CSL Airbox

[grannyknot]

Since there is so many experienced guys on this thread I would like to ask a related question.
How important is the air straightener in the stock filter box?
I have the aFe shroud, filter and Maf housing and it has no straightener of any kind, the induction sound is better for sure and regardless of aFe's claim of an additional 15 hp I don't think it really adds any extra power at all.
So just wondering if the straightening out of the the turbulent air makes a difference to power gain or Maf sensor accuracy.
Thanks

 

[TomK]

With my idea of routeing the standard grille air intake to the under side of the air box opening (ram air?), and try for some ducting to the front opening to direct air in the right direction (obviously no snorkel), then that should be as close as to the E46 CSL as possible.

I'm sure that would work well, hacking up the fang air ducts or bumper for a route to the airbox will be quite tricky though I think.

So just wondering if the straightening out of the the turbulent air makes a difference to power gain or Maf sensor accuracy.

I believe the standard airbox intentionally induces turbulent air in order to reduce induction noise. Your results makes sense.
The flap in the CSL box was also introduced for noise regs, the prototype CSL didn't have this flap.

 

[Justino]

I have just got round to removing the air filter housing - I probably should have done that before all my speculating!

I can see that actually there is little space and no obvious route for any additional airflow into this area other than the existing air duct which probably lines up with the snorkel opening, or that general direction.

That will leave the air box air feed on the underside - what have people done with this - just left it open -but then it will be sucking warm air, or put a hose on it so it sucks from lower down, or blanked it off? I cant see an obvious route to the lower fang area - I recall Vanne mentions this issue in one of his posts from a while back - didn't see a follow up for a solution.

 

[maupineda]

Regarding the Goke airbox, I wouldn’t worry about intake sizes.

The issue I have with this is that the standard Z4m airbox/filter housing has just the one air input that i can work out from the intake pipe that goes to behind the grille.

The CSL has the snorkel input routed to the bumper I assume, and also an input underneath the airbox, but not sure where this is routed too. In addition you also have the open mouth of the top section of the snorkel piece which on the CSL has the flaps in - so all in all a larger cross section of air input openings, 2 of which might be ram air.

The increased BHP of the CSL no doubt is down to the greater air input, so I am loathed to invest in a CSL intake, and then restrict it by just using the standard Z4M piping - the Goke box appears to me that it wouldn't give any extra air as its a sealed route to the existing input piping, therefore same air volume as a standard intake.

I am thinking that the air input underneath the CSL box, I connect if possible to the standard Z4M air pipe, and then somehow route airflow to the mouth of the box from another location, maybe lower grille area?

Be interested to get opinions?

The Z4M seems to have a feed that can connect to the lower air feed of the CSL box, just like the e46 M3. I do not know if the prior owner installed it, but it seems to be a factory item. so I have a Karb CSL airbox a modified snorkel plus the lower feed that collects air from the lower area behind the oil cooler.

I also have the RPI scoop to deflect some extra air to the airbox.

 

[PDJ]

Some thoughts
People talk about the ram air effect but how is this mapped for fuel on a rolling road
Engine bay temps when I have my Westfield I had a through the bonnet air filter but did some air temp readings from both inside and outside the bonnet and once moving they where almost the same I will do the same test with a twin probe temp meter when I have chance

Don’t know if it was the rules or not but I was told that when BMW race these cars they managed 400bhp with a standard air box

Again when I had my Westfield it was ticking over (2ltr Duratec) and the air filter was off I put my hand over one of the throttle body trumpets the result it hurt pulled the skin real hard so is there any real gain or the ram air effect

Suzuki had a ram air system on a few bikes but other did not follow

Just thoughts

 

[Justino]

The Z4M seems to have a feed that can connect to the lower air feed of the CSL box, just like the e46 M3. I do not know if the prior owner installed it, but it seems to be a factory item. so I have a Karb CSL airbox a modified snorkel plus the lower feed that collects air from the lower area behind the oil cooler.

I also have the RPI scoop to deflect some extra air to the airbox.

Be interested to see a picture of your pipe that connects to the unferside

 

[Justino]

Some thoughts
People talk about the ram air effect but how is this mapped for fuel on a rolling road

They use big fans was how I thought they created moving air.

 

[grannyknot]

So just wondering if the straightening out of the the turbulent air makes a difference to power gain or Maf sensor accuracy.

I believe the standard airbox intentionally induces turbulent air in order to reduce induction noise. Your results makes sense.
The flap in the CSL box was also introduced for noise regs, the prototype CSL didn't have this flap.

So you're saying the stock screen and plastic grid in front of it are there to tumble the air and not straighten it for the sake of the Maf sensor right next to it?

 

[PDJ]

Ŷ

They use big fans was how I thought they created moving air.

These are to cool the engine most rolling roads open the bonnet as well

The fans will not replicate 50mph or above

You would need to do some in car mapping on the road to get it right on different days to get as many variables smoothed out

I had to do this in my Westfield but even a full throttle run in second gear we ran out of road very quickly and it ends up the wrong side of the speed limit very quickly as well

An engine dyno cell is best but even the best can get in slightly out including BMW with the early M3’s ecu map

 

[TomK]

So you're saying the stock screen and plastic grid in front of it are there to tumble the air and not straighten it for the sake of the Maf sensor right next to it?

No, sorry. I believe it was the elbow on the way in to it before hitting the filter from what I remember reading about it.

You would need to do some in car mapping on the road to get it right on different days to get as many variables smoothed out

Agree, the ideal scenario is to hire out bruntingthorpe or something like that, it's the only way to really do it properly I think (actually not that expensive for an hour or so).
I'm interested in how much the ecu's can self adjust. I believe there's a barometric sensor on the mss70 board which might take care of one variable. The lambda sensors should help to avoid over-fuelling but are they not disabled on WOT or something like that?
I would hope that Martyn on here can chime in, certain he knows a lot more about this stuff than I do!

 

[TomK]

The Z4M seems to have a feed that can connect to the lower air feed of the CSL box, just like the e46 M3. I do not know if the prior owner installed it, but it seems to be a factory item.

This is quite interesting! Can you find reference to this on realoem or such? The few z4ms I've seen don't have this I'm pretty sure? Where is it drawing air from?

 

[TomK]

For interest perhaps here's how the goeke fits. Fwiw they have a pretty good reputation for engineering this stuff properly. The inlet track length and all sorts of other things well beyond my understanding are important in the design on any variation from the original / installation.

 

[maupineda]

The Z4M seems to have a feed that can connect to the lower air feed of the CSL box, just like the e46 M3. I do not know if the prior owner installed it, but it seems to be a factory item.

This is quite interesting! Can you find reference to this on realoem or such? The few z4ms I've seen don't have this I'm pretty sure? Where is it drawing air from?

I will take some photos tomorrow. Seems the part is not original to the car, but it is a BMW item and it attaches to a stud on the front rail. You can see this stud on your last photo above

 

[Martyn]

Agree, the ideal scenario is to hire out bruntingthorpe or something like that, it's the only way to really do it properly I think (actually not that expensive for an hour or so).
I'm interested in how much the ecu's can self adjust. I believe there's a barometric sensor on the mss70 board which might take care of one variable. The lambda sensors should help to avoid over-fuelling but are they not disabled on WOT or something like that?
I would hope that Martyn on here can chime in, certain he knows a lot more about this stuff than I do!

The Z4Ms ECU is actually pretty impressive when it comes to it's closed loop lambda control, which is active for the majority of the time, including at wide open throttle. The ECU will always aim to hit its pre-determined lambda setpoint, as part of this it looks at how much positive or negative trim it needs to apply to the base fuel map in order to hit that setpoint. The smaller the trim the ECU needs to apply, the happier the ECU will be.

 

[maupineda]

I took photos of how my car is set up. it seems the PO installed true CSL items.

This is a lower pipe that attaches to the framerail



The following is the "S" pipe that connects the lower pipe to the unfiltered section of the Karb box



The next two photos show the "S" pipe routed to the carbon airbox

 

[Justino]

I took photos of how my car is set up. it seems the PO installed true CSL items.

This is a lower pipe that attaches to the framerail

IMG_E3343.JPG

The following is the "S" pipe that connects the lower pipe to the unfiltered section of the Karb box

IMG_E3342.JPG

The next two photos show the "S" pipe routed to the carbon airbox

IMG_E3339.JPG

IMG_E3337.JPG

This is very helpful, thanks

The 2 first photos seem to show the CSL suction tube and air duct that go to the underside and connect to the carbon box - is that correct ? Both oe parts that will fit the Z4 engine bay it would seem. On realoem I cant see what the suction tube utlimately connects to or whether it dangles in free air.

The 3rd and 4th photos - do these connect to the existing Z4m input, and direct air to the open mouth area?

 

[Justino]

The suction tube connects to the long flexible pipe here

https://www.apmotorsport.co.uk/product-page/bmw-m3-csl-air-intake-parts-4pcs

That has a flared nozzle on it so helps 'catch' the air, but may not be needed for the Z - and at £298 is expensive anyway.

At a guess, your set up uses the other 3 parts shown.

 

[Justino]

For interest perhaps here's how the goeke fits. Fwiw they have a pretty good reputation for engineering this stuff properly. The inlet track length and all sorts of other things well beyond my understanding are important in the design on any variation from the original / installation.
DSC_0022.JPG
DSC_0021.JPG
DSC_0019.JPG

Its a very neat solution utilising the existing ram air feed.

The 2 things that are drawing me to the Karbonious set up are the design is more OE faithful/identical, and that there is still the opportunity to get more air into the box, which I think is one of the drivers for more power. I'm not necessarily looking for more power, but it seems worth pursuing if all it needs is some ducting etc.

I'm probably going to have to bite the bullet and buy the box, and figure out the pipework afterwards when I have it trial fitted.

 

[Justino]

The Z4M seems to have a feed that can connect to the lower air feed of the CSL box, just like the e46 M3. I do not know if the prior owner installed it, but it seems to be a factory item.

This is quite interesting! Can you find reference to this on realoem or such? The few z4ms I've seen don't have this I'm pretty sure? Where is it drawing air from?

Its part number 11617833646 and 11617833645 that I can make out on realoem. These ultimately connect to the CSL intake tube - but thats £298. This is a flexible (insulated) pipe that seems to be located to close to the air intake on the CSL bumper, but not connected. You can see it above the bumper intake here.

https://forums.m3cutters.co.uk/threads/karbonius-csl-airbox-complete-parts-list.140240/#post-1860609

The bumper intake goes to the snorkel.

 

[TomK]

or whether it dangles in free air.

I believe that's the case, it just draws air in from low in the engine bay in the csl application.