# 318D low turbo pressure? Low power



## RamboRaw (Jan 31, 2017)

318D low turbo pressure
Hi guys.

I have an e90lci 318D, N47N, from december 2010. And I really think its missing some power. It doesnt fell like it produces the 143hp its supposed too.

When driving I fell the turbo step in at around 1700-1800rpm and then the acceleration flattens at around 2200rpm, as if the power is constant.

Therefore I checked the turbo pressure, using a OBD reader while driving. The highest boost pressure was around 2,3bar. Which means that the actual pressure produced by the turbo is around 1,3bar - sound low?

Ive tried to find some information regarding what kind of pressure the turbo should be able to produce, and it seems to be around 1,5-1,7bar.

Can anyone confirm this, or have anyone tried measuring the pressure themselves?

Or does anyone now what may be the cause of this "missing power? Furthermore I am having a hard time of getting the car over 20km/l in average. Getting around 18,5km/l on a full tank at mixed driving (though the board computer only gets it to 14km/l). Maybe the problems are related?
Thank you for your help and knowledge!


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## Nadir Point (Dec 6, 2013)

Boost pressure achieved by the turbo(s) is highly variable, dependent on numerous factors, primarily engine load and throttle setting. Saying the turbo is making x amount of pressure is pretty meaningless. The specific conditions under which it makes x amount of pressure might be telling.

Are you asking about the "maximum" pressure potential for your turbo?


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## RamboRaw (Jan 31, 2017)

Thanks for the answer or alilke. 

I am well aware of the factors that influecne the performance of the turbo.

I simply want to know if the turbo is working within the "normal parameters" or if I am missing some power. I hoped someone could tell be some numbers for their car, so I had a reference.

But concerning the "maximum" pressure potential for the turbo, I dont think this is relevant. I dont assume that the stock setup of the car allows for the "maximum" pressure potential of the turbo due to safety/reliabilty issues.


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## Nadir Point (Dec 6, 2013)

RamboRaw said:


> But concerning the "maximum" pressure potential for the turbo, I dont think this is relevant. I dont assume that the stock setup of the car allows for the "maximum" pressure potential of the turbo due to safety/reliabilty issues.


Automotive designers consider the equipment's limitations with regard to the specific unit's efficiency MAP and CFM specs to determine programming, so safety is not issue. Max boost would be whatever the system is designed and coded to produce under full load wide open at sea level.


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## RamboRaw (Jan 31, 2017)

The maximum boost pressure potential for the system has nothing to to with the actual boost pressure available. Several factors are taken into account, and it is made sure that the system will never work at its maximum potential. At that point you are completely wrong. 

But you are missing the point. I hoped that someone on this forum could give me some running numbers so I had a rough idea concerning my turbos condition, not a meaningsless discussion.

Good day to you.


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