New Airbox

fmorelli

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Aug 11, 2017
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Thanks to my good friend, @Seb335i, who brought this to my attention. @NoQuarter and I have been discussing alternate intake solutions for a while, with @NoQuarter leveraging work @BQTuning began some time back. Most people that have addressed this issue, have done so crudely, with DCI solutions pulling dirty air from the engine compartment. We had been looking at feeding clean air from alternate locations to a modified N54 740i box. If you consider that BMW has real engineers that design the engine system end to end, it should be pretty obvious to know that requiring 2x the air (for 2x the power) well exceeds what the stock system is designed to deliver without exceptional resistance.

So this is pretty cool:

Revdrop Airbox: https://revdop.de/produkt/bmw-n54-luftfilterkasten/

Technical forum discussion: http://bimmertech.de/forum/forum/n5...ativen-druckverlustminimalen-luftfilterkasten

Discussion with the designer:

Filippo
 
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impuls

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Jan 28, 2018
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The airbox was released two years ago. It is not in stock right now. Based on the fact there was a clearance sale 1.5 years ago, I doubt it will be back in stock ever.

It is also strange how they brag about how well this box is engineered and then not publish flow numbers.
 

derekgates

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Feb 23, 2018
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That looks great!

I upgraded my airbox using the Z4 35is lid, which BuraQ talks in one of his posts about flow being restricted on the N54 335i due to packaging limits (the cowl). With the M3 cowl I was able to fit the much higher flow lid on my car.

IMG_1444.JPEG
IMG_1448.JPEG
IMG_1447.JPEG
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I still long for the 7 series air box with custom inlets for the turbos, but this makes setup removes much of the DCI downsides and is *far* quieter than the noisy cones. :)
 

ShocknAwe

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Jan 24, 2018
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I should also mention Hydra's intake which is a hybrid short front inlet with cone filter and long rear stock location inlet with aFe Momentum GT airbox hooked up to the stock snorkel.

Hard to jam a big enough inlet in there to get to the front for a box. I'd love to have a dual ram box.
 

fmorelli

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We've done some measurements of cross-section and determined that the stock configuration is restrictive at higher airflow needs. The DCI's pull in dirty air, which is not my preference (and unfortunately what is on my car at the moment, though that will change). @BQTuning did some testing with thermocouples back in the day, which was also insightful. Glad to hear your setup is working well for you! Stock airbox is a win.

BTW great reference on the Mr 5 intake ... I'd not seen this write-up and will read it when I can sit and digest, but first blush looks interesting. Ironically this looks similar to what @NoQuarter and I have been discussing. Glad to see there is an actual example in use and documented!

Filippo
 

derekgates

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Feb 23, 2018
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2011 335is
We've done some measurements of cross-section and determined that the stock configuration is restrictive at higher airflow needs. The DCI's pull in dirty air, which is not my preference (and unfortunately what is on my car at the moment, though that will change). @BQTuning did some testing with thermocouples back in the day, which was also insightful. Glad to hear your setup is working well for you! Stock airbox is a win.

BTW great reference on the Mr 5 intake ... I'd not seen this write-up and will read it when I can sit and digest, but first blush looks interesting. Ironically this looks similar to what @NoQuarter and I have been discussing. Glad to see there is an actual example in use and documented!

Filippo

Ah yes, I tried my hardest to install a Mr5 Intake with my car. I have all the parts in my garage for the setup including a K&N Apollo inline filter. Unfortunately I was unable to route the intake 'hose' into my bumper as the PPK and DCT cooler is in the way completely. Bummer.

https://www.e90post.com/forums/showthread.php?p=8762970 this was the thread I modeled my attempt after

I also wrote up an Evernote with a bunch of links to different Mr5 Intakes:

Not always recommended to use DCI due to engine temps affecting air density. DCI setup flows more than stock airbox but air is ingested after radiator.

Mr5 Intake adds an extra intake and cone to the unfiltered side of the airbox; allowing air to be pulled in from the lower bumper area.

Additions were made to the original design to use a smooth flowing flange, using a K&N Apollo setup (instead of filter in bumper area), etc.


Guides/DIYs

https://www.e90post.com/forums/showpost.php?p=11735900&postcount=1 - BQ review
https://www.e90post.com/forums/showpost.php?p=11744875&postcount=14 - BQ review
https://www.e90post.com/forums/showpost.php?p=11800831&postcount=80 - BQ review
https://www.e90post.com/forums/showpost.php?p=12242787&postcount=26 - BQ review
https://www.e90post.com/forums/showthread.php?t=1223038
https://www.e90post.com/forums/showthread.php?t=169169
https://e89.zpost.com/forums/showthread.php?t=1403666 - BQ New intake prelue

Parts Needed
  • Airbox
  • 2.75” OD flange (Aluminum duct flanges?)
  • K&N Apollo cold air intake (includes cold air feed hose with velocity stack and adapter to the intake box). It costs $127 online.
  • 2 x 2.75" 90 degrees silicone couplers (or reinforced tubing from McMaster Carr?)
  • 1 silicone joiner
  • 4 hose clamps
  • Custom rubber gasket for the intake flange
  • K&N air filter sealing grease (to properly seal the gasket to the intake flange and airbox)
  • 2.75" hole saw and power drill
  • Injen power steering relocation bracket to make room for the K&N Apollo filter (I think it may work without it but I am not sure)

Relocating PS reservoir
E82/E92/E93 Driver Side Power Steering Tank Brackets
X-20088- 358i Steel Power Steering Cup Relocating Bracket


http://www.e90post.com/forums/showpost.php?p=9550455&postcount=62
The PS fluid reservoir relocation was a fun bit.

1) un-mount the PS fluid reservoir
2) remove the big steel bracket that bolts to the front frame
3) remove the mounting bracket from the reservoir
4) replace the mounting bracket upside down on the reservoir, above the lip to better clear the hood (I also put a little high-temp double-sided tape inside the bracket's ring to keep the reservoir from slipping out of the bracket)
5) fabricate a small, stainless, 45-degree angled bracket to mount the reservoir bracket to on the little nub behind the headlights
6) remount the reservoir to the nub+stainless bracket

With the above steps, there's a ton of room for the 3" ID hose to my cone filter in the fender.
 

impuls

Specialist
Jan 28, 2018
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'07 335i
Wonder if the 335d airbox could be used instead of the cone intake when doing a @Hydra Performance style intake.

Anybody keen to preserve OEM look thought about that?
 

dcafs

New Member
Apr 27, 2019
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2008 135i
That looks great!

I upgraded my airbox using the Z4 35is lid, which BuraQ talks in one of his posts about flow being restricted on the N54 335i due to packaging limits (the cowl). With the M3 cowl I was able to fit the much higher flow lid on my car.

So are you saying the Z4 lid will not fit under a standard 335 or 135 stock cowl?
 

E92 420

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Jul 8, 2017
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So are you saying the Z4 lid will not fit under a standard 335 or 135 stock cowl?
Z4 lid fits fine under stock cowl I ran the z4 lid and mr5 airbox set up for a year with no issues before switching over to tuningwerks full carbon airbox
 

JimboFresh206

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Jan 29, 2018
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I recently installed the AEM closed intake on a customer's car and really thought it was nice.


I was also really liking all of the 740i intakes/inlets. has anyone else finished another set?

I have the air-box kicking around from before i decided on a single, and always ponder lol.
 

dcafs

New Member
Apr 27, 2019
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2008 135i
Z4 lid fits fine under stock cowl I ran the z4 lid and mr5 airbox set up for a year with no issues before switching over to tuningwerks full carbon airbox

Thank you for clarifying......I was considering purchasing it and you have made the decision clearer.

Did you find the Z4 lid reduced your WGDC over the stock lid?
 

BQTuning

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Jul 18, 2017
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E89 Z4 35i 6MT M Sport
Did you find the Z4 lid reduced your WGDC over the stock lid?

FWIW, here is a log I did on my E89 Z4 back in 2015 when it was stock. I did add about 1-2 gals of E85 though. The dyno shop was near 100°f in mid summer in south Florida. Car did limp on the dyno due to access heat, but wastegates remained rather low for the boost and hot ambient weather.


Please note: This should not be used to compare with upgraded twins which require more air and produce more air volume than stock turbos at the same PSI that more likely require more dutycyle under the same conditions and setup.