535i AFM installed using SMT6

[mspiegle]

before i got the SMT, i wanted to do the 535i AFM swap for fun. The AFM took forever to arrive, and i had the SMT6 long before the 535i AFM arrived...

anywho, i was gonna proceed like normal and buy another 325i afm to swap circuit boards... but wait a sec - i have an SMT6, why do i need to swap boards?

so i plugged in the 535i afm, fired up my car... and it started! but stalled quicky. I was a little fustrated that i couldn't keep the thing on long enough to see what voltages it was putting out. I went away from the project for a bit, then had a bright idea.

I noticed the stock 325i afm puts out about 1.33 volts at idle. So, i took the afm cover off, started my car, and noted where the afm's pickup-arm was. I took the 535i afm, plugged it in, and moved the arm to the same spot. It read the same voltage.

I was quite dumbfounded why it shouldnt work if they both put out the same voltage. So, with the 535i afm hooked up, i started my car and noticed that the arm wasn't moving to the same spot. I manually held the arm on the 535i afm to the spot where the 325i afm would be. Car idled perfectly.

I then noted the differences in voltages and setup a basic map on the SMT6 to compensate. I started the car again, and voila! perfect start and almost-perfect idle.

I drove around a bit and noted what the O2 sensor was telling me. After making a bunch of adjustments, the car runs within 13.5 - 14.5 MOST of the time. At the higher rpms, it leans out slightly.... I think i need to put my larger 19# injectors in there to add some more fuel for all the new air that's comming in =)

oh, and also, i have a big ass K&N attatched to that AFM... the sound is unreal. I've never heard a 325i before with a K&N. It just makes a loud growl from 4K to redline. Beautiful!!

Once i get a digicam again, i'll prolly take some pics. I need to get my piping straighted out... i'm currently using alot of duct tape. Also, my bracket to hold the 535i afm on is made out of duct tape =)

I will be constructing something made out of steel soon enough...

Aside from the kick ass sound, i think it felt slightly stronger. Not a whole lot, but it was noticeable. I'm gonna go race my friend with an accord and see if anything has changed...

[theo325]

Good job dude! I had to swap my 325i board to make mine work. What exactly is the SMT-6?

[mspiegle]

http://www.r3vlimited.com/phpBB2/viewtopic.php?t=514

[gstuning]

:)

I told you man with the smt6 in anything goes

[Chapel]

neat.
Ill do a search to get the info on this, rather than wasting bandwidth or reposting.

[AdamF 88iS]

Gunni,

How difficult is it to convert to MAF with SMT6? For the money it's almost hard to justify not getting an SMT and if I can go to MAF easily with it then it'll probably be my next mod.

[mspiegle]

i think its mainly getting a variable tps on there, and making a good map so the ecu can work w/ the maf.

its my next intake project.

[mspiegle]

http://www.nauticaltech.com/~mike/index.php?object_id=174

theres my finished product for now. I'm gonna drive around on it for a bit and once i'm satisfied, i will make a steel bracket for the AFM, then use it 'till i get a maf.

[gstuning]

It´s just comes down to tuning the signals from the maf for the ecu,
you can run anything in there if you get the signals right,

Getting a varible TPS for the smt6 is also a great thing, make tuning way easier,
a varible will not work with the stock ecu,

[mspiegle]

well, my take on the whole 535i mod is that you may not need to swap electronics or use an SMT6 to make it work...

If you take the cover off both AFMs, you will notice inside that there is a little arm that touches a contact plate. This arm is actuated by the door that allows air in.

If you manually move both arms so that they are half way through the plate, both AFMs read the same voltage. Unless my 535i afm had the 325 electronics before i got it (which i'm kinda doubting) then I don't see the need to swap boards if they put out the same voltage.

When you start the motor, the 535i AFM's afm doesn't goto the same spot as the 325i arm. But, if you start the car with the 535i, then run over to the engine bay and manually push the arm to where it should be, the car starts to idle fine.

With some adjusting of the spring and the start-position of the arm, my 535i afm seems to work the same way the 325i does. I will further confirm that this morning, but I think that's where i'm at.

[JRowe]

[mspiegle]

[JRowe]

[mspiegle]