functional MAF conversion !

[diegom6]

holly shitt, niether me....just I have to learn the program in the SMT6 to tune that thing...

[E30godz]

yes michael! i was searching for this post and i wanted to ressurect it...so im guessing you took the power wire to the AFM and used it to power the MAF you bought, then just checked the plugs until you found the analog voltage, then used the other AFM signal wire, and wired it to your MAF, correct? I may look into doing this...i could probably whore a ford MAF or something cheap too!..as anyone figured out how to get a TPS on the M20 yet? i know the SMT-6 uses the deflection off the AFM signal, but this isnt the best way i assume.

[mspiegle]

as far as the deflection goes, the MAF isn't much worse than the AFM... at least the particular one i'm using. I think the trick is to find a MAF that has a somewhat linear signal.

I heard of other people using a bosch (i think?) MAF from earlier e36s, and they had serious lean@idle + rich@WOT issues. I don't seem to have any of these problems and my SMT6 MAP is VERY simple...

I ordered a MAF connector from a guy a week ago, assuming he comes through, my engine bay should be much cleaner without my spagetti wiring.

My next step is to install a tempurature sensor in the intake stream so the ECU has that signal and turns off the 'check engine light'. Once everything is said and done... the SMT6 map is so simple i might be able to use it to design a low-cost circuit so people can do cheap (less than $200) MAF conversions.

[E30godz]

can you post a picture? I'm interested! I'll start on the hunt for an MAF with a linear signal, im sure SOMEONE makes one. Please go on with your plans for the "kit"...i bet it would piss split second off though, and rightly so...outrageous asking price for their crap!

right now my AFM deflection is set between 20% and 60% which encompasses off throttle, to it being floored. i have a jeep TPS sensor laying around and may try to rig it up to the throttle somehow..shouldnt be too bad.

[Digitalwave]

Michael, you can save your maps in SMT-6 right? You should save what you have and send it to the other guys trying this so they have a baseline.

[E30godz]

an excellent idea...i would think, to use this correctly, we would HAVE to adapt a real TPS sensor....normally the SMT-6 would use the TPS for throttle deflection....yet on the M20's with no REAL tps, it uses the analog AFM signal...the newer MAF'ed cars use real TPS sensors and thus has no need for the MAF as a reference point...its only used to control fuel...the signal it sends out will not be linear, as the amount of air flowing by is dependent on throttle position AND the rpm's..so for this to work flawlessly...we shal have to find an MAF from a car that uses a throttle switch style sensor, as opposed to a real TPS...anyone follow? i may be completely wrong. ; )

[reelizmpro]

A suggestion for Gunni or ???

The SMT6 unit is pretty impressive and it's price is a definate advantage over the rest. I wanted to suggest offering SMT6 kits with or without a MAF. SO many people will buy it/commit to it if it's a standardized MAF conversion kit ready to go. There are a lot of people out there who have no idea what the difference between AFM and MAF is, let alone be able to figure out how to implement a MAF using the SMT by themselves.

[Digitalwave]

Re: A suggestion for Gunni or ???

The SMT6 unit is pretty impressive and it's price is a definate advantage over the rest. I wanted to suggest offering SMT6 kits with or without a MAF. SO many people will buy it/commit to it if it's a standardized MAF conversion kit ready to go. There are a lot of people out there who have no idea what the difference between AFM and MAF is, let alone be able to figure out how to implement a MAF using the SMT by themselves.

If they are buying SMT-6, there is a good chance that they know what a MAF is.

[rwh11385]

:D Bimmerforums is a great place to get a good deal on MAFs. As soon as I grab one, I can link you guys to the remaining ones for sale. I wanna make sure I get the best deal for myself! 8)

[mspiegle]

The AFM works because when you open the throttle, your engine tries to suck in more air, that sucking effect moves the large AFM door and that movment is measured.

The MAF works on the same principle, except instead of a door moving, you just have a hot-wire that gets cooled down as air flows over it.

Once again, i DO NOT have a TPS running on my car. I just wanted to 'try it' and see if my car would even run, and to my suprise - it ran just as good as my car with a normal AFM. No doubt I will be putting a TPS on to get fully accurate maps, but it runs pretty decently without.

I keep forgetting pictures + writeups + bla bla bla. I'm trying to figure out how much work it would be to design a circuit that does the conversion for you. If it ends up being too much work, or costly, then the SMT6 is the best bet. It is a very handy device.

[mspiegle]

oh, and ebay is a decent place for MAFs. Just for reference, i am using a '98 328i MAF made by SEIMENS

[E30godz]

whats the difference between the siemens and bosch unit?

[E30godz]

yes i realize how the MAF works ; ) but did you understand what i was saying?

[mspiegle]

i know, but i was trying to illiustrate that the AFM amd MAF are much more similar than you might think. The AFM has to respond to throttle/rpm too - and because of that, I was able to use my MAF without a variable TPS.

I specifically said mine was a seimens unit because i belive that bosch units may have a different scale. That is harder to look at.

Honestly, the map I have is almsot a 1:1 conversion of the signal. I think I could have used 15s across the entire map and it would have worked fine, but its slightly different. I think it starts around 13, then moves up to 18 or so. No major compensation for the signal needed to be made.

[rwh11385]

Hey mspiegle, I just a deal on 21.5# injectors and 328 MAF!

I'll buy the SMT6 in a couple months, after I get my DELL laptop.

Anyway, what injectors are you planning on running, and do you think a adj. fuel pressure regulator will be neccesary? My gut intinct is saying yes most likely.

So I'm thinking of doing all this late spring/summer: Injectors, AFPR from bavauto or IE, MAF, SMT6..... :D 8)

In the meantime I think I'll get a JC chip. And I'll probably keep it in with the SMT6. I might appreciate the extra revs, and it will be much less of a pain to tune the timing. The A/F tuning will be very helpful to obtain all the potential from my cam and MAF tho! :twisted:

p.s. For two deals on MAFs: http://www.r3vlimited.com/phpBB2/viewtopic.php?t=1974