N55 boost leak {datalog}

gachdavit

Private
Mar 25, 2022
42
7
0
Hello everybody,

I have a car 335i E90 {N55 PWG}.

A car has a boost leak (I am going to add `datazap` log (I logged this, from the 4th gear), and if someone has a time please review it. I am interesting in, how critical is this loss of power). In the log, sometimes difference between `boost bar` and `boost target bar` is a 10PSI and even more. Is this a crucial ? Firstable, I thought that `chargepipe` has a problem, but now it seems that `intake manifold` has a problems as well. On the car, there are aftermarket DP, CP, BOV, Intake, spark plugs, ignition coils, TIC pipe, etc (Stock turbo/Stock pumps). This moment, I am using {MHD stage2+} and {XHP stage3}.


---------------------------------------------------------------------


When I read about N55, people was talking, that N55 starts losing power ~ after 5500RPM, but my car doing this way earlier (This is visible in the log).

XHP tries to hit redline and when I do manual shifting I got the better results (Almost 1 seconds less, during 100-200 acceleration).

Currently, my strategy of shifting:
1 gear -> shift on 7000RPM
2 gear -> shift on 6900RPM
3 gear -> shift on (5500-5700RPM)
4 gear -> shift on (5500-5700RPM)
5 gear -> shift on (5500-5700RPM)

But in the 3/4/5 gears, a car has way better boost on 4900/5000RPM, maybe better to shift even earlier ? For example on 5000RPM instead of 5700 ?

How is your opinion ?

Thanks !

https://datazap.me/u/gachdavit/log-1645814386?log=0&data=4-5
 

wheela

Sergeant
Jun 4, 2021
407
235
0
Twin Cities, MN
Ride
2015 e84 X1 35i Msport
Your boost is low, and your wastegate duty cycle is extemely high. But your LTFT and STFT look good, and your load actual is low - that indicates you're not leaking any measured air that got sucked through the MAF, so don't think the problem is a boost leak. I'd check that you don't have any leaks in the vacuum system for your wastegate and boost solenoid - if you don't have enough vacuum available there your wastegate won't close properly and you'll stuggle to hit boost. If there are no leaks, I'd look into your boost solenoid next.

Edit: The same vacuum system also controls the exhaust flapper, so a leak in that part if the line can cause you boost problems as well.

Edit Edit: a bad diverter valve on your turbo compressor housing can also cause this. You mentioned you have a BOV, but n55 doesn't come with one. What kind if BOV is it? Vent to atmosphere or recirculating?
 
Last edited:
  • Like
Reactions: gachdavit

gachdavit

Private
Mar 25, 2022
42
7
0
Your boost is low, and your wastegate duty cycle is extemely high. But your LTFT and STFT look good, and your load actual is low - that indicates you're not leaking any measured air that got sucked through the MAF, so don't think the problem is a boost leak. I'd check that you don't have any leaks in the vacuum system for your wastegate and boost solenoid - if you don't have enough vacuum available there your wastegate won't close properly and you'll stuggle to hit boost. If there are no leaks, I'd look into your boost solenoid next.

Edit: The same vacuum system also controls the exhaust flapper, so a leak in that part if the line can cause you boost problems as well.

Edit Edit: a bad diverter valve on your turbo compressor housing can also cause this. You mentioned you have a BOV, but n55 doesn't come with one. What kind if BOV is it? Vent to atmosphere or recirculating?
Hello Sir,

I bought this https://x-ph.com/turbosmart-bov-kompact-em-dual-port-vr9-bmw-n55-e90-e92-f-series/. We change replaced an original BOV.
I bought this, because I liked it's sound and enjoy a lot with it. When I see statuses of `MHD`, it always shows me:

Blow off valve: clamp closed. (This is always shown on MHD). <<< Maybe this is an issue as well ?

Thanks !
 

RuskiRacer

Captain
Vendor
Jul 17, 2019
1,209
746
0
Ride
2009 e93 335i
The only people i know running a bov on there n55s are guys whove moved away from the stock turbo and are running a full frame turbo. I know a bov sounds awesome but for n55 stock and upgraded hybrid turbos the best solution is to put an aftermarket diverted valve on the turbo itself
 
  • Like
Reactions: gachdavit

gachdavit

Private
Mar 25, 2022
42
7
0
The only people i know running a bov on there n55s are guys whove moved away from the stock turbo and are running a full frame turbo. I know a bov sounds awesome but for n55 stock and upgraded hybrid turbos the best solution is to put an aftermarket diverted valve on the turbo itself
Gotcha !

It means, that install aftermakret BOV on N55 stock turbo is bad idea and maybe had a side effects ? {Maybe it will damage engine/turbo ?}
Also, diverter valve is valve which is installed inside chargepipe ? Is it correct ?

Thanks !
 

RuskiRacer

Captain
Vendor
Jul 17, 2019
1,209
746
0
Ride
2009 e93 335i
The diverted valve should be on the turbo compressor housing itself. Gfb and turbo smart make good aftermarket upgrades. I wouldn't say the bov is damaging anything there purpose is to prevent damage but i I think its messing with your tune.
 
  • Like
Reactions: gachdavit

gachdavit

Private
Mar 25, 2022
42
7
0
The diverted valve should be on the turbo compressor housing itself. Gfb and turbo smart make good aftermarket upgrades. I wouldn't say the bov is damaging anything there purpose is to prevent damage but i I think its messing with your tune.
I understand sir,

Thanks !
 

RuskiRacer

Captain
Vendor
Jul 17, 2019
1,209
746
0
Ride
2009 e93 335i

wheela

Sergeant
Jun 4, 2021
407
235
0
Twin Cities, MN
Ride
2015 e84 X1 35i Msport
The thing with the stock diverter valve (on the compressor housing) is it can fail in a way where the boost pressure leaks through the diverter valve back to before the compressor - so like a boost leak, only air isn't escaping the system so your trims don't get thrown off, and you generally can't detect it with a boost leak test (becasue both sides of the diverter valve are pressurized equally). So the only side affects are low boost and high duty cycle. Not saying you have a bad diverter valve as other things could cause your symptoms, but it's definately a possibility as they're known to fail.
 
  • Like
Reactions: gachdavit

gachdavit

Private
Mar 25, 2022
42
7
0
The thing with the stock diverter valve (on the compressor housing) is it can fail in a way where the boost pressure leaks through the diverter valve back to before the compressor - so like a boost leak, only air isn't escaping the system so your trims don't get thrown off, and you generally can't detect it with a boost leak test (becasue both sides of the diverter valve are pressurized equally). So the only side affects are low boost and high duty cycle. Not saying you have a bad diverter valve as other things could cause your symptoms, but it's definately a possibility as they're known to fail.
Thanks sir,

I am going to make a notes and visit a mechanic.

Everything above affects on performance as well ? Also, `power steering pump` has a big noise (When I rotate a steering wheel, it seems engine is on high load. Sometimes even tachometer value is changing). I think, this is big problem as well. Time to replace it.
 

RuskiRacer

Captain
Vendor
Jul 17, 2019
1,209
746
0
Ride
2009 e93 335i
Thanks sir,

I am going to make a notes and visit a mechanic.

Everything above affects on performance as well ? Also, `power steering pump` has a big noise (When I rotate a steering wheel, it seems engine is on high load. Sometimes even tachometer value is changing). I think, this is big problem as well. Time to replace it.
Should start by replacing that "lifetime" fluid and filter see if that helps anything. Shops will charge you thousands of dollars to replace the rack and pump
 

wheela

Sergeant
Jun 4, 2021
407
235
0
Twin Cities, MN
Ride
2015 e84 X1 35i Msport
That blow off valve: clamp closed error is usually from after market diverter valves with a spring installed. What happens is with the spring, it doesn't open as far when the DME commands it to open, so boost in the charge pipe diesn't drop as fast as the DME expects, so it throws this code (it's the DME saying it doesn't think your diverter valve is opening properly). As far as impact to your car, this usually can cause boost spikes, but shouldn't be damaging unless it's so bad your getting compressor surge. You're problem is low boost, so not sure if the code is related to your problem though.

Do you have any pics from when you installed this? It's installed on your compressor housing, right? Usually it's called a diverter valve, so when I saw blow off valve mentioned, I was thinking of a traditional blow off valve installed on your charge pipe.

If something got installed wrong with your bov, it could be leaking boost back to before your compressor causing your boost problem, but I don't see how that would create the "blow off valve: clamp closed" error, but who knows for sure🤷‍♂️

Here are some pictures regarding the vacuum system that controls the wastegate and the exhaust flapper (related to my previous comments) and a picture of my stock diverter valve on the compressor housing).
 

Attachments

  • Screenshot_20211111-092507_Drive.jpg
    Screenshot_20211111-092507_Drive.jpg
    131 KB · Views: 16
  • 20211202_140917.jpg
    20211202_140917.jpg
    268.3 KB · Views: 18
  • Screenshot_20211202-135243_Gallery.jpg
    Screenshot_20211202-135243_Gallery.jpg
    709.4 KB · Views: 20
  • 20211107_152832.jpg
    20211107_152832.jpg
    230.4 KB · Views: 20
  • Screenshot_20211202-131116_Gallery.jpg
    Screenshot_20211202-131116_Gallery.jpg
    89.8 KB · Views: 19
  • Like
Reactions: gachdavit

gachdavit

Private
Mar 25, 2022
42
7
0
That blow off valve: clamp closed error is usually from after market diverter valves with a spring installed. What happens is with the spring, it doesn't open as far when the DME commands it to open, so boost in the charge pipe diesn't drop as fast as the DME expects, so it throws this code (it's the DME saying it doesn't think your diverter valve is opening properly). As far as impact to your car, this usually can cause boost spikes, but shouldn't be damaging unless it's so bad your getting compressor surge. You're problem is low boost, so not sure if the code is related to your problem though.

Do you have any pics from when you installed this? It's installed on your compressor housing, right? Usually it's called a diverter valve, so when I saw blow off valve mentioned, I was thinking of a traditional blow off valve installed on your charge pipe.

If something got installed wrong with your bov, it could be leaking boost back to before your compressor causing your boost problem, but I don't see how that would create the "blow off valve: clamp closed" error, but who knows for sure🤷‍♂️

Here are some pictures regarding the vacuum system that controls the wastegate and the exhaust flapper (related to my previous comments) and a picture of my stock diverter valve on the compressor housing).
Thanks for your time,

My car's BOV was installed inside turbo area, you are right (Not in the chargepipe).

Also, I have a new message in `DME Error Code History`,

321C - Fuel tank ventilation system and purge air system, minor leak: Leakage greater than 1.0mm.

Are this error related to the previous one ?
Once I visit mechanic, I will make a photos how my current BOV installation looks like. Basically, will try to make a photos in home conditions as well.

Thans sir !