Author Topic: M3 Airflow meter swap (Read 5578 times)

92E36 · « **on:** July 09, 2009, 05:48:06 AM »

Hi There, I have a 92 E36 318IS M42. I am trying to swap my standard airflow meter with a 1999 M3 air flow sensor. My current sensor has a 5 wire sensor and the M3 is a 4 wire sensor. Could anyone help me with wiring instructions for this swap.your help would be much appreciated.

thanks

Boyracer · « **Reply #1 on:** July 09, 2009, 06:25:52 AM »

You can stop right there because swap does not give practically any gains and it requires lots of work with electronics to adapt new MAF to old car. This idea has been tried before here and the conclusion was that it is not worth it at all.

92E36 · « **Reply #2 on:** July 09, 2009, 11:51:57 PM »

The car is going to be turboed so that why i was going to install the maf sensor

1991 E30 M42 · « **Reply #3 on:** July 10, 2009, 02:11:02 AM »

if your gonig to go through all that trouble, why are you going to use a maf, go map and you will have no airflow restrictions and everything supports a GM 3 bar map sensor

92E36 · « **Reply #4 on:** July 10, 2009, 06:36:43 PM »

ok you guys will have to help me here. How do i do that? Im a little bit new to the BMW side of things.

DesktopDave · « **Reply #5 on:** July 10, 2009, 06:43:11 PM »

It's not about BMW. He's talking about the different types of intake air sensors. We usually have the really old flap-style AFMs. They measure air by pushing a door open. Next up is the new style hot wire MAF. This senses air pressure directly with the resistance of a heated wire. Both those have a sensor in the airflow, thus creating a restriction. You can avoid it by installing a manifold air pressure sensor...no upstream sensor=no restriction. Get it now?

92E36 · « **Reply #6 on:** July 10, 2009, 11:38:08 PM »

yep i get it thanks. Where can i get an air pressure sensor and can you guys help me with wiring instructions. Thanks

92E36 · « **Reply #7 on:** July 14, 2009, 05:06:34 AM »

can you guys help me or not?

?

1991 E30 M42 · « **Reply #8 on:** July 14, 2009, 06:15:53 AM »

how are you going turbo your car if you cant wire up a map sensor? Just search GM 3bar MAP on google and you'll find a wiring diagram. Its only a 3 wire connection, power ground and sensor im sure

92E36 · « **Reply #9 on:** July 22, 2009, 02:50:16 AM »

ok. All in all my question has not been answered. Can anybody help me with wiring instructions to install a 99 M3 airflow sensor into a 92 e36 318IS.

Deftones · « **Reply #10 on:** July 22, 2009, 03:05:40 PM »

you cannot adapt it without making yourself (there isn't anything similar in commerce) a very complicated elecronic device(there isn't anything similar in commerce)...
basically your flap type afm moves a resistance: simply more air in-> more resistance and so your engine knows how much air is entering. The M3 afm, which is a hot wire type so it is a maf, uses a thin wire which is being heated by a current measured by the ecu to keep it 180�C above air temp and so the engine know how much air is entering. Much air enter-> more current needed to heat the wire.

So, if you have to do an adapter you have to do a circuit which calculate the current and convert it into a resistance value which can be readed by your ecu... i think this is much more complicated than spending 200$ for a megasquirt which can manage well all your engine, from ingnition to injection, it is programmable by a pc and can work with your afm, the m3 maf and also with the manifold pressure sensor, so without any restriction!

ps:if you're going to turbocharge for less than 300hp your flap type afm can works well!