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

[maupineda]

Originally Posted by pokeybritches

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?

100% agree, most of the gains in fact came from the cams and engine mapping. The CSL airbox is really awesome from a sound and looks point of view though. I also think BMW had to go with a MAP setup as a way to balance off the whole package to not go to a complete close loop setup as alpha-n, plus this was in a time where emissions were not as tight.

[pokeybritches]

Originally Posted by Rombbb

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 ?

That assessment is not exactly correct. All air that enters the engine must pass through the MAF, regardless of the size of the airbox. So, the ECU accounts for the air through MAF readings. There may be some small discrepencies which could be tuned for via a MAF rescale, but most tuners would allow the fuel trims to take care of small variations rather than go through the effort of a MAF rescale.

A MAF rescale really should be done on an eddy current dyno, since fuel trims are historical artifacts, and tuners must account for what is known as a "transport delay"- the difference in time between combustion and for the lambda value to be reflected by the oxygen sensor. By holding the engine under constant load, part- and full-throttle, the effect of this delay can be minimized so that the tuner can properly rescale the MAF sensor.

Even without a rescale, a MAF-based tune is usually better than alpha-n.

[86Zed]

Great information pokeybritches and reinforcing what other have told me; CSL airbox funds are better spent elsewhere (3.9/4.1 final drive) if an improved driving experience is your goal.

If a mean looking engine bay and induction sound is your goal, all for it too!

[Rombbb]

Originally Posted by pokeybritches

There may be some small discrepencies which could be tuned for via a MAF rescale, but most tuners would allow the fuel trims to take care of small variations rather than go through the effort of a MAF rescale.

Good news, what I hoped for. As long as the box is somewhat similar and the MAF is in the same housing in the same position from the cilinders any fueling discrepancies due to different volume and shape of the box (and resulting pressure differences) are quite marginal.

Michael9218's solution seems a good trade off, especially when combined with Eventuri.

[pokeybritches]

When the intake valves open and air from the intake manifold begins to fill a cylinder, more air is pulled past the MAF sensor to fill the partial vacuum in the intake manifold just as it's being created. This happens faster than the speed of sound.

As precise as we like to be, combustion is ultimately a chaotic process. We have manufacturing tolerances in sensors, injectors, and systems. If you had your fuel injectors dynamically flow tested, they would vary in output by a few percent, and the latency and dead times would be different across all six. Oxygen sensors read differently as they age. The 1's and 0's in the ECU that model these systems are "close"... sometimes best average, and other times safest guess. In this case, I wouldn't overthink it.

I do think there is something to be said for intake manifold design in terms of taking advantage of pressure waves to increase power. As the intake valves slam shut, the air that was entering the cylinder piles up in front of the valve and forms a pressure wave that reflects back through the intake runner. By timing the intake valve opening at exactly the right time when the high pressure wave returns, the cylinder can be filled to a greater degree, and VE can exceed 100%. I'm not going to say the OEM design is the absolute best design there is, but I wouldn't discount the effect that intake manifold tuning can have on the performance characteristics of the engine. In other words, the intake manifold needs to be more than just a box made out of carbon fiber. Some are better than others.

Finally, I don't necessarily dislike carbon intakes. They sound and look fantastic. I just want to dispell some myths about alpha-n and MAF-based tuning.

[Rombbb]

Originally Posted by pokeybritches

When the intake valves open and air from the intake manifold begins to fill a cylinder

Nice, thanks. Interesting topic.

Am close to biting the bullet with a german manufacturer, example in bottom left pic, https://www.vft-opitz.de/galerie.
" several layers of carbon, vacuum RTM process with tempering, milled aluminum connections, corresponding to series. " For USD 1350,-

MAF housing will be circular with 90mm inner and 94mm outer diameter. So bigger than OEM (according to him, I didn't measure it yet) but he seems reliable and claims years of experience and stated that Motronic will adapt.

It remains a bit of a gamble, especially considering all your info, but probably I'll take the chance.

Is it possible that when installed I send you over some ECU log files or something so you can get a feel for the mixture ? (for payment of course)

Just to check that it doesn't suddenly run super lean or rich.

[David70]

Originally Posted by pokeybritches

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.

I appreciate the information. The above has me not interested in moving forward with a carbon intake as I can't see the money spent being worth what seems to be only a noise box.

[RossBMWZseries]

Thanks for all the input Josh. I’ve always read that other than providing great engine sound and looks, the airbox actually was a nice little upgrade for power. Am I interpreting this the wrong way where there’s not much to gain going the airbox route with an alpha N tune?

Also, what are the pros and cons (if any cons), of going with the Alpha N vs a tune you can provide us guys that wanna keep the airbox?

[MBan]

Originally Posted by Rombbb

Nice, thanks. Interesting topic.

Am close to biting the bullet with a german manufacturer, example in bottom left pic, https://www.vft-opitz.de/galerie.
" several layers of carbon, vacuum RTM process with tempering, milled aluminum connections, corresponding to series. " For USD 1350,-

MAF housing will be circular with 90mm inner and 94mm outer diameter. So bigger than OEM (according to him, I didn't measure it yet) but he seems reliable and claims years of experience and stated that Motronic will adapt.

It remains a bit of a gamble, especially considering all your info, but probably I'll take the chance.

Is it possible that when installed I send you over some ECU log files or something so you can get a feel for the mixture ? (for payment of course)

Just to check that it doesn't suddenly run super lean or rich.

Rombbb

Did you end up going ahead with this?

I was watching a Youtube video about the Redux E30 M3 and it was amazing how good the carbon intake sounded (on a 4-cylinder too)... which inevitably got me thinking about carbon airbox options again.

A few people in this thread have said they would prefer to spend their money on other things given the CSL-style intake is mostly for looks and sound, but I wonder if there would be interest in having an exact reproduction of the stock plenum made in CF? Evolve/Eventuri do it for the E9X M3, which sounds amazing. I'm sure Karbonius could make it too.

You could add an Eventuri, Gruppe M or leave the airbox stock, no problem with the MAF and you should(?) get the amazing CSL warble.

[Bmwdude33]

It’s always cool factor and sound. That’s the motivation behind most things in life.

[maupineda]

Originally Posted by MBan

Rombbb

Did you end up going ahead with this?

I was watching a Youtube video about the Redux E30 M3 and it was amazing how good the carbon intake sounded (on a 4-cylinder too)... which inevitably got me thinking about carbon airbox options again.

A few people in this thread have said they would prefer to spend their money on other things given the CSL-style intake is mostly for looks and sound, but I wonder if there would be interest in having an exact reproduction of the stock plenum made in CF? Evolve/Eventuri do it for the E9X M3, which sounds amazing. I'm sure Karbonius could make it too.

You could add an Eventuri, Gruppe M or leave the airbox stock, no problem with the MAF and you should(?) get the amazing CSL warble.

I very likely would swap my Karb for something like this.

[MBan]

Originally Posted by maupineda

I very likely would swap my Karb for something like this.

I think I'll look into it after finishing my suspension upgrade. Ticks pretty much all the boxes for me.

[grannyknot]

Originally Posted by maupineda

I very likely would swap my Karb for something like this.

Originally Posted by MBan

I think I'll look into it after finishing my suspension upgrade. Ticks pretty much all the boxes for me.

I have just emailed VFT-Verbundfastertechnick asking what the chances of them producing a carbon fiber stock airbox with MAF for the S54, I'm sure there are many of us with E46/M3's and E86/Z4M's who would be interested in this kind of a setup. Even a one time group buy would be good.
Fingers crossed.

[Westersund]

I don't have a CSL box in my Z4 M, but I do have one in my E46 M3 race car and it makes 320.6 WHP. It's a US car but the headers are changed to Euro ones and it has a standalone ECU (MaxxECU). Quite a bump from stock with only Euro headers (The car is cat-less) and a CSL box. The gain could be credited mainly to the cat-delete and a good tune though, but it does sound glorious.

[AriuSen]

I can assure any car will feel much worse than what the dyno numbers showed.

Airbox and alpha N are a gimmick unless you have a live tuner at each track.

[MBan]

Originally Posted by grannyknot

I have just emailed VFT-Verbundfastertechnick asking what the chances of them producing a carbon fiber stock airbox with MAF for the S54, I'm sure there are many of us with E46/M3's and E86/Z4M's who would be interested in this kind of a setup. Even a one time group buy would be good.
Fingers crossed.

Thanks, grannyknot. Very interested to hear about the response you get.

I haven't heard of VFT before - have you worked with them on other custom CF projects?

[grannyknot]

Originally Posted by MBan

Thanks, grannyknot. Very interested to hear about the response you get.

I haven't heard of VFT before - have you worked with them on other custom CF projects?

No I haven't, I just heard about them when Rombbb mentioned them above. So far I haven't had any reply from them, their website is all in German but contact info is in English so I have to assume they will deal with us in North America.

[wdb]

Originally Posted by grannyknot

No I haven't, I just heard about them when Rombbb mentioned them above. So far I haven't had any reply from them, their website is all in German but contact info is in English so I have to assume they will deal with us in North America.

Hey -- euros is euros. Count one more interested party.

[MBan]

Originally Posted by grannyknot

No I haven't, I just heard about them when Rombbb mentioned them above. So far I haven't had any reply from them, their website is all in German but contact info is in English so I have to assume they will deal with us in North America.

Ahh, thanks. I thought these guys well known and it was just me that hadn't heard of them!

If these guys don't reply, maybe we could convince Evolve or Karbonius. One way or another, it isn't going to be cheap, but I'm keen to see if it's doable.

[Vanne]

hmm.. lots of info in this thread, good info.. I would like to remind people that spending /any/cash on bolt ons isnt going to net huge numbers, everything is a trade off, and sadly our s54 don't respond well in comparison to non NA engines. you can gain a few HP in the topend, in tradeoff to loosing torque in the bottom end. its a tradeoff. everything is a tradeoff..

I did love the sound that the CSL intake made on the S54, that sound was intoxicating, and unless you had/have a combination of add up mods to go with that intake, i am sure your loosing a hell of a lotta torque down low. (no doubt what Alex is saying)

Does it matter? unless your racing? probably not...

just to quickly add up a few numbers

S54 powered Z4M, no idea, lets say 30K.. Thats probably a bit much, but bear with me..

CSL intake and supporting mods.. 5k
Cams and install 4K
Exhaust and install 2k

thats already 35 percent of the cost of the car, with no real clear indication of how much extra HP/Torque your getting.. sadly thats just the truth with the NA S54.. its a lot of cash, for really lets be real here, maybe 35HP extra? )
(and thats complimenting add/on/bolt ons) each of those by itself (cams aside maybe) could even be a drop in performance...

whats the answer?

Beats the shit outa me?, seems that we have a real nice engine already, and with a tune (thanks Josh), it might just be the best it can get unless your in over your head and are spending HUGE dollars. Why I am I telling you this? because I want you to be aware that throwing a shit load of dollars at the S54 isnt going to net you hardly any (in comparison to other engines) increase in performance. thats just the way it is..

but that CSL intake sure as hell does sound the goods

Happy new years everyone

[grannyknot]

Originally Posted by grannyknot

I have just emailed VFT-Verbundfastertechnick asking what the chances of them producing a carbon fiber stock airbox with MAF for the S54, I'm sure there are many of us with E46/M3's and E86/Z4M's who would be interested in this kind of a setup. Even a one time group buy would be good.
Fingers crossed.

So I did get a response from them but they just pointed me to their one piece box they sell on ebay, https://www.ebay.com/itm/234073327283

[MBan]

Originally Posted by grannyknot

So I did get a response from them but they just pointed me to their one piece box they sell on ebay, https://www.ebay.com/itm/234073327283

Thanks for checking. I'll send Eventuri an email and see what they say.