Why do all the CSL like carbon boxes ditch the MAF ?

[MBan]

Okay, I received a response from Eventuri:

"We did consider making this but due to the age of the car now, the demand won't be enough to justify the development costs."

As due diligence I will check with Karbonius but I expect a similar response.

At the same time I'm going to contact a few carbon fibre places close to me that do custom work. I think small places that do custom work for race cars is going to be the best bet, but quality (aesthetic in particular) may not be up to Eventuri / Karbonius levels.

[mattfwalters]

Originally Posted by pokeybritches

I tend to go against common thought and consider alpha-n to be a glorified limp mode. The only advantage to alpha-n is the reduction in background compensation tables used by the ECU, which leads to more straightforward tuning. But, it also takes a whole lot longer to get a car dialed in with alpha-n since the base mapping is less flexible and must be more accurate. Even if a car is dialed in perfectly for exact weather conditions on a specific track, it will most likely need to be tweaked when environmental conditions or locations change. Alpha-n is a whole lot of effort to cripple a car, and it is an 80% solution at best.

-snip-

I don't know your background here, so if I'm preaching to the choir, consider this a contribution to the general domain knowledge.

I think you're dead on. Almost every manufacturer "limp mode" is either alpha-n / speed-density or some very similar thing. That said, as a nerd with an embedded systems / electronic engine management background, there is a more subtle advantage to the simplicity of alpha-n in a race setting than ease of tuning: any computer, embedded computers in particular, can execute a limited number of instructions per second - and older / most embedded computers tend to require more time to execute floating-point multiplication, like scaling based on a lookup table, than almost any other operation. So every sensor+compensatory table I don't need to consult per 720* of engine rotation gives me additional clock cycles - potentially many of them - that I can use to calculate spark+fuel timing / etc more precisely, support higher RPM without losing timing granularity (higher engine speeds == fewer instruction cycles per revolution to do math), etc. I get more precision at higher engine speeds without having to invest in developing new engine control hardware (very expensive + very long lead times) - and that's my guess about why the CSL program used a-n. Tuners tend to use a-n for the reasons you suggest and also because it's already baked into almost every ECU as the limp-home mode; reverse-engineering a-n from bytecode is much less complicated than reverse-engineering whatever brake-specific adaptive management routine(s) that same smog-legal ECM code has to run.

Short version: hoo boy, do I agree with you that MAF delete on most cars is silly; that said, racing programs sometimes have goals that smash up against engineering budgets / timelines, so they make trade-off decisions that are stupid for road cars.

[grannyknot]

@MBan, It doesn't sound too promising.
As I understand it, the great sound you get from a CF CSL type air box has more to do with the carbon fiber "resonating", or at least that's what I have read.
So i was playing around with idea of picking up a spare stock S54 air box from ebay, make a complete negative mold of the top of the box then cast a carbon fiber positive section of the top of the air box.
Then cut the top off of the air box and replace with new CF lid cementing permanently in place. The new CF lid would look identical to the original box but made out of CF.
Sure lots of work but if that much CF could improve the induction sound then I think it might be worth it.
It could also end up being a complete waste of time and materials so I thought I would throw it out there for comments.
The section I'm talking about is within the red line.

[MBan]

Originally Posted by grannyknot

@MBan, It doesn't sound too promising.
As I understand it, the great sound you get from a CF CSL type air box has more to do with the carbon fiber "resonating", or at least that's what I have read.
So i was playing around with idea of picking up a spare stock S54 air box from ebay, make a complete negative mold of the top of the box then cast a carbon fiber positive section of the top of the air box.
Then cut the top off of the air box and replace with new CF lid cementing permanently in place. The new CF lid would look identical to the original box but made out of CF.
Sure lots of work but if that much CF could improve the induction sound then I think it might be worth it.
It could also end up being a complete waste of time and materials so I thought I would throw it out there for comments.
The section I'm talking about is within the red line.

If you've got the skills and time, why not? Michael9218 may be able to advise since he has plenty of CF fabrication experience?

I haven't heard back from Karbonius yet, but I remember reading somewhere that they aren't good replying to email but do reply to Facebook messages. I'll try that but I'm not holding out much hope.

I think I'm going to talk to the CF fabrication shop I found near me and see what they say but will need to re-charge my car account post-suspension refresh.

[MBan]

Karbonius replied to me on Facebook messenger and their response was slightly more positive than Eventuri. See below. I have asked for a rough price per piece but haven't hear back yet. So, could we realistically find 20+ people willing to put their dollars on the table for this? I interpret the final sentence to be saying that they would make the test as long as we had 20 interested people interested, but these interested people don't actually have to commit until the product is produced.

Thoughts?

"Hi Michael, thanks so much for contacting us with so interesting topic!! Isn´t the first time someone asking for this!!

Yes, we could do it, but there are any problems with this, the first is the coist of the molds!! an standar mold in GF only to make 20 or 30 pieces , could cost around 3000€, and then the pieces.. this is the first problem..

the second, is until we made the first unit we didn´t know what will be the sound, if louder or lower sound comparing with CSL, at first I would say lower than CSL, and this could be a problem, expend a lot of money on the mold and finally didn´t get the expected sound !!!

We could make a test, but we should have at least 20 interested persons in it!!"

[grannyknot]

Count me in as an "interested person"!
It might be a good idea to start a dedicated thread to get the attention of all members, at the moment we are lost at the end of the OP's unrelated thread.

So they are saying they are willing to invest 3000 euros just to find out what it will sound like?
It would be good to hear from CSL type airbox owners if the induction sound comes from the front opening or if it emanates from the whole box, well come to think of it, Karbonius could answer that question.
Thanks for following up on this.

[maupineda]

I am in

[MBan]

Originally Posted by grannyknot

Count me in as an "interested person"!
It might be a good idea to start a dedicated thread to get the attention of all members, at the moment we are lost at the end of the OP's unrelated thread.

So they are saying they are willing to invest 3000 euros just to find out what it will sound like?
It would be good to hear from CSL type airbox owners if the induction sound comes from the front opening or if it emanates from the whole box, well come to think of it, Karbonius could answer that question.
Thanks for following up on this.

Yes; it seems Karbonius will do a test item if we can line up 20 EOI. I'll start a new thread and link to it from Z4-Forum as well. May be worth posting on NAM3 as well?

I have PM'd Michael9218 as he has the Turner plenum installed with a MAF via a custom CF adapter. That is likely to be the closest to a CF standard plenum that we are likely to get.

[MBan]

I was looking around on NAM3forum to find the best place to post for EOI for the carbon reproduction of the stock plenum and saw some group buys for carbon parts from a supplier in Germany. They don't have a reproduction of the stock plenum but they do have a more CSL-style intake that reduces down to what could be a MAF-compatible end. The description says it is "simply exhanged for the original part". It looks a bit long and on the wrong angle to line up with MAF in its stock location? See the link below. Is this a possible solution? I still like the simplicity of a carbon stock plenum, but this could be worth considering too (if it fits with the MAF):

https://carboproject.de/en/collectio...box-bmw-e46-m3