Effect Of OEM Style And Aftermarket Performance Air Filters On Vehicle Parameters

[derekgates]

The AFe dry filter is better than OEM paper I believe, in flow and dust catching. Certainly that filter has more surface area. I don't get, though, why it was sucking in hot air? And how do you determine that, if I may ask?

Filippo

It isn't sealed; it will suck in hot air from engine bay. The 'snorkel' doesn't bring in air until a high rate of speed unless the box connected to it is sealed and is causing a pressure loss to force air in from the front of car (until pressure difference at a higher rate of speed). In the case of the AFe and BMS cones, the lower pressure areas are going to be the hotter areas of the engine bay. For a sealed intake (Momentum GT or stock box), air is coming in at all times from front of car before the radiator.

[EDIT] And yes, the dry filter is much better. The AFe setup uses the dry filters and I am also running the AFe dry filter 'drop in' for my stock airbox. Thanks to your thread for finding that fantastic information!

 

[fmorelli]

I'll have to see how mine seals up on the Z4. Will run a couple K type thermocouples when I install, and take some measurements.

Filippo

 

[derekgates]

I'll have to see how mine seals up on the Z4. Will run a couple K type thermocouples when I install, and take some measurements.

Filippo

Fantastic idea. That's what @BQTuning (BuraQ?) did https://www.e90post.com/forums/showpost.php?p=22096496&postcount=17 showing difference between BMS and stock box. Highlighted a 52*F drop in temps going into inlets.

 

[aus335iguy]

It isn't sealed; it will suck in hot air from engine bay. The 'snorkel' doesn't bring in air until a high rate of speed unless the box connected to it is sealed and is causing a pressure loss to force air in from the front of car (until pressure difference at a higher rate of speed). In the case of the AFe and BMS cones, the lower pressure areas are going to be the hotter areas of the engine bay. For a sealed intake (Momentum GT or stock box), air is coming in at all times from front of car before the radiator.

[EDIT] And yes, the dry filter is much better. The AFe setup uses the dry filters and I am also running the AFe dry filter 'drop in' for my stock airbox. Thanks to your thread for finding that fantastic information!

Sorry for the confusion - Yours isnt like mine. Mine was a stage 2 Afe which is a sealed box around a single (larger) cone filter. The only place it gets air from is the stock over the radiator inlet.

 

[derekgates]

Sorry for the confusion - Yours isnt like mine. Mine was a stage 2 Afe which is a sealed box around a single (larger) cone filter. The only place it gets air from is the stock over the radiator inlet.

Ah, no problem. I might have been confused. AFe has some confusing model numbers/names.


Turns out, BuraQ did some work on that AFe model as well (which his investigations/recommendations created the Momentum GT!): https://www.e90post.com/forums/showpost.php?p=11735900&postcount=1

He worked on sealing the lid much better than when it originally arrived: https://www.e90post.com/forums/showpost.php?p=11744875&postcount=14

And then dyno'd it compared to stock: https://www.e90post.com/forums/showpost.php?p=11800831&postcount=80 (it won)

 

[aus335iguy]

Yeah that’s why I bought it and I’m getting BQ to tune my car. His work in DCTs is without peer in my opinion.

 

[derekgates]

Yeah that’s why I bought it and I’m getting BQ to tune my car. His work in DCTs is without peer in my opinion.

Well, make sure you seal it up like the threads I linked. Otherwise it isn't an actual sealed intake... it is just an 'enclosure' (meaning it can suck in hot air from the engine bay just the same as a DCI setup would).

 

[fmorelli]

@BQTuning is about six steps ahead of this now, I think. I can't even keep track of what he's screwing around with now - some second gen variant of hoarding other BMW platform parts for his Z4 vacuum system and intake, which I assume include a BMW airbox. He'll eventually come up for air and defend himself .

Filippo

 

[derekgates]

@BQTuning is about six steps ahead of this now, I think. I can't even keep track of what he's screwing around with now - some second gen variant of hoarding other BMW platform parts for his Z4 vacuum system and intake, which I assume include a BMW airbox. He'll eventually come up for air and defend himself .

Filippo

Yes, this is all old news. He is working on a 7 series intake setup that has custom carbon fiber inlets to the turbos.

https://bmw.spoolstreet.com/threads/z4-sdrive35i-s-intake-upgrade-conversion.3033/

Last I read he was having issues clearing the strut brace with the 7 series airbox on the Z4:

https://e89.zpost.com/forums/showthread.php?t=1403666

Because the 740i engine cover raises upwards in order for the Y inlets to pass under it. The original cover lays flat horizontally on the engine top. The 740i intake box also raises upwards. The intake box is twice the size of the standard N54 intake box.

I am not going to go through all of that due to cost (it was over $1k?!). I just want as 'cool breathing' and quiet car as I can. It's my daily driver and a lack of fun roads means I don't go all out often.

[EDIT]: I say I won't go with this intake system, but I certainly will entertain it. I love the idea of having OEM look with far superior cool air being fed to turbos. Has some hurdles to overcome though!

[EDIT2]: I just noticed you are also in that zpost thread... hahaha, this is 'old news' to you!

 

[fmorelli]

He's got some new jam going now ...

Filippo

 

[Rcboosted2007]

Yes, this is all old news. He is working on a 7 series intake setup that has custom carbon fiber inlets to the turbos.

https://bmw.spoolstreet.com/threads/z4-sdrive35i-s-intake-upgrade-conversion.3033/

Last I read he was having issues clearing the strut brace with the 7 series airbox on the Z4:

https://e89.zpost.com/forums/showthread.php?t=1403666


I am not going to go through all of that due to cost (it was over $1k?!). I just want as 'cool breathing' and quiet car as I can. It's my daily driver and a lack of fun roads means I don't go all out often.

[EDIT]: I say I won't go with this intake system, but I certainly will entertain it. I love the idea of having OEM look with far superior cool air being fed to turbos. Has some hurdles to overcome though!

[EDIT2]: I just noticed you are also in that zpost thread... hahaha, this is 'old news' to you!

Add a methanol kit for temps. And go back to oem box. World will be better for you.

 

[derekgates]

Add a methanol kit for temps. And go back to oem box. World will be better for you.

Oh I am on stock box with a Z4 lid. Plenty happy with car but if another intake setup arrives that is sealed and allows for more air... sign me up!

Meth I am not keen on due to not wanting a piggy back control setup nor a tank. Just not something I want to worry about for my day to day. I admire plenty of meth setups though!

 

[matreyia]

Posting this just as a data point... The following was done many years ago on Spec racecar with a small NA motor, 200ish HP. Every HP counted for an advantage, though.

I did a fair amount of testing filters where I tested the OEM paper, K&N and a few others (can't remember all the brands) back to back on a dyno. No noticeable difference between any of them with power. So I ran the OEM paper one. Fast forward a couple of race events and back to the dyno and it was down on power. WTF??? I put new plugs, coils, checked cam timing and I don't even remember what anymore. I was pulling my hair out (whats left of it) and it turned out the paper filter had collapsed on itself. It was brand spankin new clean, but the accordion folds has sucked together and permanently deformed. Tossed another filter in there and instantly 7 more HP. Haven't run a paper filter in a racecar ever since. Now that I know to look for it I have seen other track friends have the same problem.

The paper filter just can't take the constant beating of 4k-7k rpms of airflow non stop over an extended amount of time such as a 50 minute sprint race or multiple hour long enduro.

Always had superb results with KN filters over stock in my experience. I can literally see an instant difference at the higher end of the rpm on highway...throttle response is my favorite thing about upgrading to those filters. They may not have as high a level of filtration but they do flow like hurricane.

I did a test one time with my cold air dinan intake unit... stock filter, then KN... there was no contest.

Now i have the afe cold air magnum unit with the 360 big cone filter....same thing. Super high flow and effortless throttle.

 

[Itsbrokeagain]

Still running a Dinan Lid with the snorkel (aka the rich Mr.5 intake) on my clients car with a stock bottom half of the airbox intact and factory location inlets. WGDCs have been perfectly fine and we just replaced both the cone filter and the stock location filter with fresh K&Ns (the old ones were grimy af). Not much intake woosh if anything, but you do hear the turbo whistling a lot more now.

 

[Optigrab]

I wonder how much of a difference changing from a single slat to a double slat kidney grill would make?

Seems like a significant amount (20-30%) of material would be removed from in front of the radiator and ducting

 

[fmorelli]

Hell just pull the slats. The Z4 with M-sport has tons of frontal air flow space. Correspondingly I was surprised how choked the 1M seems. Maybe I have that wrong ...

Filippo

 

[Optigrab]

Hell just pull the slats. The Z4 with M-sport has tons of frontal air flow space. Correspondingly I was surprised how choked the 1M seems. Maybe I have that wrong ...

Filippo

Seems pretty choked to me as well. I thought about doing the delete as i have horrible luck with things flying into my car i would surely end up with a damaged radiator. I need something there for protection lol