N55 BOV

[bogart]

N55 has a MAF in the air intake and a TMAP in the charge pipe. Since we do have a diverter valve built into the turbo housing, a BOV would be pointless, unless there was a way to disable the diverter valve.

I have the charge pipe from ER. It is definitely a good buy, but not meant for a BOV; it is meant for a stronger connection to the throttle body and the ability to upgrade to meth injection due to the threaded ports in the charge pipe.

I have the Injen CAI, new DME, and JB4 Stage 2. It is a good combination, but I have yet to switch back to the stock intake to see if there is a difference in torque. I get about 16 psi of boost. In map 2 with my DP and 93 octane, it is a great setup. The turbo and diverter valve can be heard very clearly with the Injen intake. Sometimes it is even a little too much, but I like it.

I plan on installing an FMIC, oil coolers, new HPF 3.5" exhaust, and meth this spring. Stay tuned.

[chopper817]

Originally Posted by 1SerieStud

Regardless of the system, it should recirculate back anywhere prior to the throttle body/intake manifold but past the maf sensor in order to recirculate, since the ecu will be compensating for this air already.

On the n55 i'm assuming it is being pushed back into the compressor housing, goes through the intercooler piping, intercooler, etc etc.

Conversions are feasible but require a bit of work on the electronic side.

But that doesn't make sense to me.....

It would have to vent it to a location prior to the turbo, other wise it would just be transferring let's say 15 psi into a part of the system that already has 15psi in it. So where is the path of transfer? And if it transfers the pressure to pre turbo then what would keep some of the pressure escaping out of the intake air filter? I want to understand the flow of pressure better.

[1SerieStud]

Originally Posted by chopper817

But that doesn't make sense to me.....

It would have to vent it to a location prior to the turbo, other wise it would just be transferring let's say 15 psi into a part of the system that already has 15psi in it. So where is the path of transfer? And if it transfers the pressure to pre turbo then what would keep some of the pressure escaping out of the intake air filter? I want to understand the flow of pressure better.

When the turbo compresses air, that compression (boost) is measured at the intake manifold and into the engine under acceleration. On a "normal" system, the bov/DV is mounted on the upper intercooler pipe which is what leads the air into the throttle body/intake manifold, and recirculates back into the intake pipe which is attached to the compressor housing of the turbo. So, if you look at the whole picture as a closed loop system, recirculating to the intake pipe, or to the compressor housing of the does not make a difference, because when recirculation is taking place, the car is not under boost anymore, and instead it's on vacuum mode. So the system is not pressurized and the air will not take the path of least resistance and out the intake system.

[ksahakian1]

Hey where did you get your 1M body kit?

[That_1_Guy]

Basic Answer..... there is no new BOV. If you want to hear it louder, get a BMS intake, take a chance at hurting performance, get a new Charge pipe, and be happy that you will be the only one hearing the louder noise.

I like the fact that the N55 doesn't have a loud BOV. Last thing I want to see with our cars is a bunch of Ricers get their hands on it, and throw some HKS RFL on it and go around revving their crap. Sames goes for people who want huge, blingy, shiny FMIC's.

Be proud your car is FI'd and doesn't need to show it off.

[boostaddict305]

since when is having a bigger fmic to cool the air better and a bov that can handle more pressure than the oem one before it starts leaking rice? recirc bovs arent too loud the ones that vent to atmoshere are the ones that you can hear from a half a mile away

[tboudre]

Originally Posted by Snertz

Can't see it in the pic but there is a vent right before the compressor in the housing, no extra piping needed. Essentially it's equivalent to venting into the intake, this is why you may hear the venting sound with aftermarket intakes as they don't muffle the sound as much as the stock tract.

Converting is possible, heard about it being done on other cars but it's a very involved process including changing out the ECM/ECU, or use a piggyback designed to do so.

edit : lol damn, 1SeriesStud beat me to the punch

Hey, I've been looking into upgrading my FMIC on my N55 335i and started to wonder about the BOV. Thanks for the info, and I can attest to the fact that I never heard my BOV until I installed my BMS Intake. Now I hear the turbo spooling & the BOV plain as day & I couldn't understand why. Now it all makes sense. Thanks. The BOV must vent back into the intake, and without the housing & the muffling factory air filter that is a closed system all the way to the front air scoops, it is audible since the installation of the BMS intake opens up the air box.

[jeffery_stearns]

Originally Posted by AnooooOH

which bovs are available for the n55 and where can I get them?

Forge offers a BOV for the M235i.

http://www.forgemotorsport.co.uk/Blo...uct--1306.html

[Ric in RVA]

Sorry to resurrect an old thread but there seems to be some wisdom here.

Do N55 turbos rattle? I have a faint metallic rattle (more like a knock) the seems to emanate from the passenger footwell at 1500 to 2000 rpm.

I noticed it first when I had my son drive the car.

Give it a little gas and it goes away. Put in clutch and coast it goes away.

Everything runs great, no codes.

Could be gear box rattle with no load too.

Maybe exhaust valves? ( i have tried full open and normal on JB4 and the sound seem the same. Doesn't mean the valve isn't rattling though)

Any ideas?

[bNks334]

Originally Posted by Ric in RVA

Sorry to resurrect an old thread but there seems to be some wisdom here.

Do N55 turbos rattle? I have a faint metallic rattle (more like a knock) the seems to emanate from the passenger footwell at 1500 to 2000 rpm.

I noticed it first when I had my son drive the car.

Give it a little gas and it goes away. Put in clutch and coast it goes away.

Everything runs great, no codes.

Could be gear box rattle with no load too.

Maybe exhaust valves? ( i have tried full open and normal on JB4 and the sound seem the same. Doesn't mean the valve isn't rattling though)

Any ideas?

How many miles?

Dual mass flywheel can start to rattle as it begins to fail.

[Ric in RVA]

Originally Posted by bNks334

How many miles?

Dual mass flywheel can start to rattle as it begins to fail.

55k

Third owner.

Interesting. Will have to see if I can rule that out as a source or confirm. Thanks!!

[Ric in RVA]

Originally Posted by Ric in RVA

55k

Third owner.

Interesting. Will have to see if I can rule that out as a source or confirm. Thanks!!

I swapped out the water thin BMW gearbox oil for Redline MTL. No more rattle!

[pito2121]

Ok was going to start a new thread but this was pretty much covering what I wanted to say. We've established the N55 has a compressor mounted diverter valve, which can be called a surge valve, pressure relief valve, etc. The reason for BMW using this set up is the valvetronic system on the N55.

The N54 is a conventional turbo set up. A set of twins blow into the boost tubes controlled by the wastegate, cooled through the intercooler, and into the engine with a set of DV valves (1 for each bank) controlling surges. In the N54 the throttle body is the primary means of air control going to the intake valves. When u close the throttle u get a vacuum in the manifold which can control the to diverter valves to release pressurized air. This is what I mean by conventional. The N54 runs of speed density (Map sensor) so flow isn't measure but calculated so if you stop diverting the air into the intake track it won't affect it. For this tuning the n54 is easier and makes it a better tuners engine. Why does BMW do this if they can vent it off? Remember BMW is appealing to the masses. Not everyone wants so sound like they're Tokyo drifting down the road while going to get groceries.

The N55 is BMWs evolution of the N54. Keep in mind the N54 was a rush to market engine and a first, for long time anyway, that bmw was mass producing a turbo engine. Despite the fact that the N54 was power crazy it wasn't efficient or a multi-purpose engine, so the N54 became useful for power only applications- ie the 1M, Z4, and 335is.

Now the N55 is completely different. The boost characteristics have to be controlled a lot more hence the reason for the single twin scroll conversion. The N55 has what's known as valvetronic. The valvetronic system gives the car the feel and control of individual throttle bodies by controlling the air intake at the valve themselves. The throttle body is used as a secondary or emergency means of air control unlike the N54. Because of this there is no clean pressure/vacuum signal coming off the manifold for which the DV/BOV can operate properly, because technically the manifold sees constant boost. How much boost depends on not only the wastegate but also the Electronic DV on the actual turbo housing. That's also why its electronic, so the DME can open it and close it depending on engine demands not just driver inputs. Also controlling the surge or pressure changes far from the intake ports makes for better air control on the valves because the throttle body is pegged open during all normal operation regardless of driver input on the N55. This difference in setup enables BMW to make the engine run smoother, cleaner, and more efficient without power losses, and gives it the ability to be used in a broad spectrum of cars because of the diversity of torque control with the combination of DI and valvetronic. In actuality the N55 was BMW's first engine ever to be used from the 1-series all the way up to the 7-series. For the this the N55 is a far superior engine design and a jackpot in the eyes of mass production for profit.

While the N54 is a great engine without a doubt its basis of existence is for power and sporty driving. Its conventional design make it something tuners are used to and comfortable with, enable a typical DV/BOV setup, and its required fortification gives it that strength enthusiast call "2JZ like". But in actuality the N55 is the better all around engine. The valvetronic system while not enabling the typical DV/BOV design and making it a bit more difficult to tune, gives it the edge on the N54 in ever other category but power production. But, I've noticed in the recent years as tuners got comfortable and gain more knowledge on the N55, the power production capabilities have been slowly realized.

I know its kind of lengthy but I figured a full explanation on the DV/BOV set up and BMWs thinking would be good to know.

[lopezpr]

Hello, I'm new to the group. I have a 2011 135i N55.

I bought it in 2013, and since then, I haven't had major issues with it.

It currently has 55,000 Miles, and it is bone stock besides a JB4 running on Map 1.

I noticed the spark plugs were never changed before, so I replaced them with the OEM Bosch spark plugs.

Now I'm running into an issue after replacing the sparkplugs. (it may not be related but it is when the problem started.) In addition to the spark plugs, the DMTL pump was triggering the check engine light, so I replaced that too with the OEM Bosch pump as well.

Going from there, I erased the code for the DMTL pump and it didn't come back, but the car wasn't feeling right. I could hear the turbo spool inside the vehicle like the goosh sound. The check engine light came on with a bunch of codes (I will post them at the end). So I took off the BMS charge pipe and thought of the O-ring, I replaced it and cleaned up the MAF Sensor because it had some oil residue (which I was told it is normal).

Even after replacing the O-ring the car still acting weird, around 1500 RPM, you can hear like the BOV opening too soon or who knows it is open all the time, and that's when I start hearing the turbo gooshing and not building boost.

I will upload a video, the codes and 2 Data loggings from JB4 on 3rd gear starting from 2000 rpm's to 6000 on full throttle.

I will appreciate any input that could help me to resolve this issue.

The current JB4 firmware is: N55_ISO_5_17_T5

DATALOG: https://mega.nz/folder/VVkXFBiK#az-HX616mii0b1A2QKBOlA

VIDEO:

CODES:
DME active codes -
2775 - Air mass, plausibility: Air mass too low.
28A0 - Intake pipe absolute pressure, plausibility: Pressure too high.
2BC0 - Mixture control: Fuel-air mixture too lean.
2C90 - Blow-off valve: Jammed closed.
3BD3 - Message (transmission data 4, 0x10A): Checksum incorrect, receiver DME, transmitter EGS/HIM.

- DME shadow (inactive) codes -
2820 - Absolute pressure sensor, intake pipe: Multiple fault.
2C42 - Mixture control: Multiple fault.

- Misc. information -
MHD build: version 1.8
Voltage 12.34V
Last flashed file : Unknown
VIN: WBAUC9C51BVM10023
CAS VIN: WBAUC9C51BVM10023
Factory software: 7615460
Current software: 7637870
ECU status: Normal operation

- Readiness -
Misfire: Complete.
Fuel System: Complete.
Components: Complete.
Catalyst: INCOMPLETE.
Heated Catalyst: Not avail.
Evaporative System: INCOMPLETE.
Secondary Air System: Not avail.
A/C Refrigerant: Not avail.
Oxygen Sensor: INCOMPLETE.
Oxygen Sensor Heater: INCOMPLETE.
EGR System: Complete.