Dinan CAI filter options & my experience
 

So I've reviewed a bunch of threads on Xoutpost about replacing the Dinan's CAI filter and the list of air filters that can be used is kinda everywhere... so I'm putting together this list for convenience.
I have NOT tried any of these, but from quick measurements taken (I will be double checking soon) it seems these (and maybe more) model are available to use as options for the Dinan CAI system (I can not speak to any other CAI as clearance may be different than the Dinan air box/metal shroud)

measurements of Dinan d403-0410 air filter and of Dinan air box installed and clearances inside (see pics below).
D403-0410 measures:
Flange (rubber boot) ID: 101.6mm (4")
Base of filter medium: 138.4mm (5.45")
Top of filter medium: 112.3mm (4.42")
Length of filter medium: 163mm (6.42")
Length of air filter: 182mm (7.16")

EDIT: Volant/AFE/AEM links updated May 2021:
after 5 years of very successfully running the Volant Powercore, I'm tring the AEM DryFlow this time around. I feel the Volant is best for low maintenance, as you never need to wash it, but it is a great idea to remove and air compressor blow out the pleates from inside out. I did that yearly and yes some VERY FINE powder/dust came out slightly. BUT I want more grunt sound from the Air Intake kit (which is the ONLY reason I ever installed the Dinan CAI kit) and I know the Dinan/AEM/AFE cone air filters make the exhaust growl deeper from very temporarily using the old/used Dinan filter that came with the kit.

Another EDIT: So I received my 7" long AFE Brute Force and upon install, its a VERY TIGHT squeeze just to get it to sit in there. I'd definitely recommend a 6" long, at max air filter, so install/removal is much easier and you do not have to slightly misshappe the filter to get it on or off then. the issue comes from the metal tab that is welded to inner fender wall and normally supports the factory air box. Now my new AEM sits super tightly up to this beige tab. OOPS


Dinan: d403-0410 (needs to be oiled)
Replacement Air Filter for Dinan Cold Air Intake - Dinan, Leader in BMW Performance Parts and Upgrades


K&N: RU-2590 (needs to be oiled)
RU-2590 - K&N Universal Air Filters, Universal Rubber Filter direct from K&N


AFE: 21-91057 (does NOT need to be oiled) (7" long)
https://afepower.com/afe-power-21-40...y-s-air-filter
AFE also sells 2 other kinds which need to be oiled


AEM: 21-2057BF/DK models (does NOT need to be oiled)
https://www.aemintakes.com/21-2057bf...low-air-filter (brute force model, which just means its using a synthetic material instead of cotton/gauze) - just purchased this one to replace the 5 year old Volant (Donaldson) Powercore 61509
https://www.aemintakes.com/21-2057dk...low-air-filter (traditional media/material used)


Volant: Power Core 61509 (IS NOT oiled, but is NOT washable either) 99.9% air cleaned. Biggest rating out there.
http://www.volant.com
https://www.volant.com/products/powe...r-filter-61509 - I installed this BEAST of a filter (spring of 2016) and it DOES have to be installed at a slight angle to get it to fit inside the Dinan CAI metal shroud cover


I read on another Bimmer forum that the K&N is an exact replica in regards to sizing of the Dinan's d403-0410 filter. EDIT: they did use the same dimensions. See above.
I confirmed measurements. Since this is true, then the other filters I've listed are ALSO very close measurement options. with the AEM brand being the widest filter base and top, then the AFE brand then K&N/Dinan filters being narrowest (5.375" @ base, 4.375" at top). the AFE ones I've listed have more filter membrane as they have an inverted top instead of rubber sealed flat top, and therefore more air cleaning/intake.


just a comment on the Dinan CAI metal box/shroud VS the metal AFE stage 1 shroud...
the AFE takes advantage of the factory air cowl and allows air from this to be cowl directed towards the air filter (see red circle in pic). The Dinan air box does NOT allow airflow from the factory air cowl to enter the metal box. I'm sure you can find a way though to get the air into it somehow...but would require modification of the Dinan box.

Great info. I personally would stay away from the oiled media air filters. The pro S type filters work really well.Afe knows what they are doing.

I agree. I just figured I'd post them to make the list a bit more comprehensive for people who may want to run the oiled filters.

Good deal

Holy crap, this 6" column style airfilter by Donaldson (Volant partnered with them) is huge.

After driving with this Donaldson PowerCore air filter at multiple different speeds for a bit have to say that it mutes the sound of the CAI from a more beastly sound that it made with the Dinan/other brand cone style air filter but it is still slightly more beefy than just the factory air filter/air box.

So I have a question I'm hoping ppl can help with...
I have the Dinan CAI installed and it reallllly limits the amount of air that can enter the air filter since the factory air cowl is no longer useful (but does a great job at cooling down engine bay).

I've been thinking of putting slits OR a trunk air breather vent style system into the black plastic wheel well/internal fender near the air filter so it can breathe better yet water (*which is no problem for a Volant brand air filter) would not interfere with the filters operation.

anyone have thoughts?
Or suggestions?

air vents cut in wheel well plastic
 

So, instead of buying air vents and cutting BIG holes out of the inner fender to fit these flat air vents in a 3D plastic fender well I decided to cut my own air vent slots and bend the plastic back with the help of a heat gun. My work is reversible and I'd only need to add a dab of silicone as a sealant to weatherproof it back to factory.
lets see how it helps for air flow... I cant see it being a negative effect.

I would think adapting the factory air scoop to the Dinan system would be better because you get the benefit of forced air feeding at speed, and the air inlet is about as high as you can get, further from kicked up dust than in the wheel well.

I would have preferred to do something with the factory air cowl and plastic pipe to help feed air into CAI box but that would require cutting the metal box a fair bit and I'm not sure I wanna go that far since its so expensive. If I could get a hose built that could attach to factory air cowl and then attach to the existing circular hole on side of metal box then I would have but I don't know any places that can build that here. It would be the best solution by far to use the factory air cowl and hose to metal box for feeding cooler air!!

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I've considered options that might increase the airflow into the Dinan CAI for years. I've never done any modification. The reasons being that too often logic when dealing with airflow does not apply, much improvement with airflow in benefit needs to be combined with improvements to the rest of the air in/out and fuel in components and unless it is forced air such as with a turbo, supercharger or nitrous there is insignificant gain in torque at any RPM and very little HP improvement even at high speeds.

I know that Dinan spends a lot of time and money on R&D. My guess if connecting to the factory air inlet was beneficial they would have done so. One of the reasons Dinan may not have done so is that they found there is more air getting in from the full frontal approach than limiting it to the air inlet.

I have stayed with the Dinan oiled filter and clean it more often than necessary. The downside is that I have to be very careful in the re-oilng process as too much oil will cause the MAF to fail. The filter that came with the system did that--Dinan paid for the new MAF.

On the other hand, who knows, you may achieve noticeable gains and it certainly looks like you are having fun. If it works I think you might want to consider something to cover it except when you really need the additional air, especially when it rains or snows. If the filter gets soaked a Prius will leave you in the dust.

funny you mention the "cover" idea.
So when I was slotting the plastic fender well I was bending it down cause I was thinking it would help deflect rain and debris from entering the CAI box (or atleast minimize as much as possible). Its raing HARD our there today (I'm glad as its helping me R&D this procedure now) and I just checked and YES a few dropplets only have entered into the CAI box area now...so its got me thinking, about how to put a mesh or some othr filtering medium over the slots to stop the little bit of rain water that DID invade today...then I started thinking about snow that could blow into the open slots... so I may end up reversing the slots and bending the plastic slots closed and gluing shut like it never happened and just living with the existing airflow inside the box.
It just seems to me that there is very little ways for air to flow into the CAI box and I wonder if that could cause starvation for the Air/Fuel ratio mix and therefore reduce power?
these are just ideas and I can fully reverse my cutting/heating to bend plastic back thank god.
I may modify the intake pipe that attaches to the big air cowl and cut it at an angle so that when it touches the CAI box, there happens to be a small round hole in the side (not sure what its for honestly since I have a face-lifted e53) and this hole COULD allow some air in the box. No way is it adding a lot of air, but some extra outside air is better than none.
I MAY drop in a temp probe and see how the air temp fluctuates while driving/stationary/hot days/cold days...
BUT maybe Dinan got it correct.

EDIT: SO I did end up gluing on some mesh from a screen door. 2 layers that cross at 45° angles to increase filtering of particles that can come up through mesh layers.
Works great.

If you mean the small hole below the intake tube going to the engine it is for the line to the secondary air pump. Do you have the Dinan intake tube, MAF, throttle body and engine software?

Nope, just the CAI box and a Volant brand air filter installed (dry filter).
Do ypu have a pic of the small air line and where it goes? I am not sure where the secondary air pump is on the N62.

looked into the software but it would overwrite my existing custom software and those pesky Dinan e53 parts are hard to come by too.
I have debated even selling the Dinan CAI and re-installing the factory airbox. I feel like having the Dinan CAI without anything else is almost a waste...except for the soun I get. the Dinan air filter made the x5 sound like a BEAST. This Volant air filter makes it sound louder than factory air box, yet quieter than a cone style filter.

The reason I asked is that the gains in TQ/HP that Dinan posted for the CAI was 12TQ and 13HP but that was only when the engine software and Dinan throttle body is also nstalled. The software Dinan offered was optimized for the other components. Your software could be better though increased volume of the Dinan CAI is somewhat compromised by the smaller throttle body. I don't have a clue how much. What exhaust do you have? How much improvement in TQ/HP would you like to achieve?

I installed the factory 4.8iS exhaust after resonators.

I'd LIKE to achieve 1,000 WHP :p
BUT I did NOT do this CAI install to expect ANY gains what so ever.
I only did it for sound change to be honest. And I got that, so expectation met :)
If I could track down Dinan parts (throttle body and MAF) I'd buy them... but not a rush to pay a fortune for them.

I had a local seller offer me the full Dinan exhaust for $300 but I had my 4.8iS on and I like its grunt... in hind sight I should have bought it to get the quad tips back...

The enclosure will never cause a lean situation...it's a heat shield, and not air tight.

Another way you could maybe get more fresh air there without permanently modifying the box would be to remove the top cover, putting some weather strip on the sides and rear so that the hood seals the top of the box (ala AFE), and removing the hood weather strip above the passenger side headlight.

This looks to allow some air in between the gap of the hood and headlight, straight into your filter box.

But the stock air feed is still better IMO.

G3ood I like what you're saying BUT I worry the lack of weather stripping will allow too much "bypass" and potentially the bonnet would sit a bit funny (unless I just cut out a small section above headlamp...)
Hmmmmm. Things to ponder/attempt.

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Bypass as in salt/rocks/water/snow/dust.

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I dont think there will be too much bypass because incoming air will have to go up and over the radiator support before getting to the filter area IIRC.

Also, the hood will still sit pretty much the same way because the alignment is controlled by the hood stops by the fenders, not the weather strips.

Just some alternatives to explore. :)

While the Dinan CAI does reduce the temp to the engine it also increases the volume and velocity. Removing the cover likely reduce one or both. In either case the MAF adjusts The air/fuel mixture to the increased volume of air getting to the engine, preventing a lean condition.

What does the volant air filter look like and what is the part number? Can you provide a link?

Link of the actual Volant filter I purchased is in the first post of this thread.

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Okay thanks I see it now. Wow a $100 air filter that has great filtration capabilities (99.9%) but no mention of flow. You mentioned that the X5 sounds different with this air filter on vs the cone filter. Can you elaborate on the difference in sound with the Volant filter vs the traditional cone filter?Thanks

Just that it's quieter sound than the traditional cone filter (probably due to more filtering) yet it's beefier that the factory air box.

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ok, sorry to revive an old thread, but I just can't state enough how the N62, 4.4i, through a factory 4.8iS exhaust muffler system WITH this Dinan CAI box & Donaldson air filter sounds like a beefed up, and I mean BEEFED UP, X5. I honestly don't want to sell it and upgrade to a newer X5 as I worry it would never sound as mean as this. The in and outflow of air/exhaust is just something to be heard in person. SO MANY PEOPLE compliment the sound since I installed the Dinan CAI box/cone filter, then I removed the Dinan cone air filter and installed the Donaldson/Volant column filter and it still sounds simply eargasmic.
I may run the Dinan cone air filter a bit over summer to hear how it sounds again on a long highway haul. It is just unreal.

Just an update 4 years after I put my Donaldson/Volant air filter.
55k kms later,
This is how the filter looks and I put a clean, unoiled Dinan filter next to the Volant, for size comparison. I feel the Dinan would breathe more, now that I really compare the two.

The Volant seems to be slightly damp (around the black rubber base) yet feels dry to the touch.
Inside is spotlessly clean still. I have removed once a year and put a low-pressure air compressor hose to blow air from inside out. A weeee bit of dust comes out...
Anyhow, just an update.https://uploads.tapatalk-cdn.com/202...39c196fe7e.jpghttps://uploads.tapatalk-cdn.com/202...0f9f86f971.jpghttps://uploads.tapatalk-cdn.com/202...44ec5ef7a2.jpghttps://uploads.tapatalk-cdn.com/202...4572e9027d.jpghttps://uploads.tapatalk-cdn.com/202...bffd10c3da.jpg

:iagree:

time for a new AEM DryFlow air filter :)