Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

CSL Airbox

"M" Specific discussion
Justino
Member
Member
Posts: 191
Joined: Mon May 28, 2012 11:08 pm

CSL Airbox

Post by Justino » Sun Oct 02, 2022 10:32 am

beanie wrote: Tue Sep 27, 2022 9:51 pm 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?
2008 Z4MR Silver Grey
2017 Audi A6 Avant Quattro 3.0 BiTdi
2003 Clio 172 Cup

NLW73
Member
Member
Posts: 121
Joined: Sun Jan 23, 2022 8:10 pm

CSL Airbox

Post by NLW73 » Sun Oct 02, 2022 10:43 am

CSL had the different cams with a higher profile and a different map I think so combined with the additional air coming in through the giant intake that would add up to the small gains. and 200 cell cats from OEM so that will help with breathing.

beanie
Member
Member
Posts: 834
Joined: Sun Aug 05, 2012 9:57 pm
Location: Bournemouth/Turin

CSL Airbox

Post by beanie » Sun Oct 02, 2022 11:25 am

If, and it’s definitely an ‘if’, there is a restriction in the inlet, then it’ll be the MAF housing. Obviously all airboxes do away with this so you’ll reduce restriction whichever you choose. There’s no doubt bmw will have researched and engineered things properly, far better than any aftermarket company, however, unless you’re pushing the envelope in terms of power then I truly believe all the mafless airboxes will be pretty much identical in the real world.

As NLW73 said, the csl had different cams and also larger exhaust valves. Still, the Goke still seems to allow for gains with more aggressive cams so whilst the theory of restriction seems sound on paper, it appears it’s no issue even with a decently tuned S54.

I’m not trying to push you in any direction but just putting it out there that you’re unlikely to run in to an issue with the Goke. FWIW, if I was buying an airbox today, I’d probably go with a karbonius simply because it looks most like the original. If the budget was a bit tighter I’d have no issue fitting a GSR box.

Whichever you go for, the added horsepower will pail into insignificance compared to the sound they all produce. 10,20hp isn’t life changing but the induction noise really is! :D
Image
RUBYIMOLACARBON

User avatar
TomK
Senior Member
Senior Member
Posts: 2363
Joined: Fri Jan 25, 2013 11:50 pm
Location: West London

CSL Airbox

Post by TomK » Sun Oct 02, 2022 12:01 pm

My two cents having opted for the Goke version.
Personally I don't think that the diameter of the air intake is as important as the speed and temperature of the air reaching the trumpets. In this regard the idea of taking the air directly from the front of the car is superior in my eyes to that of taking air in from the engine bay.
The RAM air affect that the CSL uses (and I assume the z4 (I also have an RPI sccop)) is quite important to the workings of it. As the car picks up speed, air with higher velocity enters the ram air intake in the front bumper which is sent to the intake.
The air is colder and with speed (instead of the typical NA engine behaviour of having to suck air, you send air with pressure).
More air, colder air + Alpha-N = more HP.
I also think the original CSL ducting design is slightly compromised, not surprising when they had to repackage the front end. A lot of E46 M3 race cars take air in from a modified headlight ducting straight to the mouth of the CSL box.
When I had my car mapped and dynoed, my friend had his m3 with CSL box also mapped there the next day, so same dyno/operator/atmospheric conditions. Mine had 288/80 cams and made 384bhp, his with standard cams made 353. I don't care about the absolute numbers but cams do not give 30bhp and whilst there are of course lots of other variables I think it is safe to say that the size of the original Z4 intake hole is not a restriction worth noting imo.
As Beanie says, whichever route you go it's really just the noise that's important!
MC[IB], CSL airbox, Schrick 288/280 cams, 4.44FD, UUC SSK, SS race cat back, AP CP9660[F]/5144[R] brakes, Apex ARC-8 with AR-1 or PS5, KW ClubSport 2-way, Turner spherical arms, PMC uniball rtab, VB engine mounts, Rogue pulleys & RSMs, Tillett B6, half cage

Justino
Member
Member
Posts: 191
Joined: Mon May 28, 2012 11:08 pm

CSL Airbox

Post by Justino » Sun Oct 02, 2022 1:24 pm

Thanks for the input guys.

I am leaning towards the Karbonius for the reason you suggest - looks more OE, just need to decide which finish to have 2x2 Twill, or plain, then matt or gloss. I know its not OE, but like the idea of the matt finish, but not sure which weave is most OE.

I get what you say about the air, but as I haven't pulled the trigger yet, I just wanted to consider all the options, and now is the best time to try and figure it out.

My logic is the E46 has 2 ducts to the air box, underside (ram air?) and to the snorkel, plus the open end when the flap open with some ducting by the slam panel that directs air to that location, so that's quite a bit more than the Z4, which just has the one ram air.

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.
2008 Z4MR Silver Grey
2017 Audi A6 Avant Quattro 3.0 BiTdi
2003 Clio 172 Cup

User avatar
grannyknot
Member
Member
Posts: 412
Joined: Sat Oct 23, 2021 1:18 pm

CSL Airbox

Post by grannyknot » Sun Oct 02, 2022 1:56 pm

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
IMG_0143.JPG
IMG_0143.JPG (169.46 KiB) Viewed 747 times
IMG_1159.JPG
IMG_1159.JPG (139.18 KiB) Viewed 747 times
2008 E86 M coupe
Toronto, Ontario

User avatar
TomK
Senior Member
Senior Member
Posts: 2363
Joined: Fri Jan 25, 2013 11:50 pm
Location: West London

CSL Airbox

Post by TomK » Sun Oct 02, 2022 2:09 pm

Justino wrote: Sun Oct 02, 2022 1:24 pm 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.
grannyknot wrote: Sun Oct 02, 2022 1:56 pm 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.
MC[IB], CSL airbox, Schrick 288/280 cams, 4.44FD, UUC SSK, SS race cat back, AP CP9660[F]/5144[R] brakes, Apex ARC-8 with AR-1 or PS5, KW ClubSport 2-way, Turner spherical arms, PMC uniball rtab, VB engine mounts, Rogue pulleys & RSMs, Tillett B6, half cage

Justino
Member
Member
Posts: 191
Joined: Mon May 28, 2012 11:08 pm

CSL Airbox

Post by Justino » Sun Oct 02, 2022 5:31 pm

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.
2008 Z4MR Silver Grey
2017 Audi A6 Avant Quattro 3.0 BiTdi
2003 Clio 172 Cup

maupineda
Member
Member
Posts: 139
Joined: Fri Apr 24, 2020 4:46 pm

CSL Airbox

Post by maupineda » Sun Oct 02, 2022 6:22 pm

Justino wrote: Sun Oct 02, 2022 10:32 am
beanie wrote: Tue Sep 27, 2022 9:51 pm 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.
Attachments
IMG_0045.JPG
IMG_0045.JPG (181.92 KiB) Viewed 700 times
20190825_120358.jpg
20190825_120358.jpg (233.45 KiB) Viewed 700 times

PDJ
Senior Member
Senior Member
Posts: 1101
Joined: Sun May 13, 2018 10:32 am
Location: Worsley Manchester

CSL Airbox

Post by PDJ » Sun Oct 02, 2022 8:36 pm

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
Member
Member
Posts: 191
Joined: Mon May 28, 2012 11:08 pm

CSL Airbox

Post by Justino » Sun Oct 02, 2022 9:51 pm

maupineda wrote: Sun Oct 02, 2022 6:22 pm 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
2008 Z4MR Silver Grey
2017 Audi A6 Avant Quattro 3.0 BiTdi
2003 Clio 172 Cup

Justino
Member
Member
Posts: 191
Joined: Mon May 28, 2012 11:08 pm

CSL Airbox

Post by Justino » Sun Oct 02, 2022 9:53 pm

PDJ wrote: Sun Oct 02, 2022 8:36 pm 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.
2008 Z4MR Silver Grey
2017 Audi A6 Avant Quattro 3.0 BiTdi
2003 Clio 172 Cup

User avatar
grannyknot
Member
Member
Posts: 412
Joined: Sat Oct 23, 2021 1:18 pm

CSL Airbox

Post by grannyknot » Sun Oct 02, 2022 10:07 pm

TomK wrote: Sun Oct 02, 2022 2:09 pm
grannyknot wrote: Sun Oct 02, 2022 1:56 pm 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?
2008 E86 M coupe
Toronto, Ontario

PDJ
Senior Member
Senior Member
Posts: 1101
Joined: Sun May 13, 2018 10:32 am
Location: Worsley Manchester

CSL Airbox

Post by PDJ » Mon Oct 03, 2022 10:02 am

Ŷ
Justino wrote: Sun Oct 02, 2022 9:53 pm 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

User avatar
TomK
Senior Member
Senior Member
Posts: 2363
Joined: Fri Jan 25, 2013 11:50 pm
Location: West London

CSL Airbox

Post by TomK » Mon Oct 03, 2022 11:35 pm

grannyknot wrote: Sun Oct 02, 2022 10:07 pm 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.
PDJ wrote: Mon Oct 03, 2022 10:02 am 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!
MC[IB], CSL airbox, Schrick 288/280 cams, 4.44FD, UUC SSK, SS race cat back, AP CP9660[F]/5144[R] brakes, Apex ARC-8 with AR-1 or PS5, KW ClubSport 2-way, Turner spherical arms, PMC uniball rtab, VB engine mounts, Rogue pulleys & RSMs, Tillett B6, half cage

Post Reply