[e90Krisztian]

Um so I did something careless.... I installed my euro air box last week and I've noticed sluggish acceleration, which sucks! I keep think what did I do wrong?!!! I checked all the connections and everything is on right, I checked them again and again, every connection, every screw, and I even did an oil change... still sluggish...

BUT I think I know what's going on but I'm not sure, that's why I'm here...

I used the Euro MAF instead of the American spec MAF... ESCTuning's website states, "N52 airboxes come with integrated mass airflow sensors. American market airboxes use a larger, 5 pin mass airflow sensor instead of the 2 pin European connector. You will be reusing your MAF sensor if you have an American market car".... would this be effecting my sluggish acceleration?! What's the difference between a 5 pin and a 2 pin MAF?!!

[3s4u2]

You have to use the Mass Air Flow sensor that came with your original car, this would be the rational explanation to your real issues. You will start throwing codes next if you haven't already.

[e90Krisztian]

Originally Posted by 3s4u2

You have to use the Mass Air Flow sensor that came with your original car, this would be the rational explanation to your real issues. You will start throwing codes next if you haven't already.

Awesome. Would this be the cause of my sluggish responsiveness/acceleration?!

[hurricane56]

I have the euro box as well. You should have just unscrewed the euro MAF from the new airbox and put your old one, the one that came with the car, back into your new euro box.

I don't know the exact technical parameters of the euro MAF, but it is not designed to work in a US spec car. Luckily I have a spare MAF and this nice comparison picture. You need to put the one on the right into your airbox.

[e90Krisztian]

Thanks! the euro air box with the euro sensor has been in my car about a week and I swear I have sluggish acceleration and responsiveness... I'm def going to switch them out as soon as I can, which will be tomorrow morning! I feel so stupid

[Healey3000]

Originally Posted by e90Krisztian

Um so I did something careless.... I installed my euro air box last week and I've noticed sluggish acceleration, which sucks! I keep think what did I do wrong?!!! I checked all the connections and everything is on right, I checked them again and again, every connection, every screw, and I even did an oil change... still sluggish...

BUT I think I know what's going on but I'm not sure, that's why I'm here...

I used the Euro MAF instead of the American spec MAF... ESCTuning's website states, "N52 airboxes come with integrated mass airflow sensors. American market airboxes use a larger, 5 pin mass airflow sensor instead of the 2 pin European connector. You will be reusing your MAF sensor if you have an American market car".... would this be effecting my sluggish acceleration?! What's the difference between a 5 pin and a 2 pin MAF?!!

Hi,

You have to understand what a MAF does and how it works to fully recognize what may have happened when you switched from one to the other.

A MAF measures mass air flow and produces a voltage that is proportional to the mass flow. This proportionality is rarely linear and is based on the King equation. A decent approximation is a third order polynomial. The relationship between mass flow and the output voltage is preprogrammed into the ECU that controls the engine for a given MAF.

If you change from one MAF to another, you have no way of knowing whether the calibration curves are the same or not. Typically, they are not. There are other factors that influence the calibration curve such as the airbox and ducting. Keep in mind that the hot wire sensor is sampling but a small fraction of the airstream through the entire opening and the assumption is that the sample represents the whole. Change the airbox, filter or other elements in the path that can cause turbulence or alter the velocity profile and your calibration is no longer correct.

The correct thing to do is to revert back to the factory MAF, no question about it. Why did you do this swap in the first place? Is the Euro airbox supposed to enhance performance in some way? Remember the basics of MAF calibration - you are changing something rather critical to the proper functioning of the system.

The 5-pin MAF probably has the intake air sensor output brought out separately.

Regards.

[e90Krisztian]

Thank you for your input Healey. I changed my air intake because I was looking at buying a performance air intake however I was drawn away from the bad reviews of aFe and ingen. I also couldn't wrap my mind around spending 800+ dollars for the BMW Performance Air Intake. So, I did my research and found a ton of positive reviews on the euro air box stating that it improves responsiveness and pulls harder around 3grand (which I feel it does do so).. I dropped a k&n air filter in it too thinking it would be a pretty awesome set up and well for over a week I've been pondering as to why I'm sluggish in acceleration. I checked all my connections at least five times and then it hit me. I didn't put my US spec MAF sensor in with the Euro air box....

[Cuba]

you quoted the solution to your problem in your original post... switch the sensors

[3s4u2]

Change it back to the original MAF sensor and I think you will find that all is good once your complete.

Nice explanation Healey3000..., he would have a digital MAF (09/2006 and up) with a NTC thermistor with a 5 volt reference from the ECM.

[e90Krisztian]

Originally Posted by 3s4u2

Change it back to the original MAF sensor and I think you will find that all is good once your complete.

Nice explanation Healey3000..., he would have a digital MAF (09/2006 and up) with a NTC thermistor with a 5 volt reference from the ECM.

Translation... & why does the euro air sensor in my euro air box negatively effect the vehicle?!

[Dr.GumbyM.D.]

Originally Posted by e90Krisztian

Translation... & why does the euro air sensor in my euro air box negatively effect the vehicle?!

he would have a digital MAF (09/2006 and up)

Your sensor is digital (the euro may be analog?) I don't know why that's relevant, but that's what it sounds like?

with a NTC thermistor with a 5 volt reference from the ECM.

The US MAF includes more than just the air flow sensor, it sounds like it includes a thermistor (another name for thermometer), probably so that it can change air/fuel mixture based on intake air temperature (think about why people install CAIs, to minimize the temperature of incoming air). The 5v reference is likely not of interest to you, but it's just saying what the voltage run through it (and it modifies, sending that modified signal to the ECU for interpretation and adjustment of fuel/air mixture).

The point is, the European MAF may or may not include the thermometer, and regardless, it may or may not be on the same voltage (sounds like it isn't) as the US spec one, meaning that if your US MAF gives the ECU 4v indicating a certain volume of air incoming to the engine, the EU spec one may give 3v or something (these are all made up numbers to try to help explain what you asked for explanation of why they matter). So if your ECU, programmed for a 5v US MAF receives a 3v signal from the EU MAF for the same temperature and same volume of air, then your car will under perform, because your ECU is reading that the engine is not receiving enough air, so it's reducing performance to make sure it doesn't flood your engine with fuel when there is no air.

TLDR: The EU MAF gives different voltage, ECU programmed for higher voltage, expecting US MAF, sees less air going into car, reduces performance accordingly.

[Healey3000]

Originally Posted by 3s4u2

Change it back to the original MAF sensor and I think you will find that all is good once your complete.

Nice explanation Healey3000..., he would have a digital MAF (09/2006 and up) with a NTC thermistor with a 5 volt reference from the ECM.

Thanks! If indeed the Euro one has an analog output and the US one has a frequency output, it gets even more interesting. A lot of cars use a MAP sensor as a backup or for WOT conditions. It could be that the car saw an error on the MAF input and switched over to a speed-density fueling table. That would explain the sluggishness but I would expect an SES light to come on.

Anyone know whether the E9x has a MAP sensor?

Regards.

[3s4u2]

Originally Posted by e90Krisztian

Translation... & why does the euro air sensor in my euro air box negatively effect the vehicle?!

e90Krisztian,

Looks like you have had some good explanations to your questions; basically the MAF checks the air temperature/flow into your engine and provides that information to the ECM (BMW term-"Engine Control Module"), then the ECM provides the means for your fuel, injectors, spark, timing etc…
Please review the attached PDF that was located on WIK...

I was just wondering if you have had a chance to switch the MAF’s, and if so let us know your progress, good or bad.

[3erdriver]

so if you need to swap the MAF it needs to be programed or if it's being swaped with the same part number you can just swap it?

[juld0zer]

The Euro 'MAF' is not a MAF sensor. It's purely an IAT sensor, hence only two pins. I'm not too familiar with the rest of the Euro engine but i imagine there would be a MAP sensor on the intake manifold and the DME uses that to determine air quantity.

From memory, MAF equipped N52s also have a MAP sensor at the rear of the intake manifold