m42 AFM "door" removal ?

[Danny318]

You know how the AFM on the m42 has that swinging trap door type mechanism? Well could someone explain what the point of it is, versus just having a straight through design, like a MAF?

after that,
what would happen if the door was taken out, and is that possible, and has anyone ever done it?

:cool

[thundercat]

i waanna know too

[Viper3812]

I think something bad would happen, idk.

[Tuff Guy]

probably what would happen is too much air would get into your engine at idle and itd screw the whole car up

[Danny318]

Well I thought about it when I looked in the AFM and saw a stupid door. like wtf is the point of this thing?!

And then reading the Miller MAF page, one thing they brag about is it doesnt have the stupid trap door, so its more responsive or something along those lines.

So come on, someone lay it out for us

[Danny318]

probably what would happen is too much air would get into your engine at idle and itd screw the whole car up

uhh, i dont think so. it has a throttle plate at the throttle body that would stop 'too much' air from slamming itself into the engine. not to mention the fancy ICV

[thundercat]

only thing iwant from my m42, is a better throttle responce

[Viper3812]

only thing iwant from my m42, is a better throttle responce

Miller MAF and BBTB/ITB

[Danny318]

yeah but that costs a lot of money. Lets stick to the topic for now...

[Viper3812]

It is a lot, but reliable. We don't know what will happen for sure if you remove the little door from the AFM.

[thundercat]

anyone have a 318 beater?

[Danny318]

We don't know what will happen for sure if you remove the little door from the AFM.

yeah, but im sure someone on here knows or can explain its purpose for being there. Thats what i'm most interested in anyways.

[jimbolina]

Umm, I think that the "door" is what sends the air flow signal to the DME. The other small pendulum looking thing is the air temp sensor.

You can delete the door but only by doing a maf conversion.

[Viper3812]

Umm, I think that the "door" is what sends the air flow signal to the DME. The other small pendulum looking thing is the air temp sensor.

You can delete the door but only by doing a maf conversion.

Thanks for the input.

[Danny318]

hmm can this be confirmed? it does make sense though

[zeit00]

The door measures the amount of air going through it. It uses a series of contacts to send a signal to your ecu (much like how your fuel level sender works) There is a spring that pushes back on the door to keep it closed. Without the door your car will not run (or will run like total crap) You can adjust the spring for a little better responsiveness, but I would not do it if you don't know what you are doing.

[Danny318]

okay, well that certaintly answers the question about removing it :(

Thanks for the info

[zeit00]

okay, well that certaintly answers the question about removing it :(

Thanks for the info

No problem. Its better to ask about these things instead of trying to rip pieces out of the car. ;)

[Ohtwo]

The door type is called a Vane type Mass Air Flow Meter/sensor.

The "normal" type is called a Hot Wire Mass Air Flow sensor.

They both measure the amout of airflow into the engine. Then computer knows how much air enters the engine depending on how much the door moves. Don't mess with the sensor, as they are very delicate and sensitive.

[Danny318]

word, thanks for the info. I'm considering the miller MAF setup a little more now, but dynographs will be what convince me if its worth it or not..

[thedude420]

Umm, I think that the "door" is what sends the air flow signal to the DME. The other small pendulum looking thing is the air temp sensor.

You can delete the door but only by doing a maf conversion.


+1, that door is what makes an AFM an AFM, otherwise it would be an MAF, which doesnt use the old style "flapper door" to measure air flow