Technical Feasability

[peerless]

I would like to now if any one has any resources for what it takes to use a MAF system.

I dont want to buy one from somebody I am looking to brew my own setup.

From the way I see it I would just need to convert the MAF signal to a signal the stock Motronic would understand and make correct fuel calculations.

Any Ideas?

Robert
85' 325e

[nando]

it won't work without an aftermarket computer or piggy back to convert the signal. an SMT6 unit can handle the task and you can pick up an E36 328i MAF cheap. do a search, there was a big discussion on this topic a couple weeks ago.

[peerless]

Thats the point, I don't want it to be some expensive aftermarket SMT-6. I want to have a converter hardwired to the MAF itself. This gives a nice bolt on performance upgrade for a lot less money and hassle then purchasing a seperate computer and trying to figure out how to program it completly from scratch. I want this to basically be a stock replacement for the AFM. This is why I am trying to get details about what signal the MAF generates as compared to the AFM. With a converter hardwired and attached to the MAF using the same stock conector if possible.

So I assume the MAF generates a digital voltage output to the ECM and the AFM sends an Analog signal. So I would need to convert it and also make sure that it is sending a reading that directly corresponds to what the computer is expecting to see from the AFM.

It would also be nice if I could incorporate a "trim adjustment" as well for fine tuning. Eventually building a complete performance bolt on kit that would include the MAF and cold air intake system.

This really comes down to somewhat basic electronics. I just need info on where I might find technical electronic specs for both units.(MAF & AFM)

Also on the subject of a seperate computer, I have been bouncing around the idea of using a embedded Llinux system. Including an optional in-dash LCD readout display provided live data feed from the ECM itself.

No how much would you pay? But wait theres more, if you order in the next 20 minutes we will also throw in a bottle of Nitrous

Any thoughts???

Robert
85' 325e

PS: Those Krinkle finish M20 valve covers everybody wants. I plan on workng that idea too. I heard IE was charging $175 or $275 for those things. RIP. How about anodized vavle covers, any interest in those???

[nando]

sorry, it's just not going to happen. not cheaply, anyway.

[peerless]

I don't mean to toot my own horn but I have a degree in automotive technology as well as a degree in computer network engineering. I not only know this can be done I am going to do it. Like I said its basic electronic signal processing. A bit of Reasearch and Tenacity and I will be selling them and you will be buying them.

:twisted:

[m42technic]

I don't mean to toot my own horn but I have a degree in automotive technology as well as a degree in computer network engineering. I not only know this can be done I am going to do it. Like I said its basic electronic signal processing. A bit of Reasearch and Tenacity and I will be selling them and you will be buying them.

:twisted:

If it were as easy as you believe it is, then someone would have done what you are planning long ago.

[808BMW]

PS: Those Krinkle finish M20 valve covers everybody wants. I plan on workng that idea too. I heard IE was charging $175 or $275 for those things. RIP. How about anodized vavle covers, any interest in those???

Doing valve covers is hard because your car has to sit there with no valve cover while we ship it, you clean/paint it, then ship it back.

I posted about anodizing valve covers, didn't get too great feedback on that one though :P

[peerless]

I got the specs for the Ford Mustang V-8 MAF. I think 55mm bore size should be a huge improvement over the stock AFM.

Anyways heres the link for the voltage/airflow readings and pin outs.

http://www.dainst.com/info/maf/ford_mustang_maf.html

Voltage Flow (kg/hr)
4.76807 835.509
4.44312 695.465
4.17700 595.977
3.88599 499.658
3.54395 399.219
3.35498 347.574
3.14893 295.612
2.90991 243.334
2.69409 201.828
2.58203 182.500
2.44995 161.272
2.31592 142.261
2.15405 120.083
1.98901 100.122
1.88989 90.2996
1.80298 82.3786
1.69092 72.8734
1.57397 62.4176
1.46802 54.1798
1.32104 44.6745
1.18188 36.7535
1.09106 32.6346
0.884033 23.7631
0.75000 18.6936
0.571045 13.6242

Ford Mustang MAF pinout (oval 4 pin connector)
Pin Function
A VPWR (switch 12 volts)
B GND
C MAF RTN (MAF signal ground)
D MAF SIG (MAF output signal)

NOTE: The Ford Mustang MAF sensors has 4 pins, denoted by A B C D on the sensor case.

Ford MAF pinout (rectangular 5 pin connector)
Pin Function
A VPWR (switch 12 volts)
C GND
D MAF RTN (MAF signal ground)
E MAF SIG (MAF output signal)

NOTE: The rectangular connector MAF sensors have 5 pins denoted by A C D E, with the B pin missing.

Ok now I need the information for the stock AFM. The Mustang MAF lacks an airtemp sensor. I assume this because it is not listed in the pinout specs. So a seperate airtemp sensor needs to be placed in the airstream. Will need to use an ntc type. I will need the specs for the stock AFM as it has this feature built in to the unit.

The stock afm reads resistance if I am correct. So I will need to somehow convert
a voltage reading to a resistance reading. hmm. This is going to be fun:-)

[m42technic]

The stock afm reads resistance if I am correct. So I will need to somehow convert a voltage reading to a resistance reading. hmm. This is going to be fun :-)

Ohm's law.

[Rob]

sounds good in theory, I'd like to see you make it happen, if for no other reason than to suprise people

[peerless]

Ok I got more information. Sorry I'm bored and brainstorming.

AFM info is kinda vague right now as I am refering to the Bentley.

You have 4 pins on the early AFM. 5,9,7,8 .
Bentley says for the door resistance use pins 7 and 8. To check air temp use pins 8 and 9.
They dont mention pin 5 which of course must be switched 12V. Also I will assume that pin 8 is the common ground.

But of course there is no resistance values given for the vane. At least they say that the air temp resistance should be 2200-2700 at 68deg.F. To integrate the seperate MAF and Air Temp sensors they will both have to tie into pin 8 for the ground.

Lets compare the two pin outs:
AFM;
Pin 5 = 12V
Pin 9 = Air Temp Resistance
Pin 7 = Vane Resistance
Pin 8 = Common Ground
MAF (Mustang V-8)
Pin A = 12V
Pin B = Ground
Pin C = MAF RTN (MAF signal ground)
Pin D = MAF SIG (MAF output signal)

The problem I see here is that the MAF uses 4 wires without air temp incorporated.
So can Pin C on the MAF use Pin 8 on the AFM. I am thinking so. Pin B could be just a common frame ground. So Pin A to Pin 5, Pin B to frame ground, Pin C to Pin 8,
Pin D to Pin 7, and Pin 9 gets its signal from a seperate Air Temp Sensor.

Now we just need to find a way to convert the voltage value to a resistance value that the ECM can understand. I am thinking a good electronics store would be helpful for this task. Anyone here know what it takes to convert these signals.

Cool,

Robert
85' 325e

[peerless]

PS: Those Krinkle finish M20 valve covers everybody wants. I plan on workng that idea too. I heard IE was charging $175 or $275 for those things. RIP. How about anodized vavle covers, any interest in those???

Doing valve covers is hard because your car has to sit there with no valve cover while we ship it, you clean/paint it, then ship it back.

I posted about anodizing valve covers, didn't get too great feedback on that one though :P

I planned on buying a grip of used ones and get them hot tanked, painted, clear coated and in stock ready to sell. You just simply replace yours with the new one.

[peerless]

Hmm. Found some conflicting information using BMW Electronic Troubleshooting Manual.

It say the ECM pinouts are different. The BMW manual says:
Pin Function
7 Reference output to the AFM.
8 Common ground.
9 AFM input signal
22 Air Temp signal

Ford Mustang MAF pinout (oval 4 pin connector)
Pin Function
A VPWR (switch 12 volts)
B GND
C MAF RTN (MAF signal ground)
D MAF SIG (MAF output signal)

Hmm some one the car measurements are in order here. I dont have a multimeter anymore. I will have to dig one up somewhere.
Also how do I post PDF snapshots??

Robert
85' 325e

[JRowe]

I think you have a great idea and would like to see you succeed. Don't listen to the doubters. More power to you if you can do it.

My recommendation would be to search this site for all posts dealing with this topic. It has been beat to death, and you could get alot of info (who knows how reliable) about it. Also, this topic was discussed ad naseaum on the bmw e30 network forum( www.bmwe30.net ). Do a search through their archives also. Good luck let us know how it works. If it does, I'd be in line to buy one for a reasonable price.

[E30godz]

i thought the AFM was 0-5 volts? its that or somewhat in between