N55 BOV

[alpinewhite3series]

i know that the BOV is attached to the turbo, but what can i do to be able to hear the blow off valve open up while shifting so i can hear it in the cabin.?????

[BadM4]

roll down the windows lol

[alpinewhite3series]

well i heard it the other day for example i had the car on Sport mode with the DCT on sport and the DTC off n as i took a curb i floored it and i heard it go swwoosh i got goose bummps it was music to my ears.!!!

[achilles3000]

Originally Posted by alpinewhite3series

well i heard it the other day for example i had the car on Sport mode with the DCT on sport and the DTC off n as i took a curb i floored it and i heard it go swwoosh i got goose bummps it was music to my ears.!!!

Fart while you let of wot!!

[mike@fb]

It will sound nice when you lett off the throttle with the addition of an injen intake, but people have said the intake hurts performance with the new dme on the n55.

[AnooooOH]

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

[Alex_750whp]

Throw that shit away n54 FTW

[Sylon]

I believe the sound you are hearing is from the stock bypass valve. And if you want to hear it better, one way to increase the sound is by installing a cold air intake. You will also hear the turbo spool up a lot clearer too.

[1SerieStud]

Originally Posted by alpinewhite3series

i know that the BOV is attached to the turbo

Erroneous. The BOV/diverter is not attached to the turbo. This may not be relevant in terms of sounds but you may want to educate yourself as to how a turbocharged system works and where its components are.

[Harlequin]

Originally Posted by 1SerieStud

Erroneous. The BOV/diverter is not attached to the turbo. This may not be relevant in terms of sounds but you may want to educate yourself as to how a turbocharged system works and where its components are.

Perhaps you should "Educate" yourself on the N55 Engine...

For the new 2011+ N55 motors BMW relocated the diverter valve to the turbo housing but unfortunately failed to upgrade their flimsy plastic chargepipe to accommodate all that extra pressure. N55 chargepipe failures are common and the more boost you run the more likely you are to run in to the problem.

From here: http://www.n54tuning.com/index.php?_...d&productId=96

Up until now there hasn't been a way to add a BOV to the N55 Engine.

However, I just found this and it looks interesting...

http://www.**********s.com/Evolution...e-Pipe-N55.htm

[IMG]http://www.**********s.com/images/Products/EvolutionRacewerks/mini-n55chargepipe2a.jpg[/IMG]

The OEM diverter valve equipped on the N55 was never designed to hold high boost. Once the car is tuned the stock diverter pipe will begin to leak, losing your boost and your horsepower. Evolution Racewerks has addressed this problem with their new N55 diverter pipe.

Evolution Racewerks has finally released their N55 diverter pipe! **********s is proud to be one of the first to offer it to our customers. The Diverter Valve Upgrade Pipe is available in the same 2 finish. It is available in a mirror polish finish. It is also available in our Type III Hard Black Anodizing for the guys that want the stealthy, factory look. An added benefit of the Type III Hard Black Anodizing is that it hardens the aluminum piping and makes it more durable against accidental damage (like dropping the pipe).

On the factory diverter valve pipe features a sound baffle for the diverter valves. This sound baffle is connected on the side of the factory diverter valve pipe which splits airflow. This causes turbulence inside the pipe which slows the charge intake air velocity (speed of the air traveling inside the pipe). By removing this turbulence (by eliminating the factory diverter valve sound baffle), increased throttle response, decrease turbo lag and ultimately higher maximum power potential can be realized. Our Diverter Valve Pipe Upgrade eliminates this sound baffle and thus eliminating the unnecessary turbulence in the diverter valve pipe, keeping charge intake air velocity at it's maximum. 3" 6061 Aluminum piping was used to properly match the size of the throttle body as well.

[1SerieStud]

Originally Posted by Harlequin

Perhaps you should "Educate" yourself on the N55 Engine...



From here: http://www.n54tuning.com/index.php?_...d&productId=96

Up until now there hasn't been a way to add a BOV to the N55 Engine.

However, I just found this and it looks interesting...

http://www.**********s.com/Evolution...e-Pipe-N55.htm

[IMG]http://www.**********s.com/images/Products/EvolutionRacewerks/mini-n55chargepipe2a.jpg[/IMG]

really? Please show me ANY car with an OEM (plastic) BOV/diverter valved mounted to the turbo. It will probably last a full 5-10 minutes under WOT/full boost before it turns to lava. I don't want to make an argument out of this, but if you notice the part that they are referring to, as well as the replacement part, they are both pipes. There is no way, I repeat, NO WAY that a BOV can be mounted to a turbo and that it would withstand the high temperatures in order to function normally.

I don't know who you quoted up there since there is certainly no reference to the original poster, but that is rather inaccurate.

Now to further the education here, the main reason for which an N55 has not been able to use a BOV is the presence of a MAF (mass airflow sensor) - which the N54 motor does not have. This forces the N55 to recirculate whereas a BOV on the n54 motor can be vented to the atmosphere without any side effects such as running rich in between shifts.

I'm very familiar with the N55 motor - drove a '11 135i for a year and a half before switching to my 1M.

[Harlequin]

I also do not want to start an argument. I am not an expert by any means... I'm an computer engineer - not a mechanical one. And this is my first Turbo car.

Learning as I go...

I'm more than happy to be corrected but everything I've read about the N55 says that the DV is in the Turbo Housing. I don't know enough about it to know whether your statement that this is not possible is correct or not.

All I do know is that your initial post got my back up. It certainly seemed like you wanted to start a fight by your tone.

I've attached a cross-section of the twin scroll turbo on the N55. My understanding is that this diagram shows the DV at point 4.

Please feel free to explain why I and everything I've read so far are wrong and you are right.

(I'm serious about this. I want to learn and if you know something about it then I'm listening.)

PS: The quotes and pictures in my previous post are both from the links I included and I'm aware that the picture is a charge pipe and not a DV. I'm also aware that the N54 has the DV (or replacement.upgrade BOV) on the charge pipe.

[1SerieStud]

Originally Posted by Harlequin

I also do not want to start an argument. I am not an expert by any means... I'm an computer engineer - not a mechanical one. And this is my first Turbo car.

Learning as I go...

I'm more than happy to be corrected but everything I've read about the N55 says that the DV is in the Turbo Housing. I don't know enough about it to know whether your statement that this is not possible is correct or not.

All I do know is that your initial post got my back up. It certainly seemed like you wanted to start a fight by your tone.

I've attached a cross-section of the twin scroll turbo on the N55. My understanding is that this diagram shows the DV at point 4.

Please feel free to explain why I and everything I've read so far are wrong and you are right.

(I'm serious about this. I want to learn and if you know something about it then I'm listening.)

PS: The quotes and pictures in my previous post are both from the links I included and I'm aware that the picture is a charge pipe and not a DV. I'm also aware that the N54 has the DV (or replacement.upgrade BOV) on the charge pipe.

Actually glad to hear you're a computer engineer, so am I I now understand your curiosity and desire to learn about the subject given the way we are wired!

My initial reply was not intended to start any arguments, it's just difficult to portray tone via typing. But just so you have an idea, exhaust gas temperatures (egt's) of 1000F and over are not rare, and this has to pass through the turbine housing of the turbo which is what keeps the turbine spinning. Mounting a plastic diverter valve anywhere near would be a recipe for disaster. Even aftermarket metal ones would most likely fail rather quickly.

I am currently using the app on my iPhone to respond, but when I get home I will look at the cross-sectional image you're referring to. Without looking at it, there's a possibility you may be referring to the waste gate of the turbo.

From computer engineer to computer engineer, cheers!

[Snertz]

Harlequin is right in this case, on the N55 the diverter valve is built into the compressor housing on the N55. If the heat from the turbine side were that big of an issue your intake tract feeding the turbo, and charge pipe going from would have melted long ago as well as that is all plastic too.


Item 14 & 16

Item 5 - Diverter valve

This is not uncommon, for instance it is the same setup used on Borg Warners EFR line :

http://www.motoiq.com/magazine_artic...ature-set.aspx
http://www.turbodriven.com/en/perfor...urbos/efr.aspx

Originally Posted by 1SerieStud

But just so you have an idea, exhaust gas temperatures (egt's) of 1000F and over are not rare, and this has to pass through the turbine housing of the turbo which is what keeps the turbine spinning. Mounting a plastic diverter valve anywhere near would be a recipe for disaster. Even aftermarket metal ones would most likely fail rather quickly.

The temps you're quoting are applicable on the turbine side of the turbo, the temps seen on the compressor side are much lower in comparison.

[Snertz]

http://www.e90post.com/forums/showth...&highlight=N55

After a little searching, I guess it shouldn't be surprising that it's setup this way, it appears that BorgWarner is the supplier to BMW for the N55 turbo setup. Just look for their logo in the casting

I wonder if it would be possible to relocate the MAF to a post turbo location, perhaps in the upper charge pipe immediately before the throttle body (like where the MAP sensor is on the N54) This could allow a vent to atmosphere BOV before it, but not sure if the MAF would tolerate boost, and would likely need to be calibrated for the new location.

[1SerieStud]

Very interesting fellas...I stand corrected. I have what I consider to be an extensive background in turbocharged applications, have built my own setups in the past, but I have never seen a setup like this before.

Good information nonetheless!

[Snertz]

Yah same here, not sure if there was any reason this was done other than from a cost perspective. Never seen it with any other turbo manufacturers either OEM or aftermarket.

Intrestingly enough though, BW does offer a block off plate for the EFR's to allow usage of an external recirq or BOV.

[chopper817]

Ok, I have to ask this question.....

Where does the diverted valve divert the pressurized air to when it actuates?

I don't see any place or piping that would move the already accounted for air bact into the intake....

Or am I confused about how this system works. Someone please explain this to me.

And can you convert your MAF to a MAP?

[1SerieStud]

Originally Posted by chopper817

Ok, I have to ask this question.....

Where does the diverted valve divert the pressurized air to when it actuates?

I don't see any place or piping that would move the already accounted for air bact into the intake....

Or am I confused about how this system works. Someone please explain this to me.

And can you convert your MAF to a MAP?

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.

[Snertz]

Originally Posted by chopper817

Ok, I have to ask this question.....

Where does the diverted valve divert the pressurized air to when it actuates?

I don't see any place or piping that would move the already accounted for air bact into the intake....

Or am I confused about how this system works. Someone please explain this to me.

And can you convert your MAF to a MAP?

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

[Sylon]

I learned a lot in this thread just now about our turbo setup. Good information in here, nice work.


Also, bypass valve, diverter valve, same damn thing, lol. Where are you guys getting all these diagram pics at? I would like to learn a bit more.

[Harlequin]

Originally Posted by Sylon

Where are you guys getting all these diagram pics at? I would like to learn a bit more.

I get them off the interweb... through a Series of tubes...