# Why MAF is so expensive?



## Boile (Jul 5, 2005)

Dealer wants $350 for a mass airflow sensor. That's the part only, not including labor.
I took it out to clean it. It's an empty plastic shell, with a mesh on each end and a metal filament (the sensor) in the middle of the housing.
Why does it cost so much? Did I look at the wrong part? :dunno: 
My cell phone has a lot more electronics and research put into it, and costs a third of that.


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## Moderato (Nov 24, 2003)

Boile said:


> Dealer wants $350 for a mass airflow sensor. That's the part only, not including labor.
> I took it out to clean it. It's an empty plastic shell, with a metal mesh on one side and a filament in the middle.
> Why does it cost so much? Did I look at the wrong part? :dunno:
> My cell phone has a lot more electronics and research put into it, and costs a third of that.


Although it looks like nothing more then a cheap piece of plastic, it is actually one of the more important parts because it directly effects engine performance. $350 is expensive, but I think that is about the going cost of that part from any manufacturer.


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## Boile (Jul 5, 2005)

Moderato said:


> Although it looks like nothing more then a cheap piece of plastic, it is actually one of the more important parts because it directly effects engine performance. $350 is expensive, but I think that is about the going cost of that part from any manufacturer.


Your comment is welcome, although it does not address the question.
I don't think parts are charged based on their importance to the car.


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## cwsqbm (Aug 4, 2004)

Boile said:


> Dealer wants $350 for a mass airflow sensor. That's the part only, not including labor.
> I took it out to clean it. It's an empty plastic shell, with a mesh on each end and a metal filament (the sensor) in the middle of the housing.
> Why does it cost so much? Did I look at the wrong part? :dunno:
> My cell phone has a lot more electronics and research put into it, and costs a third of that.


Reasons it is more expensive than your cellphone:
1. Your cellphone is sold to you at a loss so that the company can make the money off the service. This part, on the other hand, is proabably a standard dealer markup on parts and then there's BMWNA's markup to the dealer, etc.
2. The metal filament and other parts are made to very high precision because the calibration of the sensor greatly determines how well the car runs and whether it does well on emissions and mileage tests.

The price seems in line with what other manufacturers charge.


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## Penforhire (Dec 17, 2005)

At least we can give some concrete reasons why, guys.

The filaments are likely platinum. The way modern MAF's (mass air flow) work is by using Pt as thermistors (temperature sensitive resistors). The electricity required to maintain a very exact temperature/resistance across the wires, arranged in a sensitive bridge circuit, can be translated into air flow across those wires (more flow = more cooling = more current required to maintain wire temperature or resistance).

Notice the three electrical connectors going into a box-like cavity? There is normally a very sophisticated hybrid electronic module in there to perform this task and communicate with the ECU. How sophisticated? The one whose design I examined to reproduce (a GM model) was "state of the art" with flip chip BGA's and densely packed three mil line & space traces. And there is probably individual MAF sensor calibration required.

And, last-but-not-least, there is a big mark-up on retail automotive parts. The costs of warehousing are greater than you imagine and auto makers do make large margins on part sales. To give you an idea, the parts my company sells to automotive OEM's cost you, at parts counter retail, about 10x our selling price to the OEM.

I'd bet whoever makes this $350 MAF (maybe Bosch?) sells it to the OEM for $40 to $50.


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## Boile (Jul 5, 2005)

Good answers so far. Keep them coming.
I can think of many other parts with a lot more technology behind and possibly more difficult to produce, that are much cheaper than this MAF.
For example, a light bulb. It's got a filament, it's tungsten (not too behind platinum), has to resist extreme temperature and vibration, the enclosure has to be properly sealed to hold either vacuum or some esoteric gas (contrast with the simple plastic shell in the MAF), and yet it costs 1/100 of the price.
I'm not saying BMW MAF is expensive. The question is generic. Why MAFs are so expensive? What makes it so?
The mentioned dealer markups are valid points, but they apply to all parts, not just MAF.


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## Salvator (Oct 14, 2003)

Boile said:


> I'm not saying BMW MAF is expensive. The question is generic. Why MAFs are so expensive? What makes it so?


My guess is the MAF for each car is specific to that car / engine type... AFAIK, there is no source for a generic MAF. BTW, the MAF for my '96 Land Rover Discovery is $700, so by comparison, BMW is cheap!


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## HW (Dec 24, 2001)

Boile said:


> Good answers so far. Keep them coming.
> I can think of many other parts with a lot more technology behind and possibly more difficult to produce, that are much cheaper than this MAF.
> For example, a light bulb. It's got a filament, it's tungsten (not too behind platinum), has to resist extreme temperature and vibration, the enclosure has to be properly sealed to hold either vacuum or some esoteric gas (contrast with the simple plastic shell in the MAF), and yet it costs 1/100 of the price.
> I'm not saying BMW MAF is expensive. The question is generic. Why MAFs are so expensive? What makes it so?
> The mentioned dealer markups are valid points, but they apply to all parts, not just MAF.


the "flip chip BGA" :dunno: but i have no idea how many transistors are in this IC used in a MAF though. maybe just your everyday embedded processor doing some table lookups. but calibration may be expensive to do.


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## ProRail (May 31, 2006)

Boile said:


> Dealer wants $350 for a mass airflow sensor. That's the part only, not including labor.
> I took it out to clean it. It's an empty plastic shell, with a mesh on each end and a metal filament (the sensor) in the middle of the housing.
> Why does it cost so much? Did I look at the wrong part? :dunno:
> My cell phone has a lot more electronics and research put into it, and costs a third of that.


Volume.


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## Penforhire (Dec 17, 2005)

You are mistaken thinking a lightbulb is similar in complexity to a MAF sensor. The light bulb is probably made in about six steps (and uses dirt-cheap tungsten wire), has 99+ % yield, and costs the manufacturer maybe a nickel. I don't engineer lightbulbs but I do deal with some other parts that we sell for pennies (chip resistors, low-end trimming potentiometers). We can only sell stuff that cheaply if the material content is dirt cheap and the process is highly automated (trimming pots) or done in very large arrays (chip resistors).

MAF yield is nothing to brag about. The super-fine-line printing (to squeeze so much in a small package), many layers, and tight assembly (nasty crap like 0402 size chips) makes that hybrid a biatch. A lower-tier automotive parts manufacturer is always squeezed hard for margins so that MAF sensor must cost $25+ to manufacture in high volume and parts may be the bulk of the cost, except for calibration. Platinum isn't cheap and neither are the silver, gold, and silver-palladium alloys used in the hybrid traces and connections (even with design for minimum use). Calibration is automated but the individual unit handling and time-to-program still costs a chunk. The assembly automation can be staggering (multiple-million-dollar machines) so labor content is no big deal but we still want a pay-pack for those machines, right?

The plastics used in underhood applications need to withstand significant heat (say when you shut off the engine on a hot day), be mechanically strong (crack & creep resistant to vibration, mechanics dropping them,...), and resist ALL automotive solvents and other liquids it may contact (brake fluid, tranny fluid, gas, sulfurous gasses, diesel, oil, Coca Cola,...). So that big plastic housing costs more than it could if it were intended for a less demanding environment (home "white goods"). I really like glass-filled Amodel (or DuPont's HTN) for its cost versus strengths but it can't be used for everything (tends to warp, can crack on impacts or if over-compressed with a nut, noisy if it rubs against itself, streaky colors,...).

Oh, and that hybrid has to be sealed or potted to withstand the same abuse. Otherwise the cheap silver traces they use the most to reduce cost will migrate (short out) under biased moisture conditions and you'll be buying another MAF sensor.

If the littlest thing gets changed (sometimes if I just want to move a piece of equipment across the floor!) it has to be re-qualified by an expensive PV (Production Validation) and PPAP (production parts approval process) that includes not only life testing and revision of a pile of documents (e.g. PFMEA, DFMEA, Control Plan...) but, worst case, may also require fleet testing in automobiles. Holy cow is THAT expensive!

So I'd gladly make you a lightbulb for a lot less than a MAF sensor.

And a related FYI - I like K&N style filters as much as the next gear-head but if you over-oil them the lube can move down the intake, cover the MAF sensing wires, and you get to buy a new MAF sensor (again). You may notice MAF sensors often placed after a tubing bend to reduce the chance of something like this but it doesn't always do the trick.


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## Bruce (Dec 24, 2001)

Salvator said:


> My guess is the MAF for each car is specific to that car / engine type... AFAIK, there is no source for a generic MAF. BTW, the MAF for my '96 Land Rover Discovery is $700, so by comparison, BMW is cheap!


Definitely not specific. The MAF for the E39 M5 is te same as the one for the VW 1.8T engine. There are guys that are buying the VW part and taking out the filament and swaping it over to the M5 housing. Unfortuantely the MAF on the E39 M5 appears to be a wear item that needs to be replaced every 50k miles or so.


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## HW (Dec 24, 2001)

Bruce said:


> Definitely not specific. The MAF for the E39 M5 is te same as the one for the VW 1.8T engine. There are guys that are buying the VW part and taking out the filament and swaping it over to the M5 housing. Unfortuantely the MAF on the E39 M5 appears to be a wear item that needs to be replaced every 50k miles or so.


are people using kn type airfilters :dunno: the oil from those will contaminate maf's


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## Bruce (Dec 24, 2001)

HW said:


> are people using kn type airfilters :dunno: the oil from those will contaminate maf's


Yes and no. Yes, some people are and that is hastening the issue. No, not are people are and they are still having issues. The problem is when the MAF goes bad it leans out the mixture....lean mixtures go BOOM.


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## Moderato (Nov 24, 2003)

Boile said:


> Good answers so far. Keep them coming.
> I can think of many other parts with a lot more technology behind and possibly more difficult to produce, that are much cheaper than this MAF.
> For example, a light bulb. It's got a filament, it's tungsten (not too behind platinum), has to resist extreme temperature and vibration, the enclosure has to be properly sealed to hold either vacuum or some esoteric gas (contrast with the simple plastic shell in the MAF), and yet it costs 1/100 of the price.
> I'm not saying BMW MAF is expensive. The question is generic. Why MAFs are so expensive? What makes it so?
> The mentioned dealer markups are valid points, but they apply to all parts, not just MAF.


Let me make this very clear for you: THE MAF ISN'T EXPENSIVE!


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## Salvator (Oct 14, 2003)

Bruce said:


> Definitely not specific. The MAF for the E39 M5 is te same as the one for the VW 1.8T engine.


Interesting... so one would think, even with Penforhire's description of the requirements necessary, that a "generic" MAF "could" be made... wonder why no one has? :dunno:


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## Jalli (Jan 10, 2005)

Sure, you could make a generic MAF, it seems to me from what I have read in this thread that an MAF is an MAF... BUT the plastic housing would surely be different for each car, as would the software, progrmamming etc... 

Hey if you want to start a company to manufacture generic MAF sensors and housings go right ahead. Just all the money you will need from someone other me. Just think about it.. studies, loan proposals, techinical schematics, plant startup costs, vehicle testing, govt and industry certification... we are talking about serious money...

Doesn't really matter, it will probably never happen. I think the MAF is pretty much regarded as a wear itm by many people now..


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## Penforhire (Dec 17, 2005)

I think everyone programs their ECU differently so the actual signal from the sensor varies. Also different sized engines require different sensor designs (big-flow sensor is not accurate in a small-flow engine). Also the plastic housing is sometimes molded to fit around an engine packaging issue. I know companies try to reuse the MAF's as much as possible.


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## Salvator (Oct 14, 2003)

Moderato said:


> Let me make this very clear for you: THE MAF ISN'T EXPENSIVE!


Sure... in the grand scheme of things it isn't... but when you are in the situation I am, where I wish to sell my '96 Land Rover Disco (street value, about 5K) and it won't idle and a new MAF costs $700 (i.e., almost 1/5th the value of the car, once I add in installation labor) it becomes quite expensive... fortunately, it turned out not to be the MAF, but the Idle Stepper motor instead... by the time I paid full price and labor for that, it was $450, so that's only about 1/10th the value of the car. :rofl:


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## Andrew*Debbie (Jul 2, 2004)

Why are any of these parts expensive? My e34 needs a front shock mount *again.*

This $120.00 part doesn't have any electronics in it at all. No calibration. Just a bit of 'rubber' and metal.

Warehousing and markup have a lot to do with it.


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## Moderato (Nov 24, 2003)

Salvator said:


> Sure... in the grand scheme of things it isn't... but when you are in the situation I am, where I wish to sell my '96 Land Rover Disco (street value, about 5K) and it won't idle and a new MAF costs $700 (i.e., almost 1/5th the value of the car, once I add in installation labor) it becomes quite expensive... fortunately, it turned out not to be the MAF, but the Idle Stepper motor instead... by the time I paid full price and labor for that, it was $450, so that's only about 1/10th the value of the car. :rofl:


Yeah that's true. I really ment to "relatively." The MAF part as essential as it is, isn't really expensive relative to other essential repairs & parts on a car. The OP seems to be having a hard time understanding why the MAF is expensive, but so is everything else on a car you can't do for yourself or buy somewhere else. It's called RETAIL. That's how businesses make money, by charging way more then something is really worth, and that's called PROFIT. I'm sure it didn't cost BMW 40K to make the average model 3 series so I'm not going to start complaining about the cost of a MAF. Especially when the price BMW charges is in-line with every other car manufacturer. Why does this thread exist again? uch:


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