Make your own MAF conversion for under $50, I did it

[hakentt]

After experimenting with different MAF conversions over the years, I came to conclusion that stock AFM is not restrictive at all and does a good job. Don't waste your time and money on any of the MAF conversion products for our E30 M20

[n3dsd]

an excellent conversion ...do you mind if I post this elsewhere as i think it should be shared..
I have the Miller maf and did not have to cut any wires ..just spade connected it to the male plug but I think they now provide a proper female connector.
Rather than run the power from the fse box I scotch locked mine to the live coming into the box where the relays are(under the word "done" in your pic). it has worked for 2 years now with no probs

[hakentt]

an excellent conversion ...do you mind if I post this elsewhere as i think it should be shared..
I have the Miller maf and did not have to cut any wires ..just spade connected it to the male plug but I think they now provide a proper female connector.
Rather than run the power from the fse box I scotch locked mine to the live coming into the box where the relays are(under the word "done" in your pic). it has worked for 2 years now with no probs

Yes feel free to share this information, thats the reason I posted it.

[DmcL]

kick azz.. must keep an eye out for a hayundai MAF.

how did the car run before tweaking the map? i havent the facilities to tune the car and im running a performance chip atm. have no idea what the specs on the chip are other than it raises the redline to 7k rpms. im also running a 173 FWIW.

[Shadow86325e]

sounds like it revs a lot smoother too.

[hakentt]

You don't need to have 173 ecu. You can have 380, 524, 525 or even 179, they will all work in E30 year 88 to 91, they will all take chip from 173 and will work fine.

sounds like it revs a lot smoother too.

It does feel like that, but I got automatic so it feels lazy anyway, I can't notice much difference.

how did the car run before tweaking the map?

started right up and ran rich, you need a software you can't run the car without it even tho it runs.

[Three Dee]

So, how would this work on an '84 325e?

[hakentt]

So, how would this work on an '84 325e?

You got motronic 1.0 with ecu number 0 261 200 027
That is even easier to tune for MAF, but I don't have a 84-87 car to test it on,

[Three Dee]

I'll have to remember that for future reference. RIght now our focus is just on getting the car started. After that, who knows what will happen?

[Shadow86325e]

It does feel like that, but I got automatic so it feels lazy anyway, I can't notice much difference.

Manual conversion time!

Also, how about a 1986 BMW 325e?

I also forget which ECU I have, I got one from the junk yard out of another '86 and the car runs better.

[kishg]

nice.. it's always nice when someone thinks about a problem, does the necessary research and provides a solution instead of the usual half-ass crap.

[creeves328]

Applause for the OP! Its been 15 years since I owned an e30, but back then I hated the dreaded flap-style air-meter. I had a very radical m20, and only resort (without going Motec) was the M30 larger flap meter. Good job OP!

[johnnyhammers]

You are a total goober for doing this...and I LOVE IT!!
thanks for being creative and innovative!
Good work!

[bmwman91]

Cool man! How much $ was all the ECU-emulation stuff?

[hakentt]

After driving the car for two days now with this maf conversion, I can say that I do feel better throttle response and smoother reving.
Emulation tool is $180 but you don't need it. It is only for tuning the car properly with new things then you just burn the file on the chip. I will be working on some more tunes like bigger injectors and other upgrades and I will post the tunes so anybody can try it. I offered to do this while back here and was threatened by moderation because they tought that there is no way that I am doing this for free. Vendors are promoting their products here making money on people but I can't even share my findings here for free? I don't understand it, forum is all about sharing information.

[e30Terp]

I'm curious to see how the software you mentioned will work with an e36 MAF. I have one for a 97 M3 and have been looking into the tuning issues. Where do you get the software?

[hakentt]

97 M3 maf is 4 pin it lacks features. that maf is not a good choice. I already said what kind of software I am using to tune 173 ecu in my original post.

[bmwman91]

If you are being hindered by air temperature sensors (or a lack thereof), I can help you. When I did my stand-alone MAF conversion, I took measurements & determined the thermistor's coefficients, and you can get ones with the right coefficients for like $0.22 on Digikey. Just stuff them in anywhere & hook them up...I have been running my car with one for like 20k miles. This gave me a LOT more freedom in choosing a MAF.

My DIY story is here:
http://bmw.e30tuner.com/articles_mafcon.php

[hakentt]

If you are being hindered by air temperature sensors (or a lack thereof), I can help you. When I did my stand-alone MAF conversion, I took measurements & determined the thermistor's coefficients, and you can get ones with the right coefficients for like $0.22 on Digikey. Just stuff them in anywhere & hook them up...I have been running my car with one for like 20k miles. This gave me a LOT more freedom in choosing a MAF.

My DIY story is here:
http://bmw.e30tuner.com/articles_mafcon.php

Interesting read there, the problem with your project is you used a sensor that is more compex to convert, then you built a controller that will convert the signal to ecu instead of tuning the ecu's software directly.
Using the sensor that I am using the conversion is simple. I was tuning by using wideband 02 sensor to nail the proper air fuel ratio over whole rpm range and I drove the car and tuned it by driving it, this is more effecting then trying to tune the components on the bench.
I am glad that you have proven with facts that there is no actual horsepower gain because stock afm is not that restrictive, once the momentum of the mass air passes and flap opens it does not restrict the flow it actualy glides over the mass air passing. I haven't seen a second party dyno tests other than what miller is claiming 20hp gain.

[bmwman91]

Interesting read there, the problem with your project is you used a sensor that is more compex to convert, then you built a controller that will convert the signal to ecu instead of tuning the ecu's software directly.
Using the sensor that I am using the conversion is simple. I was tuning by using wideband 02 sensor to nail the proper air fuel ratio over whole rpm range and I drove the car and tuned it by driving it, this is more effecting then trying to tune the components on the bench.
I am glad that you have proven with facts that there is no actual horsepower gain because stock afm is not that restrictive, once the momentum of the mass air passes and flap opens it does not restrict the flow it actualy glides over the mass air passing. I haven't seen a second party dyno tests other than what miller is claiming 20hp gain.

Yeah, the AFM "restriction" thing is the driving force behind people wanting a MAF. Basically, the small amount of force your finger needs to push the flap open is all the resistance the flap creates...which is none for all practical purposes. Now, MAF's do have other benefits as it sounds like you found, such as better response. I found that my idle improved as well.

We sort of took opposite routes to do this. I didn't want to mess with the ECU (well, I ran Megasquirt on my first car, but that was too much trouble for a largely stock motor). Being that I design electronic measurement systems / instrumentation for fun and here & there at work when it is needed, I figured that messing with the signal-side would be more fun. Initially, I had planned to sell MAF conversion kits. Sadly, if something does not make more HP, 95% of the consumer market loses interest immediately; you could sell something that makes the car fly, and it wouldn't sell if you couldn't claim improvements on a dyno.

I will not state this as fact as I have no personal experience with Miller, nor do I have an opinion about them (good or bad), but here's my guess about the 20hp claim. It is probably true, with a caveat. The 20hp is relative to stock ECU tuning with an AFM. They don't JUST sell a MAF converison, they sell a tuned chip. The gains are basically identical to those seen with a Conforti or MarkD chip, and the "Big-Six" AFM conversion (since the M20i's AFM is a little under-sized). They are not lying about anything, they are just marketing, which is what everyone in the automotive aftermarket has to do to stay in business.

[hakentt]

you could sell something that makes the car fly, and it wouldn't sell if you couldn't claim improvements on a dyno.

well said

[Alkasquawlik]

What exactly are the benefits of the MAF conversion?
Not trying to be a dick, I just have no clue.

[triggrhaapi]

The engine, in general, runs better. Also, it's an exercise in knowledge. It's like the uber nerd version of a custom engine rebuild. Electronics are always the tricky part of newer technology, and the people who understand how it works always end up king. This thread gets 100% thumbs up. Awesome read.

[n3dsd]

the experience here across the pond of Miller Mafs is that they do not produce massive horsepower gains but much better throttle response and excellent gains in torque but this is usually tied in with other mods such as BBTBs and 6 branch headers...for instance mine pulls all the way from 1k revs in 5th which makes for a very pleasant driving experience ,especialy in traffic.

[hakentt]

What exactly are the benefits of the MAF conversion?
Not trying to be a dick, I just have no clue.

If you got MAF you are cool. If you have stock AFM then you are not cool.


I did quick search in google, and found few articles, this one is from porsche parts vendor:

the quicker throttle response and revving happier characteristics encountered with newer engines then this is a must have upgrade for you.

Then found another page where they dynoed 1988 M3 with and without maf conversion, gain was ~10+ hp, and ~10+ torq, here is the link: http://grassrootsmotorsports.com/art...rs-older-cars/

All tho it is different engine than M20 you can see it on the dyno sheet how drastic the low rpm power improved, maybe this is why everybody say better throttle response