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

[Rombbb]

Is it because of the unrestricted wide open box, while MAF sensors require a smaller funnel to measure accurately ?

The rudimentary form of engine management via Alpha N tunes seems a step back from the more granular OEM method of simply measuring mass airflow.

The Evolve CSL box does make the best sound. Is there no way to get best of both worlds ? Like fabricating a MAF into it and keeping stock ECU ? Or maybe another brand that keeps the MAF ? (couldn't find any)

Alternative is the Eventuri cone filter, but that seems a compromise between OEM and Evolve.


EDIT : FOUND IT : looks pretty amazing and better price than the Evolve ��

http://store.motorsportsconcepts.com...3-z4m-maf.html

[Jsinghzzzz]

@pokeybritches Would be the most knowledgeable about this.

[maupineda]

I wish this existed, there should be a way to design a carbon box that gets you the benefits of induction noise, performance gains while retaining the MAF setup.

[Rombbb]

Originally Posted by maupineda

I wish this existed, there should be a way to design a carbon box that gets you the benefits of induction noise, performance gains while retaining the MAF setup.

EDIT : FOUND IT : looks pretty amazing and better price than the Evolve :

http://store.motorsportsconcepts.com...3-z4m-maf.html


Outdated :

Indeed, exactly my point

Am sure we're overlooking something

I understand the CSL uses a MAP (Manifold Absolute Pressure) sensor instead of a MAF up to certain revs after which it also goes the Alpha N route (only revs and throttle position to calculate fuel injection), but with a higher resolution data sheet in the ECU.

I guess BMW didn't lose the MAF for no reason on that car.

But the difference with aftermarket solutions is that those are Alpha N tune only and with a much more basic data table for fuel calculations, so despite what everyone touts I'm really not convinced it's the best way.

Especially not with changing air pressure, temp etc. There is some fallback on an O2 sensor, but that are only corrections to fuel flow afterwards. Not pro-active and granular like you get with simply measuring mass air up front.

To me those aftermarket N tunes seem more like a crippled or semi-limb mode. Yes they can provide higher hp numbers but only in optimal conditions. The consistency and reliability of performance suffers and that just isn't BMW.

On the M3 I think you can add a MAP sensor to the Turner Carbon box and flash the CSL software to have it perform like a CSL. But on the Z4M the ECU is totally different so that's not possible.

Real bummer, because apparently the carbon resonates the intake noise and it's supposed to be incredible.

Lots of good stories about the Eventuri scoop but it's also mentioned that it's only halfway the CSL sound-wise.

So getting a carbon box to work with a MAF would really be great.

[Michael9218]

Joshua (pokeybritches) is definitely the guy that needs to weigh in here. I recently worked with him on a tune for my track car. I came to him wanting an alpha N tune for a recently purchased Turner CSL box. He convinced me to reconsider and stay with the MAF. So I decided to have the best of both and fabricated a panel that allowed the use of the MAF with the CSL box. I wanted to use the CSL box as it looked to have better shaped velocity stacks for high rpm and is a few pounds lighter than the plastic box. We did a back to back on the dyno and the MAF’d CSL made a few more hp than the stock box. So I stayed with it.

His tune is excellent, btw. Very smooth linear power to redline. 336hp.

I believe he said the previous issues with the MAF were limitations in the torque tables. He’s figured out how to increase these in the ecu and make more power.

[Rombbb]

Originally Posted by Michael9218

Joshua (pokeybritches) is definitely the guy that needs to weigh in here.

Nice !

For me it's only about the intake sound. Car is fast enough for my capabilities :-)

Googling a bit further it appears there are several MAF carbon boxes.

This one looks pretty good as well, only USD 1350,-. German seller with seemingly good reviews. Only thing is that the ad mentions it's for LMM (Luft Masse Messer, Air Mass Meter) and on one pic from the engine bay it seems hooked up, but when looking at the standalone pics I dont see anywhere to plug in the MAF. Will have to ask about that.
And uncertainty with this one is that it's not really shown how the intake pipes protrude inwards, if at all.
But the guy has a lot of cool carbon pieces for sale. I guess the market for these is really picking up for youngtimers.

What do you think ?

I'm a layman and obviously quality is hard to gauge from pics (how well do those ITB connectors hold, is it fully air tight etc.) but at first glance I'd say it looks pretty good.

Eventuri is like USD 900,- here and that's more or less a fancy cone filter. This looks like it should make more decent noise (if indeed carbon resonates the intake air). Yes it's 450,- more than that, but like half of what the other carbon boxes cost. And it says in his ads that it's not el cheapo chinese (for what that's worth :-)

https://www.ebay.nl/itm/BMW-M3-E46-C...oAAOSwlV9WRYkU

[maupineda]

Originally Posted by Rombbb

EDIT : FOUND IT : looks pretty amazing and better price than the Evolve ��

http://store.motorsportsconcepts.com...3-z4m-maf.html

I had seen that link before but I could not find a review anywhere. I currently have a Karb airbox and Epic tune and the only drivability issue I have experienced is an odd hesitation around 3k that happens very rarely. I also lost the Cruise control and the ability to run VANOS tests in ISTA+, this is due to the ECU not being able to control the throttle as it is missing the MAF input, which is needed for the ECU to fully control engine throttle.

I have even entertained the idea of swapping the Karb for an eventuri setup to recover the MAF and have a more flexible setup.

I believe the MSS70 has the ability to integrate a MAP sensor, as it does the MSS65 ECU from the E9x M3, but no one has investigated the MSS70 fully.

[Rombbb]

Originally Posted by maupineda

I had seen that link before but I could not find a review anywhere.

Thanks. Had same concern. I did find one forum poster mentioning that it didn't fit properly, he was more or less warning others and that delivery took 2 months and company was zero responsive. Site and product look great but that's not comforting.

I found another one, probably going with this, for 1350,-. Let's say all fails I end up losing that instead of 3000,- from a company that is (for me) across the pond :

https://www.ebay.nl/itm/BMW-M3-E46-C...oAAOSwlV9WRYkU

On a related note; I never tested it but heard from seller that the speed limiter was removed on my z4mc so something was changed in the DME. The cruise control never worked. Your cc ceased with Alpha N, now I'm a bit worried I am actually unknowingly running an Alpha N tune :-)

Probably not, but do you know if there's a way to double check the type of ECU software installed ?

I have a cable and Deep OBD BMW app but not really sure what to look for to recognize Alpha N tune.

Car seems to run fine, no hesitations or anything, just CC not working.

[Michael9218]

I think Joshua will tell you that the orientation of the MAF is very important. Changing the size and shape of the MAF housing will change the airflow readings across the MAF filament.

That box listed above does away with the stock filter housing/MAF. Bad idea...

[Rombbb]

Originally Posted by Michael9218

I think Joshua will tell you that the orientation of the MAF is very important. Changing the size and shape of the MAF housing will change the airflow readings across the MAF filament.

That box listed above does away with the stock filter housing/MAF. Bad idea...

Yeah good point.

Actually still a bit on the fence because of that. Hence also my original question, what is the reason for lack of MAF in those wide open boxes. I also thought it could have to do with the MAF having to be in a narrower funnel to measure accurately, which would negate any gains from a wide open box.

I guess if the MAF is in a random place in a big box it could be in a lower pressure zone with the ECU thinking less air is passing by and over-leaning the mixture.

Maybe I'll take the gamble and just regularly check for overly black or white spark plugs.

The alternative, Alpha N tune also seems a very rudimentary way of determining fuel mixture as it only accounts for temp and pressure changes as an after thought.

Obviously best to keep it stock, or go with the Eventuri cone which keeps the MAF tube, but am just curious to the intake note it could make with a carbon box.

An alternative could be, if the diameters are equal, to cut of the protruding tube with the MAF connection from the stock air filter housing and position that in between the funnel end of the carbon airbox and a cone filter. Then the sensor environment and its readings should remain similar

(although the distance between MAF and cilinder would then be greater which probably is also a relevant factor in play)

[Rombbb]

Originally Posted by Michael9218

Joshua (pokeybritches) is definitely the guy that needs to weigh in here. I recently worked with him on

I was thinking, maybe your setup is the best from an OEM-Aftermarket balance perspective.

The MAF is still in its original place (I guess not only it's location in a funnel is needed for accurate mass readings but also its distance from the cilinders is relevant for the ECU's calculations) and the carbon I assume provides a nicer resonated sound. Especially when this setup is combined with the eventuri scoop.

May I ask where you got that box ?

[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.

IMHO, carbon airboxes are marketed because they are another means for aftermarket parts companies to generate revenue. It’s something else to sell, and they also get customers for a tune with the airbox. They offer bling and sound great… and because racecar. There’s nothing wrong with chasing cosmetics or sound, but I don’t think the performance claims can be backed up by independent testing. On Mike’s car we gained 2 whp with the carbon airbox versus stock airbox, which is near the margin of error on the dyno. His car is an expenses-be-damned build where we were looking to extract every bit of the power we could, so we went with the carbon airbox due to the slight 2 whp advantage. Don’t expect see anything like the 20 whp gains some manufacturers advertise with only a carbon airbox change. Much of the additional power comes from the optimized tuning, specifically the VANOS. We ended Mike’s dyno session at an independently verified 336 whp STD, which is VERY healthy considering he essentially has an unopened S54 on stock cams. And his car will perform reliably no matter the weather or track because he is using a MAF sensor with his carbon airbox.

Another car I tuned in Serbia is putting down around 350 whp (final numbers TBD) on the stock airbox, SS V1 stepped headers, and 288/280 cams. The engine in that car is otherwise unmodified. 350 whp is about 410 bhp- wild for a naturally aspirated 3.2 liter engine with only exhaust, cams, and tune. Its specific output is on par with a 991.2 GT3 RS. I will happily ‘change my tune’ if I come across data that shows I’m wrong, but at this time I don’t think the stock airbox or MAF sensor are holding much of anything back.

For reference, my 996 Turbo pushes 1.4 bar of boost. When I lift off the accelerator during gear changes, the turbos continue to spin and generate boost pressure against the now-closed throttle body. This would create a massive pressure spike. I use twin Bosch 710N diverter (bypass) valves, with 1-inch ID outlets, to almost instantly dump 1.4 bar of boost plus any excess pressure caused by the throttle body closing. The Z4M’s 3.5-inch MAF sensor housing has SIX TIMES as much cross-sectional area as the twin 1-inch diverter valves on my 996 Turbo combined, and the air transiting through the Z4M’s MAF sensor housing only needs to fill a partial vacuum rather than relieve a pressure spike of several atmospheres. I fail to see how a MAF sensor could be a restriction on the Z4M.

I think the lack of understanding of torque demand tuning and inability to defeat torque limiters are the reasons that alpha-n was pushed so hard in the past. That, and customers want the exclusivity that comes with having a car tuned like a non-street legal racecar, especially when it’s called something cool like ‘alpha-n’.

Regarding the desire to move to a MAP-based speed density mode with the ECU, my question is why? Why mess with a good setup? MAF-based tuning works well. MAP-based tuning would be a lot of work and require a special skillset to figure out- and to what end? I’m not sure what would be gained with a change to speed density.

Lastly, don’t arbitrarily add a MAF sensor to a carbon airbox and expect it to function like OEM. MAF sensors are EXTREMELY sensitive to minute changes. Really, any time anything in the intake tract is changed, the MAF sensor should be rescaled… but I don’t know any tuners that bother to properly scale the MAF sensor on MSS70 to coincide with intake changes. You can get away with minor changes on the Z4M since its closed-loop fueling logic is so good. You cannot get around diameter changes of the MAF sensor housing. A 1mm change in MAF sensor housing equates to about a 2.5% change in fueling. This is another reason I suggest leaving the stock airbox in place. MAF scaling takes a very long time to get right, and it’s expensive to perform on a dyno when you consider how long the Z4M takes to reflash.

[wdb]

^^^ Should be a sticky. I love the look of the carbon intakes on the S54 and was considering one for my car. No longer.

[Rombbb]

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 ...

Thanks so much for the answer !

Best learning moment of the year. People in the thread were right referring to you.

The following I couldn't have said better and is one of the reasons I had my reservations :

" That, and customers want the exclusivity that comes with having a car tuned like a non-street legal racecar, especially when it’s called something cool like ‘alpha-n’. "

Gonna digest and continue exploring. Hopefully will bring some business your way.

[Steeler]

Rombbb you can't go wrong with Josh. He knows what he is talking about.
100% recommend his expertise

[MBan]

Originally Posted by Michael9218

Joshua (pokeybritches) is definitely the guy that needs to weigh in here. I recently worked with him on a tune for my track car. I came to him wanting an alpha N tune for a recently purchased Turner CSL box. He convinced me to reconsider and stay with the MAF. So I decided to have the best of both and fabricated a panel that allowed the use of the MAF with the CSL box. I wanted to use the CSL box as it looked to have better shaped velocity stacks for high rpm and is a few pounds lighter than the plastic box. We did a back to back on the dyno and the MAF’d CSL made a few more hp than the stock box. So I stayed with it.

His tune is excellent, btw. Very smooth linear power to redline. 336hp.

I believe he said the previous issues with the MAF were limitations in the torque tables. He’s figured out how to increase these in the ecu and make more power.

Did you consider the Eventuri intake? There are a few independent dyno charts that show in the order of 10-12hp at the wheels. Not to say the path you went wasn't worth an experiment, just interested to hear your thoughts on why you went that way.

[Willy Sea]

There are other posts on this forum relating to Eventuri intakes. FWIW.

[MOTK]

Originally Posted by pokeybritches

Regarding the desire to move to a MAP-based speed density mode with the ECU, my question is why? Why mess with a good setup? MAF-based tuning works well. MAP-based tuning would be a lot of work and require a special skillset to figure out- and to what end? I’m not sure what would be gained with a change to speed density.

If the maf setup is so great why did bmw go to all the expense of going to a map setup for such a relatively small production run of the CSL?

[Michael9218]

Originally Posted by MBan

Did you consider the Eventuri intake? There are a few independent dyno charts that show in the order of 10-12hp at the wheels. Not to say the path you went wasn't worth an experiment, just interested to hear your thoughts on why you went that way.

I did consider it, but chose to get the Turner box and go alpha N for more power...that was the plan. Obviously that changed.

It would be interesting to add the filter arrangement from the eVenturi to this set up and see if it would make any more power.

I’m not convinced that airflow is a restriction to making power, though.

[1stw0rldpr0blems]

Originally Posted by Michael9218

Joshua (pokeybritches) is definitely the guy that needs to weigh in here. I recently worked with him on a tune for my track car. I came to him wanting an alpha N tune for a recently purchased Turner CSL box. He convinced me to reconsider and stay with the MAF. So I decided to have the best of both and fabricated a panel that allowed the use of the MAF with the CSL box. I wanted to use the CSL box as it looked to have better shaped velocity stacks for high rpm and is a few pounds lighter than the plastic box. We did a back to back on the dyno and the MAF’d CSL made a few more hp than the stock box. So I stayed with it.

His tune is excellent, btw. Very smooth linear power to redline. 336hp.

I believe he said the previous issues with the MAF were limitations in the torque tables. He’s figured out how to increase these in the ecu and make more power.

Is this setup still loud like a regular carbon airbox?

[Rombbb]

Originally Posted by Michael9218

I did consider it, but chose to get the Turner box and go alpha N for more power...that was the plan. Obviously that changed.

It would be interesting to add the filter arrangement from the eVenturi to this set up and see if it would make any more power.

I’m not convinced that airflow is a restriction to making power, though.

Was thinking about the combi as well; that would be a nice mix of stock MAF, carbon sound resonation and unrestrictive venturi effect filter.

Did you have that side carbon cover connecting the elbow custom made and you think the eventuri bolts on to it ?

If so I guess there will be more people interested in your setup (including me)

On a sidenote, in a sister thread on z4-forum someone noted that the different size of the box itself also influences the fuel-air mixture, which the MAF can't account for because the change is behind it. This would necessitate a tune anyways. Did you consider that factor in your setup ?

[pokeybritches]

Originally Posted by MOTK

If the maf setup is so great why did bmw go to all the expense of going to a map setup for such a relatively small production run of the CSL?

What would you gain with a MAP setup? Colder air into the engine? No. More airflow? Minimally. Looks/sound/exclusivity of a carbon intake in a package that's easier to incorporate? Yes. MAP setups are easier to dial in but less precise when it comes to emissions, which are not as big of a deal for a low production variant.

The carbon intake is worth about as much performance-wise as the carbon fiber roof IMHO. Why design special wheels, a carbon fiber trunk, lightweight plastics, etc.? Exclusivity is my guess. The CSL is a special edition model, and customers have been enamoured with the airbox since it was released, which has worked towards making the car extraordinarily desirable. BMW charged a whole lot more money for the CSL too, which was used to offset the low volume expenses.

BMW also got what... 17 more horsepower with CSL? This is with revised camshafts, different exhaust valves and manifolds, more aggressive tuning, and the holy grail carbon fiber intake manifold. Z4Ms with mods from the same categories (cams, exhaust, and tuning) are putting out 400+ horsepower with the stock airbox and MAF.

What modern exotic does not come with a MAF sensor?