Stock N54 boost 6 psi ?

Hill'n'toe

Private
Mar 12, 2018
37
3
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335Xi
Hi guys,

Not here for a long time, this forum is an interesting database.

I post because I've done my first log yesterday and of course I've got questions..

Here's the log : https://datazap.me/u/hillntoe/n54-stock-4th?log=0&data=3-5-24

I've seen that usually the stock boost pressure peak is 8.5 psi and mine is approx 6...
I don't know if there is a difference between US and EU cars but, the thing is the boost is the bost target..

If anyone can help.

Thanks
 
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Clean WHP

Corporal
Apr 24, 2017
173
136
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2010 135i Msport 6MT
I cant see why higher ambient air or higher IAT's would mean more boost. If anything shouldn't it be less boost with higher temps and mor boost with lower temps? Is there something im missing?
 

veer90

Captain
Nov 16, 2016
1,000
762
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West Nyack, NY
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e90 335i 6MT
DME targets a specific load and the calculation is based on IAT among other things. The idea is to get the motor making about the same power at 100F and 32F ambient, probably for emissions purposes.

Either way it's stupid.
 
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titium

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Nov 8, 2016
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Australia
DME targets a specific load and the calculation is based on IAT among other things. The idea is to get the motor making about the same power at 100F and 32F ambient, probably for emissions purposes.

Either way it's stupid.

I disagree it's not stupid. It's to make the car have the same output and feel the same under almost all conditions. More about drivability then emissions.
 
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veer90

Captain
Nov 16, 2016
1,000
762
25
West Nyack, NY
Ride
e90 335i 6MT
I disagree it's not stupid. It's to make the car have the same output and feel the same under almost all conditions. More about drivability then emissions.

Maybe on stock boost the driveability is the same, but I can tell you on my 22 psi pump gas tune that was dialed in around 70* during the summer there is a big difference when it drops boost down to 14 psi in the winter.
 

titium

Private
Nov 8, 2016
48
9
0
Australia
Maybe on stock boost the driveability is the same, but I can tell you on my 22 psi pump gas tune that was dialed in around 70* during the summer there is a big difference when it drops boost down to 14 psi in the winter.

That's down to your specific tune not the concept itself....
 

doublespaces

General of the Army
Oct 18, 2016
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Where did you get the data? Personal experience or is there a bmw document referencing boost level vs. IAT/ambient?

I obtained it from a post by Rixt3r or whatever his name was, the P3 vent gauge dude.
 
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impuls

Specialist
Jan 28, 2018
91
57
0
Ride
'07 335i
yesterday I got the engine light on high iddle..
here's the log, this morning :
https://datazap.me/u/hillntoe/log-1522387927?log=0&data=3-5-19

Is the log public? I end up on the datazap start page attempting to view it.

Anyone ? I just want to know if there is a security which open the WG

Many problems will trigger error 3100 - low boost / limp mode. As far as I understand that not directly opens wastegates but targets 0 boost resulting in effectively the same.
 

impuls

Specialist
Jan 28, 2018
91
57
0
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'07 335i
As far as I understand that not directly opens wastegates but targets 0 boost resulting in effectively the same.

Looking at your log... I might be wrong.
Boost target is same, but WGDC is dropping (= WG opens)

Did you read the error codes?
I bet you got a 30FF for not hitting boost target, but is there any other error?
 

impuls

Specialist
Jan 28, 2018
91
57
0
Ride
'07 335i
I don't see anything unusual in the log besides not reaching target boost.

Most likely the dropped WGDC is a security mechanism before triggering limp mode.
Seems PID control is disabled, WGDC follows the base value which should prevent over spinning the turbo in case there is a boost leak.

From what I have been reading the vacuum lines controlling the waste gates are frequently causing the 30FF errors.
Could make sense to visually check those lines before you spend time looking for boost leaks.
 
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