel

I am sure the above would close the gap to the cost of the Eventuri, I am sure there is very little in between once you price it all up (the OE style box is also a bit cheaper). and if it was me, I would do it the most OE-like way possible, which ain't the cheapest.

And then there is the emissions part of it. swapping the OE style Karb box + eventuri to the OE items is simpler than undoing the CSL implementation, heck, in some states you may actually just be fine with the OE style karb box as it is OBD2 compliant whereas the CSL (either MAP or Alpha-N) gives headaches with OBD2 readiness flags.

All I am saying is that there is a new option, and depending on what your needs are, you can choose accordingly.

[T.J.]

And then there is the emissions part of it. swapping the OE style Karb box + eventuri to the OE items is simpler than undoing the CSL implementation, heck, in some states you may actually just be fine with the OE style karb box as it is OBD2 compliant whereas the CSL (either MAP or Alpha-N) gives headaches with OBD2 readiness flags.

This is why I’m not going that route! Seen enough NY state people not being able to pass the annual obd check

[PetrolM3]

I understand and agree with you in regards to the technical aspect of E46 owners being able to run the CSL ECU also, however, you are also shorting yourself with your assumption set above regarding cost. To the cost of the CSL box, you need to add the cost of all the ancillaries, and depending on how anal you are, it can be also not cheap. a quick list of what is needed...

MAP sensor
MAP piping (or CSL air rail)
DME Conversion
Wiring
IAT sensor
IAT sensor relocating wire harness
Map (ECU tunning)
CSL oil dipstick
CSL brake booster jet pump solenoid
Snorkel

I am sure the above would close the gap to the cost of the Eventuri, I am sure there is very little in between once you price it all up (the OE style box is also a bit cheaper). and if it was me, I would do it the most OE-like way possible, which ain't the cheapest.

And then there is the emissions part of it. swapping the OE style Karb box + eventuri to the OE items is simpler than undoing the CSL implementation, heck, in some states you may actually just be fine with the OE style karb box as it is OBD2 compliant whereas the CSL (either MAP or Alpha-N) gives headaches with OBD2 readiness flags.

All I am saying is that there is a new option, and depending on what your needs are, you can choose accordingly.

Some of those items are minor and some not even required but you forgot the CSL filter, the damn thing is really expensive!

However, you do agree that the cost is about the same which sort of proves my point in terms of OE-like set up which is undeniably cleaner, more desirable and must sound better and louder due to the larger opening...

I guess the only advantage of the OEM style + Eventuri combo is the easier swap for emissions testing. In my case, I don't have to deal with that any longer (Ontario, Canada).

[oceansize]

Some of those items are minor and some not even required but you forgot the CSL filter, the damn thing is really expensive!

However, you do agree that the cost is about the same which sort of proves my point in terms of OE-like set up which is undeniably cleaner, more desirable and must sound better and louder due to the larger opening...

I guess the only advantage of the OEM style + Eventuri combo is the easier swap for emissions testing. In my case, I don't have to deal with that any longer (Ontario, Canada).

For many emissions is the deal killer. Emissions compliance with say 70-80% of the sound and far less hassle will be completely worth it regardless of cost equivalence.

[PetrolM3]

For many emissions is the deal killer. Emissions compliance with say 70-80% of the sound and far less hassle will be completely worth it regardless of cost equivalence.

Fair - but in that case, is the OEM style airbox really worth the money if you'll be buying an Eventuri anyways which actually provides most of the sound? My understanding is Eventuri alone is about 60% as loud as a true CSL style box and while this OEM style airbox helps some, it's very limited because of the MAF tube diameter. So then an additional 10-20% of the sound of the OEM style unit costs another $1700-1800 with shipping, fees, etc... definitely not good value for the money. I get that some see this differently, heck even the true CSL set up is shit on by many in terms of cost vs value/benefit but I guess it's a matter of personal preference and opinion so to each his own...

[Casa de Mesa]

I get that some see this differently, heck even the true CSL set up is shit on by many in terms of cost vs value/benefit but I guess it's a matter of personal preference and opinion so to each his own...

Putting aside the emissions aspect...

I'm not sure who's shitting on it, but I definitely see the ~25hp +/- rwhp gains plus the full 100% induction sound/volume (based on above scale) provided by a CSL conversion as worth it. It's literally one of the best induction noises on the planet. So glorious.

[PetrolM3]

Putting aside the emissions aspect...

I'm not sure who's shitting on it, but I definitely see the ~25hp +/- rwhp gains plus the full 100% induction sound/volume (based on above scale) provided by a CSL conversion as worth it. It's literally one of the best induction noises on the planet. So glorious.

I've come across many who say $3K for an intake is ridiculous but you're preaching to the almost converted... if I make one more mod to my car it will be the full CSL intake from Karb. for all the reasons you already mentioned. My arguments above were regarding this OEM style + eventuri combo which in my mind isn't even an option considering price is the same. Even if I had to deal with emissions, I'd still go full CSL. If money was no object, it would have already happened but hopefully soon!

[maupineda]

the one thing though, many of us dismiss is the actual performance difference the CSL box has V a MAF setup. Take Marty's build journal in the M3Cutters forum as an example, in his build log there was nothing between CSL box and OE box + Eventuri in terms of performance, and that was on a cammed car. so there is that. How do you explain that? I think in terms of performance there is little to be gained if anything, both setups are similarly capable. Also the link I posted above shows a MAF car (Z4M) with an eventuri and a similar carbon box to Karb's OE style one delivering 350whp with stock cams but stepped headers and a dry sump.

Again, you are hearing all this from someone who has the two boxes, I have direct experience with the two on the same car, and they are equal in terms of experience, and I prefer the smoothness of my MAF setup, the volume is not different enough for me to think one is better than the other, and in the Z4M I have a sound pipe too, so is absurdly loud LOL, and BTW, I cannot use the sound pipe if I use the CSL box, so in my case, the OE style is better, how's that!

[Casa de Mesa]

I'm not here to pee in anyone's Cheerios. And I only took a small portion of the overall discussion and quoted it. Sound bites! There are pros and cons to everything and I definitely see a market for the OEM style Karb box. My only point is the CSL intake is stunning at full song. Pure music!