[junlikesf30s]

Sup all! New here! First post!

Back story:
Picked up my 2016 F36 435i with 65k miles a month ago from BMW Mountain View and it's been amazing. All stock power wise; no intake, no exhaust, no tune.


Need some insight/advice/help:
- No codes with paper filter for my first 200 miles. Did a poor man's MPPK air box mod for more woosh; cut an opening next to the OEM air ram funnel and routed a dryer hose down behind the driver's side headlight, also removed the plastic plate behind the fog light grill to feed in fresh air into that section. Drove another 200 miles. I wanted MORE WOOSH, so I bought a K&N drop in filter and installed it, noticed a bit of stumbling at idle, but I was fine with it, drove about 30 miles on the highway then I popped a P00BD code.

- I clear it, assuming DME needs to adjust for high flow air filter. It pops back up within 5mins of highway driving on my way back home.

- I spray the MAF down with MAF cleaner and let the filter sit on a paper towel over night to soak up excess oil, the next day I disconnect the battery for 15min to let adaptations reset, slap everything together, start the car and let it idle for 15min, and boom, 15 miles on the highway I pop P0171 and P00BD.

- I'm thinking maybe I just have to clear it and drive, maybe the DME is still adjusting, so I get off the highway and pull into a parking lot, clear the code, and hop back on the highway, and within 5min on the highway, CEL comes back for P0171.

- I'm confused and panicking, thinking maybe something broke/cracked/etc by coincidence or when I changed the air filter; I'm thinking vacuum leak, fouled spark plugs, dying fuel pump. I pull into a gas station, clear the codes, and pop in the paper filter; the weird stumbling at idle is gone. I drive randomly on the highway for 40 miles, no codes.

- The next day I decide to give the K&N another try and swap it in. AGAIN, P0171+P00BD at around the 14-15 mile mark on the highway. I pull into a gas station, clear the codes, swap in the paper filter again.

- I've been driving with the paper filter for the last 150 miles now and no codes. Less woosh, but less headache/fear lol.


My questions for you fine and experienced BMW/N55 owners:
- Is this normal? Are the MAF parameters that strict that I can't install a "high flow air filter" without triggering a code and forcing fuel injectors to adjust?
- Is something else causing the codes with the K&N drop in?
- This may be a stupid question, but if it's an air flow issue with the K&N that's causing P00BD+P0171, would an axle back cause codes too since the engine would be able to exhaust gasses with less restriction?


Any insight, suggestions, feedback, etc are all greatly appreciated.

[Jvac]

Originally Posted by junlikesf30s

Sup all! New here! First post!

Back story:
Picked up my 2016 F36 435i with 65k miles a month ago from BMW Mountain View and it's been amazing. All stock power wise; no intake, no exhaust, no tune.


Need some insight/advice/help:
- No codes with paper filter for my first 200 miles. Did a poor man's MPPK air box mod for more woosh; cut an opening next to the OEM air ram funnel and routed a dryer hose down behind the driver's side headlight, also removed the plastic plate behind the fog light grill to feed in fresh air into that section. Drove another 200 miles. I wanted MORE WOOSH, so I bought a K&N drop in filter and installed it, noticed a bit of stumbling at idle, but I was fine with it, drove about 30 miles on the highway then I popped a P00BD code.

- I clear it, assuming DME needs to adjust for high flow air filter. It pops back up within 5mins of highway driving on my way back home.

- I spray the MAF down with MAF cleaner and let the filter sit on a paper towel over night to soak up excess oil, the next day I disconnect the battery for 15min to let adaptations reset, slap everything together, start the car and let it idle for 15min, and boom, 15 miles on the highway I pop P0171 and P00BD.

- I'm thinking maybe I just have to clear it and drive, maybe the DME is still adjusting, so I get off the highway and pull into a parking lot, clear the code, and hop back on the highway, and within 5min on the highway, CEL comes back for P0171.

- I'm confused and panicking, thinking maybe something broke/cracked/etc by coincidence or when I changed the air filter; [...]

I had the same problem when I combined the Mppk lower airbox with the k&n filter. Posted about it here but nobody else could relate. Mppk airbox with oem filter, no issue. K&n with stock airbox, no issue. Both together would cause the code every time moderate throttle or more. Tried cleaning maf, didn't help. I sold the Mppk airbox and kept the k&n filter and everything has been fine over 11000 miles since then. Never saw the code again. It's as if the 2 together just push more air than the system knows what to do with.

[junlikesf30s]

Originally Posted by Jvac

I had the same problem when I combined the Mppk lower airbox with the k&n filter. Posted about it here but nobody else could relate. Mppk airbox with oem filter, no issue. K&n with stock airbox, no issue. Both together would cause the code every time moderate throttle or more. Tried cleaning maf, didn't help. I sold the Mppk airbox and kept the k&n filter and everything has been fine over 11000 miles since then. Never saw the code again. It's as if the 2 together just push more air than the system knows what to do with.

What!?

What a weird issue. I assumed the MPPK or a modded lower airbox def would not be an issue, it's just an extra hole next to the funnel that's already there lol, AND ITS BEFORE THE MAF. You've personally confirmed it, so I guess I need to decide if I want to keep the K&N and revert my airbox mod OR keep the airbox mod and run paper.

So, the MPPK/modded airbox+paper will run cleaner and allow more fresh/cool air to the filter, but the stock airbox+K&N sounds better and allows more air to what matters, which is the turbo.

Hmmmm what to do...

Thanks for your reply!

[F32Fleet]

Junk the K&N. It's 1950's era filtering technology.

[Jvac]

Originally Posted by F32Fleet

Junk the K&N. It's 1950's era filtering technology.

Sounds familiar. I stuck with it though because I could get a better resale price for the Mppk airbox. K&n works fine, just not together with the airbox mod

[junlikesf30s]

I ordered the CTS intake last night after hearing a friend of a friend's F30 335i lol.

Sounds amazing in person, apparently a lot of people dont pop codes with a stock tune, something to do with how they designed the portion of the tube for the MAF. I'll just have to deal with swapping the stock tube+box in for smog.

I think what's happening with the MPPK+K&N is that there's way too much air flow for the MAF to handle at it's stock location+stock DME settings. Has to do with the stock closed box panel filter design with ram air forcing too much air through the filter, which is why I was only popping codes on the highway, would also explain why the paper filter isn't popping codes since it's thick/dense. If I dropped the $1800 for the MPPK from BMW, they would install the MPPK airbox and remove fogs for more ram air, then they would tune the DME, which I assume is changing MAF parameters along with upping boost, but I'd never do that for 20-30hp, I'd rather BM3/MHD it. Not a part of my plans for the car for a while though, going to wait for my extended warranty to expire first in 40k miles/5 years.

Moving to a cone design like the CTS, along with their MAF housing, i wouldn't be ramming air passed the filter, instead just filling the area around the filter with cool outside air for the intake to suck in. Which is why people with a stock tune don't complain about the CTS or Injen intakes popping MAF codes, but the Dinan does because it's a closed box, and I bet those complaining about the Dinan are running the MPPK lower airbox too lol.

TLDR;
closed box design + air ram + higher flowing filter = codes
open intake design + air ram = ok

[Billfitz]

Originally Posted by F32Fleet

Junk the K&N. It's 1950's era filtering technology.

For sure. Super high flow filters had value when cars had carburetors. Turbo charged engines don't benefit from them, and in some cases they make things worse.

[thejeremyman9]

Originally Posted by junlikesf30s

I ordered the CTS intake last night after hearing a friend of a friend's F30 335i lol.

Sounds amazing in person, apparently a lot of people dont pop codes with a stock tune, something to do with how they designed the portion of the tube for the MAF. I'll just have to deal with swapping the stock tube+box in for smog.

I think what's happening with the MPPK+K&N is that there's way too much air flow for the MAF to handle at it's stock location+stock DME settings. Has to do with the stock closed box panel filter design with ram air forcing too much air through the filter, which is why I was only popping codes on the highway, would also explain why the paper filter isn't popping codes since it's thick/dense. If I dropped the $1800 for the MPPK from BMW, they would install the MPPK airbox and remove fogs for more ram air, then they would tune the DME, which I assume is changing MAF parameters along with upping boost, but I'd never do that for 20-30hp, I'd rather BM3/MHD it. Not a part of my plans for the car for a while though, going to wait for my extended warranty to expire first in 40k miles/5 years.

Moving to a cone design like the CTS, along with their MAF housing, i wouldn't be ramming air passed the filter, instead just filling the area around the filter with cool outside air for the intake to suck in. Which is why people with a stock tune don't complain about the CTS or Injen intakes popping MAF codes, but the Dinan does because it's a closed box, and I bet those complaining about the Dinan are running the MPPK lower airbox too lol.

TLDR;
closed box design + air ram + higher flowing filter = codes
open intake design + air ram = ok

You aren't "ramming air" unless you have the AFE scoop, and even then, you'd have to be going fast at low throttle for you to be forcing more air in than the engine is even demanding. It's highly unlikely its a mass airflow issue, more likely the way the flow is being disturbed with the K&N. It basically has to be a filter issue, since myself and plenty of other people run MPPK airbox mod + AFE pro dry-s drop in filter without issue.

CTS is a good intake due to the MAF design as you mentioned. The issue with the Dinan is the MAF design.

https://f30.bimmerpost.com/forums/sh....php?t=1765289

[terryd5150]

Originally Posted by thejeremyman9

You aren't "ramming air" unless you have the AFE scoop, and even then, you'd have to be going fast at low throttle for you to be forcing more air in than the engine is even demanding. It's highly unlikely its a mass airflow issue, more likely the way the flow is being disturbed with the K&N. It basically has to be a filter issue, since myself and plenty of other people run MPPK airbox mod + AFE pro dry-s drop in filter without issue.

CTS is a good intake due to the MAF design as you mentioned. The issue with the Dinan is the MAF design.

https://f30.bimmerpost.com/forums/sh....php?t=1765289

Bookmarked.

[junlikesf30s]

Originally Posted by thejeremyman9

You aren't "ramming air" unless you have the AFE scoop, and even then, you'd have to be going fast at low throttle for you to be forcing more air in than the engine is even demanding. It's highly unlikely its a mass airflow issue, more likely the way the flow is being disturbed with the K&N. It basically has to be a filter issue, since myself and plenty of other people run MPPK airbox mod + AFE pro dry-s drop in filter without issue.

CTS is a good intake due to the MAF design as you mentioned. The issue with the Dinan is the MAF design.

https://f30.bimmerpost.com/forums/sh....php?t=1765289

Hmm, interesting. I was considering ordering the AFE drop in, but figured $70 for K&N already, then another $80 for AFE, I may as well return the K&N and order the CTS intake lol.

So why is it that another user confirmed that K&N+MPPK caused codes, but K&N+stock lower airbox was fine? Is that just another factor in disturbance of air flow, as in the MPPK/mod is just enough of an extra opening to make the K&N pop codes? Just blows my mind how sophisticated the DME is.

Also, yes! If I was just driving around town, running errands, 30-40mph, etc, the codes never popped. I was definitely ONLY popping the P00BD and/or the P0171 during highway speeds/RPMs; 70-75mph @ 1600-1800rpm in comfort or 2200-2500rpm in sport/sport+. I don't know if this plays a factor in the ram air, because as you said, I don't have the AFE scoop, I do however have a tube from the MPPK mod hole that routes behind/down the driver's side headlight and into the area behind the driver's side foglight/grill area.

Are you tuned btw? I read that tunes would ultimately fix the MAF codes so the injectors don't go crazy.

Thanks for the link, gonna bookmark it.

[thejeremyman9]

Originally Posted by junlikesf30s

Hmm, interesting. I was considering ordering the AFE drop in, but figured $70 for K&N already, then another $80 for AFE, I may as well return the K&N and order the CTS intake lol.

So why is it that another user confirmed that K&N+MPPK caused codes, but K&N+stock lower airbox was fine? Is that just another factor in disturbance of air flow, as in the MPPK/mod is just enough of an extra opening to make the K&N pop codes? Just blows my mind how sophisticated the DME is.

Also, yes! If I was just driving around town, running errands, 30-40mph, etc, the codes never popped. I was definitely ONLY popping the P00BD and/or the P0171 during highway speeds/RPMs; 70-75mph @ 1600-1800rpm in comfort or 2200-2500rpm in sport/sport+. I don't know if this plays a factor in the ram air, because as you said, I don't have the AFE scoop, I do however have a tube from the MPPK mod hole that routes behind/down the driver's side headlight and into the area behind the driver's side foglight/grill area.

Are you tuned btw? I read that tunes would ultimately fix the MAF codes so the injectors don't go crazy.

Thanks for the link, gonna bookmark it.

I dont disagree there is a KN+MPPK issue. Your post isnt the first time i heard it. But the fact that there is MPPK+stock or MPPK+AFE filter basically says the issue is with the KN filter with that specific airbox configuration. Given that other people did not have your air tube, that should also not be the cause. For some reason it seems the K&N is creating turbulence or in some way affecting the flow at the MAF when the MPPK hole is added.

Yes i am tuned. Also i am pretty sure the other people who reported the K&N issue were also tuned. The tune shouldnt have any impact on these MAF codes coming up or not, but someone with KN could test that if they wanted to.

[junlikesf30s]

Originally Posted by thejeremyman9

I dont disagree there is a KN+MPPK issue. Your post isnt the first time i heard it. But the fact that there is MPPK+stock or MPPK+AFE filter basically says the issue is with the KN filter with that specific airbox configuration. Given that other people did not have your air tube, that should also not be the cause. For some reason it seems the K&N is creating turbulence or in some way affecting the flow at the MAF when the MPPK hole is added.

Yes i am tuned. Also i am pretty sure the other people who reported the K&N issue were also tuned. The tune shouldnt have any impact on these MAF codes coming up or not, but someone with KN could test that if they wanted to.

ty for your input. i appreciate your insight

[Jvac]

I also run a dinan stage 2 tune with my k&n. I don't think I bothered to disable it at the time I was trying out the Mppk airbox so I can't be sure if having the tune is or isn't a factor, other than to say that the code came up when the tune was enabled.

[junlikesf30s]

Originally Posted by Jvac

I also run a dinan stage 2 tune with my k&n. I don't think I bothered to disable it at the time I was trying out the Mppk airbox so I can't be sure if having the tune is or isn't a factor, other than to say that the code came up when the tune was enabled.

Interesting. So it looks like the N55s just don't like the K&N with MPPK/extra air flow. Good to know.

[arekuf3x]

The weakest link of the intake is turbo inlet, mppk intake is good even with bigger turbo. But that’s interesting that aftermarket filter doesn’t work well with mppk intake, I always kept stock filter. Even with pure500 turbo, mpe exhaust is must imo for a n55.

[terryd5150]

Originally Posted by thejeremyman9

I dont disagree there is a KN+MPPK issue. Your post isnt the first time i heard it. But the fact that there is MPPK+stock or MPPK+AFE filter basically says the issue is with the KN filter with that specific airbox configuration. Given that other people did not have your air tube, that should also not be the cause. For some reason it seems the K&N is creating turbulence or in some way affecting the flow at the MAF when the MPPK hole is added.

Yes i am tuned. Also i am pretty sure the other people who reported the K&N issue were also tuned. The tune shouldnt have any impact on these MAF codes coming up or not, but someone with KN could test that if they wanted to.

There may not be an immediate answer in this moment, but with your testing on intakes and inlets you might have some perspective here:

MPPK + AFE Pro Dry + MST V2 inlet - would this work with a Pure 500 without throwing codes while still keeping WGDC low, as opposed to a CTS intake?

Tune would be OTS MHD stage 2 or the new 2+ (whenever the HPFP arrives).

I prefer the underhood look of the OEM package, but I don't drive around with the hood open - I'd rather have the max performance benefit.

My Spidey sense tells me the CTS has the capability to flow more air, but that's only anecdotal observation - I've never done a physical measurement/side-by-side comparison.

[AmuroRay]

Originally Posted by thejeremyman9

I dont disagree there is a KN+MPPK issue. Your post isnt the first time i heard it. But the fact that there is MPPK+stock or MPPK+AFE filter basically says the issue is with the KN filter with that specific airbox configuration. Given that other people did not have your air tube, that should also not be the cause. For some reason it seems the K&N is creating turbulence or in some way affecting the flow at the MAF when the MPPK hole is added.

Yes i am tuned. Also i am pretty sure the other people who reported the K&N issue were also tuned. The tune shouldnt have any impact on these MAF codes coming up or not, but someone with KN could test that if they wanted to.

I ran MPPK box and AFE (for sale if anyone wants it) with zero issues as well. I’m with you, this is a K&N filter issue and the way it distributes air towards the MAF.

You could use an air straightener or a velocity stack in the box - but you shouldn’t need that on a stock airbox.

[AmuroRay]

Originally Posted by terryd5150

There may not be an immediate answer in this moment, but with your testing on intakes and inlets you might have some perspective here:

MPPK + AFE Pro Dry + MST V2 inlet - would this work with a Pure 500 without throwing codes while still keeping WGDC low, as opposed to a CTS intake?

Tune would be OTS MHD stage 2 or the new 2+ (whenever the HPFP arrives).

I prefer the underhood look of the OEM package, but I don't drive around with the hood open - I'd rather have the max performance benefit.

My Spidey sense tells me the CTS has the capability to flow more air, but that's only anecdotal observation - I've never done a physical measurement/side-by-side comparison.

There is a slight power gain, but nothing more than a handful of HP. I would invest in an inlet first, and stick with the MPPK + drop in unless you want the extra sound.

[thejeremyman9]

Originally Posted by terryd5150

There may not be an immediate answer in this moment, but with your testing on intakes and inlets you might have some perspective here:

MPPK + AFE Pro Dry + MST V2 inlet - would this work with a Pure 500 without throwing codes while still keeping WGDC low, as opposed to a CTS intake?

Tune would be OTS MHD stage 2 or the new 2+ (whenever the HPFP arrives).

I prefer the underhood look of the OEM package, but I don't drive around with the hood open - I'd rather have the max performance benefit.

My Spidey sense tells me the CTS has the capability to flow more air, but that's only anecdotal observation - I've never done a physical measurement/side-by-side comparison.

IMO the only factor that should inform your decision to run CTS vs. the MPPK setup you mentioned is sound, the difference in performance will not be tangible. The CTS might have the potential to get a few more peak HP, but i personally would not deal with the sound of the CTS to gain said HP. Also there are lots of people running MPPK with bigger turbo/power setups, even on stock filter.

[junlikesf30s]

Little update:
Received and installed the CTS intake. For $265 shipped to my door, it's a good purchase.

I agree with you thejeremyman9 , the sound is a little obnoxious at times. For the stock 7-10psi tune, the turbo howls and the diverter valve hisses pretty hard. The car sounds like a Japanese tuner car now lol.

I'll run it for now, but I'm considering going back to the modded stock box/mppk with the AFE drop in. Maybe the Valvetronic axle back would balance sounds coming from the front and rear of the car?

Put 100 miles on the car since I installed the CTS intake, and so far so good, no CEL.

[thejeremyman9]

Originally Posted by junlikesf30s

Little update:
Received and installed the CTS intake. For $265 shipped to my door, it's a good purchase.

I agree with you thejeremyman9 , the sound is a little obnoxious at times. For the stock 7-10psi tune, the turbo howls and the diverter valve hisses pretty hard. The car sounds like a Japanese tuner car now lol.

I'll run it for now, but I'm considering going back to the modded stock box/mppk with the AFE drop in. Maybe the Valvetronic axle back would balance sounds coming from the front and rear of the car?

Put 100 miles on the car since I installed the CTS intake, and so far so good, no CEL.

Yup... Now double the boost and the air suction noise under throttle is overwhelming. The main annoyance i had (if you like those suction sounds) was at part throttle or on/off throttle when the DV hisses and squeals. I main gripe (person preference) is that the air sound isnt even a good turbo sound IMO. I have a 91 3000gt TT with an open air filter intake and it sounds much more like a turbo spooling than a bunch of air rushing, if that makes sense.

[terryd5150]

Originally Posted by thejeremyman9

Yup... Now double the boost and the air suction noise under throttle is overwhelming. The main annoyance i had (if you like those suction sounds) was at part throttle or on/off throttle when the DV hisses and squeals. I main gripe (person preference) is that the air sound isnt even a good turbo sound IMO. I have a 91 3000gt TT with an open air filter intake and it sounds much more like a turbo spooling than a bunch of air rushing, if that makes sense.

I love the sound of a turbo spooling up - I love ported compressor covers for this reason - but I'm not a huge fan of just the sound of air being sucked into a tube.