MAF Converter...99% READY TO ROLL!

[bmwman91]

Haha yeah.  It likes to sit in the back of my mind, working itself over.  I will usually be sitting at the dinner table talking about whatever, when suddenly an idea comes from nowhere.  That was the case here lol, well I was actually out running when it hit me.

[Nathan]

Can you show a pic of the hole the thermostat will go in? Is it so close to the tb that it might get heat-soaked?

[nobrakese36]

So how much is this gonnna run, im essentially ready to buy!!!

[bmwman91]

The breakdown is looking to be:
~$250 for the converter to start (from me), and could go up in the future
$40-100 for the MAF
Maybe $40+ for the mounting hardware, I will be looking into working with 666 Fab for the attachment stuff.
$0-20 for the GM IAT sensor
---------------------
$330-$410 probably.

I know, not the cheapest, but who knows.  Once everything is ironed out things can change.  It is still somewhat up in the air as far as production stuff goes.  I will do my best to keep cost for you guys to a minimum.

[bmwman91]

Sorry, missed the sensor placement question.

There is a bung in the underside of the rubber boot about 1" / 2.5cm from the TB.  Heat soak should not be an issue as I noted from the MegaSquirt experience.  If it was mounted in the aluminum manifold...then you would likely have a problem.

As long as you use the open-cage sensor, you should be fine if you are concerned about anything.  Response time is not really crucial in this application anyway...the sensor is more to ensure consitstent running than to do much to performance.  Once air begins flowing in any amount that would be indicitave of large throttle openings, the thing will be at the resistance it needs to be for proper WOT operation.

BTW
I got all the maps worked out.  Basically, if you are at WOT anywhere between -13F to 113F (-25C to 45C), the enrichments will kick in with no more than a 2.3% shift in RPM correction.  Outside this range, error increases by 2.3% for every +/-9F (+/-5C).  Lol, I don't know about you, but I'd say this takes care of basically everyone.

Who here lives at extreme altitude?  If you are above like 5000ft, the corrections in the 2500-3000RPM range will not be as effective, but everything will otherwise be fine.  No, no barometric correction on this lol!  The little sensors can be like $40 alone!

Sorry this is taking so long.  I just want to have ALL bases covered before I sell anything.  A robust product means less headaches for everyone.

[m3someday]

Hi BMWman

hope its not too late, see the pics of my successful DIY conversion below -
U requested for it a week back.  I'm not sure if the OEM connectors for this is easily available but it seems to be the standard 4 pin round BMW plugs that you can find in various other applications on the harness.

What i did was just get female bullet connectors, solder it to the harness, and directly plug it to the MAF to the corresponding pin. I then just slip the original rubber boot over the whole connection.

I just lifted this MAF from my mechanics parts bin. Its Siemens and the opening measure 2 3/4 inches.....anyone can confirm what MAF this belongs to?

[bmwman91]

Hmmm, the element in that one is even more open!  The design has no backflow protection at all like the Bosch one I am using.  Maybe the E36 M42's dual-intake system was designed to help with exactly this or something.  Lol, hrmmmm.....maybe the E30 M42 is the hardest motor I could have picked for this.  Guess I will have to call up my sister and convince her to let me make her car a guinnea pig!

Thanks for the pictures!

[tim_s]

The MAF above looks like an M52 one. hotwire MAFs shouldn't require much air density correction, because they respond to density changes at same air flowrate unlike the AFM. Having said that I use IAT based density correction as it gives me more consistent results, and yes, heat soak is an issue for me with the IAT and the sensor is just on the entry of my (fibreglass) intake plenum, so a long way from any alloy engine-attached bits. as far as IATs go, the later BMW sensors (M44 among other models) are calibrated the same as the IAT within the M42 AFM.

[tim_s]

oh and i have the part nos for the 4 pin MAF connectors and plastic housing etc for an OEM install if anyone needs them.
ta dah

[bmwman91]

How much do the connector bodies cost you?  Those things seem to get pretty pricey!

[nobrakese36]

What maf do we need if we chose to buy are own,thanks

[bmwman91]

Funny you asked, I was just looking around at OEM connectors and stuff.  Apparently, this MAF is pretty new, and a little pricier than I had initially thought.  The VW part number is:
06A 906 461L
and can be bought from (EDIT: SEE MY NEXT POST) for $132.  This is the only unit the conversion works with at the moment.  There are other similar MAFs out there that are cheaper, but I have not been able to get one in good condition to calibrate from.

VW PN 06A 906 461A is like $70 from the same site, although I do not have one, nor have I mapped one out.  I wish I had used that one simply because I know cost is a big thing for some people, but hindsight is 20/20.  So, do NOT use the 461A part...only the 461L part.  For now, the cost breakdown is kinda ugly (worst case):

Converter $250
MAF $135
Filter $40
Mounting Hardware (maybe) $50
GM IAT Sensor $20
------------------------
$495 in the end

Now, say you just decide to make your own velocity stack from some 2.75OD acrylic tubing or thin-wall metal pipe, and rig up some sort of brace yourself.  That knocks the mounting hardware cost down to like $10.  So, $455 total.

I do not even know how much cone filters are these days since I have been reusing a K&N one for like 6 years.  Maybe get away for $30.  $445 there.

Score yourself the GM IAT sensor from a wrecker...-$20....total $425.

Now, this is a big IF, but say it works with the OEM airbox with these corrections (I have not tried it there yet).  You will just need like 4" of 2.75" OD tubing and a little adapter found on all M10 E30's and many M20's at wreckers...no filter -$40, and say the same $10 for hardware.  Total, $385.

Again, the only problem with the airbox was that you ran lean at WOT between 2500 & 3000RPM.  With my maping corrections, this is probably not as much an issue anymore.  I will test this out soon.

Stuff sure adds up doesn't it.  I cannot blame Split Second for charging $1000 for a conversion kit.  Stuff is hard to keep inexpensive when it is something relatively complex like this.  What are peoples' thoughts on cost (though I cannot really do much about it)?

[nobrakese36]

Qusetion do you have any pics of the set up on your car, also what VW is it off? thanks

[nobrakese36]

Also you converter comes with the connector to directly plug into the maf right?

[bmwman91]

There were a number of models it came form I believe.

Here is the PROPER link to the MAF (with a list f models at the bottom):
http://www.worldimpex.com/parts/genuine-part-air-mass-meter-maf-rebuilt_268509.html

If someone can dig up this exact sensor for less $, it helps everyone out a lot.