Maf sensor

[laloosh]

has anybody actually taken out the maf sensor and looked at it?

There are two wire with a lil browinsh ball. next to that lil ball is a much bigger piece of useless plastic with a hole going through it. What the hell is the point of the maf being shapped the way it is? What the point of that piece of plastic with a hole through it. ive seen of a ton of nissan mafs and they actually looked like everything served a purpose, our mafs look universal and things are just there for the hell of it.

 

[bova80]

like this? or did you take it apart father?

 

[Jays07MS3]

EDIT: beat me to it And yeah, one is the IAT and up inside the sample tube is the MAF sensor.

 

[laloosh]

 

[bova80]

i broke that plastic piece next to the IAT bulb taking it out of the stock airbox. i dont think it did anything just exposed on the side.

 

[Mid_Life_Crisis]

EDIT: beat me to it And yeah, one is the IAT and up inside the sample tube is the MAF sensor.

So the purpose of the hole is that the sensor works off of a venturi effect? The air rushing through the bottom of the tube is detected by the sensor up inside?

 

[laloosh]

yea i dont really see how the air is going to throug that hole, up the sensor, through the sensor, downt he sensor and out the other end. Does this seem wierd to any1 else but me?

 

[sleeper3]

I am not 100% sure but I think the MAF sensor is more concerned with air DENSITY. air flow over the sensor is probably limited to diminish the effects of air flow over the sensor to lower the error in the reading.

 

[bova80]

because on the front side it hits what is like a wall then goes up and is pulled back down from the vacuum that is created.

 

[Mid_Life_Crisis]

yea i dont really see how the air is going to throug that hole, up the sensor, through the sensor, downt he sensor and out the other end. Does this seem wierd to any1 else but me?

You're too young to have ever had to rebuild a carb, so you weren't forced to learn about venturi effects the hard way. If you have a small opening, and air blows past it, it will pull air through the opening. I don't have a sensor in front of me, but from the other posts, there appears to be an opening at the top of the tube, so when air flows through that circle at the bottom, it creates a vacuum in the tube so that air is pulled down the tube and across the sensor inside it. How much air is in direct proportion to the amount of air flowing through the circle. By pulling the air past the sensor in this fashion instead of blowing it across it, they probably get a more linear, precise reading from the sensor due to the reduced turbulence.

Edit: plus the sensor is enclosed and protected.

 

[bova80]

i learned about good ol' venturi in physics

 

[Jays07MS3]

You're too young to have ever had to rebuild a carb, so you weren't forced to learn about venturi effects the hard way. If you have a small opening, and air blows past it, it will pull air through the opening. I don't have a sensor in front of me, but from the other posts, there appears to be an opening at the top of the tube, so when air flows through that circle at the bottom, it creates a vacuum in the tube so that air is pulled down the tube and across the sensor inside it. How much air is in direct proportion to the amount of air flowing through the circle. By pulling the air past the sensor in this fashion instead of blowing it across it, they probably get a more linear, precise reading from the sensor due to the reduced turbulence.

Edit: plus the sensor is enclosed and protected.

Exactly. Air rushing past an orifice produces a vacuum which draws air through it. That way it probably sees a more laminar flow than if it was directly exposed to the air stream.

 

[bova80]

like so

edit: assume the air is being pulled through, which if you know how a vacuum works would understand that already.

 

[Mid_Life_Crisis]

like so

I know what you were trying to demonstrate, but the uninitiated could easily look at that drawing and assume that the air is being forced into the tube instead of drawn through it.

 

[sleeper3]

Exactly. Air rushing past an orifice produces a vacuum which draws air through it. That way it probably sees a more laminar flow than if it was directly exposed to the air stream.

that is a much more elegant way of saying it.

 

[laloosh]

i understand they thoery. i own a carb quad and rejetted it tons of times so im not a complete nub when it comes to carbs. however i was aslo told air takes the path of least resistance, weather it be sucked in or pushed out. i just dont see why mazda would do something like this? The only logicl reason would be if something bigger got sucked in, a pebble or something or a lil gravel that could possible damage the sensor if it was in direct flow. What other reason would they have for hiding the sensor like that?

 

[Mid_Life_Crisis]

i understand they thoery. i was aslo told air takes the path of least resistance, weather it be sucked in or pushed out. i just dont see why mazda would do something like this? The only logicl reason would be if something bigger got sucked in, a pebble or something or a lil gravel that could possible damage the sensor if it was in direct flow. What other reason would they have for hiding the sensor like that?

The air filter should prevent that. As I said before, by drawing the air over it in a controlled path, the airflow is smoother, which probably gives them a more accurate reading.

 

[laloosh]

the maf housing itself, with the fins, is a controlled path

 

[bova80]

if you notice the path up to the maf sensor it is expose so the air comes in and basically like hitting a wall at that point above the circular pass thru, which is used to generate the vacuum to bring the air back down from going over the maf sensor. you say air takes the least path of resistance but there is no real resistance there as the vacuum helps pull the air up and through that part. hope that makes sense, if you didn't understand it already.

 

[redrocketz]

what kind of MAF is it? is the real question. I assume it's hot wire in which case they don't want it fully exposed because it is a very delicate little wire. If you look at different MAF's there are some really unique looking ones out there.