NorCal90

When I was installing my HKS intake today I noticed a plastic cone shaped piece inside the filter side of my MAF that was spring loaded. What is it and what purpose does it serve? Also, can it be removed for better flow or is that not a good idea?

RotorDemon20B

LOL.. That is the sensor. You wont be driving far if you remove it. or even get it out of the driveway.

therotaryrocket

I thought the S5's sensor was less restrictive?!?!?? Maybe you can upgrade to the s5, unless your car is an s5 and im just dumb.

gxlbiscuit

<---throws his mouse at you......... dont tear up your lovely seven:-P

NorCal90

Whoops, my bad guys. lol I didn't realize that was an important part of my MAF. I thought it was just some sort or factory jackassery to limit emissions or quiet it or something.

casio

whenever you test your afm, you can hook up a voltmeter (to the proper wires) and move the cone in and out to test your volt readings. its a necessary part of the sensor (s5). s4 is a flapper which i've never seen the inside of.

YearsOfDecay

It IS less restrictive.. dude... The S4 MAf has this L shaped friggin door that swings back and forth... it REALLY sucks!!

RETed

It's a myth that the S5 AFM is less restrictive.
I haven't seen any solid proof it is.
If anything, the S4 is less restrictive, since the airflow shoots straight through the AFM, even with the swinging door.


-Ted

Tofuball

My S5 AFM will be the least restrictive!

Sitting on a desk and not in my car!

Dont get any ideas and start drilling 'flow holes' in your AFM now

NZConvertible

Do you actually have any evidence of this or is it just an assumption? At full deflection the S5 AFM still has the measuring cone in the air path; the S4 has nothing in the way. The S5 AFM's inlet has a cross-sectional area of ~27cm2; the S4's is ~31cm2 (~15% bigger). Can you explain how the S5 AFM flows better despipte these two facts?

rs_1101

dont worry.. youre not missing much..

rs_1101

now i would theorize that since the s5 is an advanced version of the s4 system, that mazda would implement the cone for a reason. now its definitly more symetrical, but flow wise.. good question right? in basic flow, the circle would cause more turbulence to the rear of it, as opposed to a flat flapper, however, lets consider the 100% throttle condition (which is our favorite right?) at 100% its like... what flapper? it folds back for a straight through flow.
at 100% the ball is still there. so that would lead me to hypothesize that mazda redesigned it for partial throttle gas mileage (also note on s5 mazda included wide range tps)
could i be right?

NZConvertible

Far more likely is that it was cheaper to manufacture and gave a more linear signal (which would be of no advantage without the S5's ECU).

kenn_chan

right or worng I know not, but around here my JN friends say it was because the flapper style wasn't very accurate do to the fact that it tends to "bounce" ? like I said right or worng I don't know thats just what they claim,

kenn_chan

Tofuball

Mazda claims it was less restrictive in the FSM. It is circular as opposed to square.

I dont know personally if it is less restrictive, but that is what I know.

NZConvertible

Um, in case you misread the posts Ted and I agree on this point.

Syonyk

With a stock intake & exhaust system, how "wide open" does the S4 one get? I suspect it doesn't hit 100% open, or there would be nothing "left" to deal with the increased airflow of cone filters & exhaust & such.

-=Russ=-

Kingofl337

Is there a converter to hotwire style maf?

rs_1101

i dont think you can.. hotwires would work in a reverse voltage right?... no thats not right at all.. maybe... look around for a hotwire with a similar voltage range. but it really depends on if the hotwire is linear like the MAF sensor.

RETed

Can you give us reference to such?


-Ted

NZConvertible

89 FSM pages F1-82 and F2-80: "The sliding type airflow meter is superior to others in that it moves easily and causes minimal air resistance."

However it doesn't take a rocket scientist to see that this is actually very unlikely, for the reasons I stated above. Anyone with proof of an advantage either way is more than welcome to post. The only back-to-back dyno testing I've ever heard of resulted in a whopping 2kW advantage with the S5 AFM, but this tiny amount could just as easily be attributed to numerous other factors like the probable mixture changes caused by the swap or a change in air temp.