S50 airbox questions

[m3f_bmwstephen]

So I just bought a stock airbox to replace the aftermarket one the PO installed. While cleaning it, I noticed two unusual things that I was hoping someone with a stock airbox can clarify for me.



1) Next to the snorkel socket, there is a small hole on mine. It doesn't look drilled but at the same time it doesn't look like a clean cut. Is this from the factory?





2) Regarding the actual Snorkel piece's opening, there seems to be a rotating piece of broken plastic clipped onto a rod in the center. What is that broken piece for?

[m3f_M3AN]

That doesn't look like my stock s50b32 airbox or snorkel, what exactly is it off do you know?



Mine has multiple components:



Airbox

Snorkel from kidney grill to airbox that also has an "arm" down to the brake duct (blanked off from factory)

Brake duct with outlet to alternator cooling snorkel and blanked off hole to mate with previously mentioned "arm" (which I've now opened and connected to said arm)



I don't recall seeing that rotating bit but will have another look... Which piece/end is it on?

[m3f_bmwstephen]

That doesn't look like my stock s50b32 airbox or snorkel, what exactly is it off do you know?



Mine has multiple components:



Airbox

Snorkel from kidney grill to airbox that also has an "arm" down to the brake duct (blanked off from factory)

Brake duct with outlet to alternator cooling snorkel and blanked off hole to mate with previously mentioned "arm" (which I've now opened and connected to said arm)



I don't recall seeing that rotating bit but will have another look... Which piece/end is it on?

sorry. I should've been more clear. This is for an s50b30 USA spec'ed motor. That's why there's a big difference in intake design

[m3f_M3AN]

sorry. I should've been more clear. This is for an s50b30 USA spec'ed motor. That's why there's a big difference in intake design

Oh, I see.



They really should have called that the S52B30...

[m3f_blizzard424]

That looks like my S52 air box. It has the same hole there. Not really thinking about it, I put a piece of tape over it. The clip you have there snaps into the bracket behind the kidney grill. It's probably not absolutely necessary because the snorkel gets wedged in there pretty good as it is.

[m3f_bmwstephen]

Great thanks for verifying. I just wanted to make sure it was factory and not damage

[m3f_twentyseven]

Pretty sure that is a drain hole for any water or moisture, and the clip secures the snorkel to the radiator support.

[m3f_M_Parallel]

Oh, I see.


They really should have called that the S52B30...

Actually not. The US M3 3.0 was also named S50, full name being S50B30US


That's why this is always confusing.


p.s. On the EU S50B32 the the appendix on the airbox going to the breakduct is blanked off (I haven't seen if it is just a dead end or just not connected to the airbox, but open. So I wonder if connecting it would give too much air and upset the stock setup.


I was also surprised to see the S50B32 doesn't have alternator cooling like the 3.0 has.


Did you fit the entire 3.0 setup? Did it just fit? I thought maybe fitment issues made BMW decide to not fit it.

[m3f_M3AN]

p.s. On the EU S50B32 the the appendix on the airbox going to the breakduct is blanked off (I haven't seen if it is just a dead end or just not connected to the airbox, but open. So I wonder if connecting it would give too much air and upset the stock setup.



I was also surprised to see the S50B32 doesn't have alternator cooling like the 3.0 has.



Did you fit the entire 3.0 setup? Did it just fit? I thought maybe fitment issues made BMW decide to not fit it.

Actually my early (7/96) S50B32 does have the alternator cooling, my friends 6/97 does not. I'll have to check if they're the same alternator. Perhaps the extra cooling was determined to be unnecessary?



The brake duct appendage is actually part of the snorkel, not the airbox and it's blanked off on both the snorkel and the brake duct from the factory. I've modified mine and connected them up, you can't have too much air!

[m3f_blizzard424]

That looks like my S52 air box. It has the same hole there. Not really thinking about it, I put a piece of tape over it.

Following up on the hole, someone on another thread commented that part 13711289624 goes there so the airbox isn't resting on the chassis rail.

[m3f_M_Parallel]

Actually my early (7/96) S50B32 does have the alternator cooling, my friends 6/97 does not. I'll have to check if they're the same alternator. Perhaps the extra cooling was determined to be unnecessary?



The brake duct appendage is actually part of the snorkel, not the airbox and it's blanked off on both the snorkel and the brake duct from the factory. I've modified mine and connected them up, you can't have too much air!

Ha yes, I used incorrect wording. It's of course the snorkel, not the airbox itself.



So it's blanked off. That would make it more like a resonance chamber if anything.



What does make me wonder if it extends all the way down to the brakeduct. As in, could I just cut it open on the snorkel and the brakeduct hole and just connect them. I have a feeling it doesn't even go all the way down to the duct.



My M3 is from 3/98. Rechecking the parts catalog I now notice the alternator cooling is listed as up to 12/96. So that about explains it all.



Do wonder if there is any technical reasoning behind it. My alternator housing doesn't even have a snorkel, so even if I would buy the ducting, I have nothing to connect it to.

[m3f_M3AN]

What does make me wonder if it extends all the way down to the brakeduct. As in, could I just cut it open on the snorkel and the brakeduct hole and just connect them. I have a feeling it doesn't even go all the way down to the duct.

They almost touch, will post some pics when I get to my computer.


Edit: Here's my modification.

[m3f_bmwstephen]

Following up on the hole, someone on another thread commented that part 13711289624 goes there so the airbox isn't resting on the chassis rail.

okay after fiddling with it some more, it looks like the rubber piece is to be inserted into a different area of the intake. I just don't see how that rubber buffer is mounted into that small hole. Thoughts??



Here's a new pic with the angle of the hole. This the angle as if the box were mounted in the engine bay.

[m3f_M_Parallel]

There is no rubber buffer there. There is a big half-circle buffer on the inside of the fender where the "foot" of the airbox rests on.



Did the US airbox get the heatshield? All I can think of is that it's the hole where a threaded metal piece goes into where the hieldshiel is mounted on.



Here's the inner fender buffer:







And here's where the heatshield fixes to the side of the airbox

[m3f_blizzard424]

I've never seen an OEM heat shield like that, and I can't seem to find it in realoem for US or Euro models.