quick MAF question

Post Fri Jan 27, 2006 10:12 pm

Why do some e36 ones have 6 connections rather than 4?
cheers
tim

Post Sat Jan 28, 2006 8:21 pm

anyone any ideas?

Post Sat Jan 28, 2006 8:23 pm

the bosch MAFs I've got to play with have 5 pins

Post Sat Jan 28, 2006 8:34 pm

jeez, more confusion

what're the 5 then? does it have an IAT on it?

Post Sat Jan 28, 2006 9:47 pm

There are quite a few different e36 MAF's.

The best one to use for a e30 M20 conversion is the Siemens HFM found on 328i's.

Post Sat Jan 28, 2006 10:33 pm

tim_s wrote:jeez, more confusion
what're the 5 then? does it have an IAT on it?

yes

Post Sat Jan 28, 2006 11:12 pm

how does the output compare to the e30 one? that an e36 one? think i'll prob just use my orig IAT tbh, at least then i know its gonna have the correct output.

Post Sat Jan 28, 2006 11:45 pm

I've not got that far yet. How are you proposing to swap them?

Post Sun Jan 29, 2006 12:02 am

just remove from old AFM and drill into new MAF. guys in the states do it this way.

Post Sun Jan 29, 2006 12:05 am

sorry I meant for the actual MAF.

Post Sun Jan 29, 2006 12:08 am

hoping to use a perfect power smt6 or 7. i have lots of other changes to do the fuelling etc due to the throttle bodies and capacity increase so need a piggyback really.

Post Sun Jan 29, 2006 12:26 am

cool sounds like you doing some heavy mods then

Post Sun Jan 29, 2006 10:39 am

2.1 m42 on tbs mate!

Post Sun Jan 29, 2006 11:08 am

Awesome dude. gonna be a monster!

Going off topic now but how far are you with it?

Post Sun Jan 29, 2006 11:27 am

lol, the throttle bodies are mated up to the head perfectly now, am struggling with plenum and trumpet design at the mo, but its too damn cold to take the car apart and do some more playing really. think i have an idea of how its going to work now though.
the 2.1 bottom end is at engine shop no2 (engine shop no1 was too expensive), being rebored next wk and all the other machining will follow in the next few wks.
have found an ok source for the piggyback, am hoping to sell on some bits to generate a bit of cash to help pay for it. next month or two should see some good progress. plan is to mate the tbs and remap etc first, then once its running well add the bottom end.

Post Sun Jan 29, 2006 11:39 am

sounds good. how you gonna go about the mapping?

Post Sun Jan 29, 2006 9:11 pm

got a mate who is quite good at mapping stuff to help me if needs be, otherwise just do a load of datalogging on the original setup, then take all voltages at different rpms/loads etc, then plug in maf, get idle voltage correct and work through until all is well. can data-log wideband lambda so all should be ok. also if i get the more advanced of the two piggybacks, it can automatically learn a new sensor if you plug the two into it together and leave them both in for a while so none of that would be necessary. unfortunately can't find a uk supplier for these atm and they cost more anyway.
how abouts yourself? would be interested to hear your plans

Post Sun Jan 29, 2006 10:41 pm

gunnirain@hotmail.com (MSN) supplies SMT I think. Also try SBD motorsport (google)

Don't know if you've seen, I'm just trying to make a MAF conversion kit, not full standalone or anything.

Is based on PIC microprocessor. coding in C.

Want to be able to store the a map between the two meters basically fool the ECU just like you'll be doing. Initially I'll be taking idle redline readings of the AFM and MAF. details of storing and taking initial readins have yet to be worked out...

Still in early stages but will be keeping the zone posted

Post Mon Jan 30, 2006 7:58 pm

that should be pretty cool. there's a chap in the states doing something very similar... let us know how you get on

Post Mon Jan 30, 2006 8:28 pm

Some useful info

Andy

Post Mon Jan 30, 2006 9:28 pm

cheers guys. yes Andy mate I remember that thread. Basically my project will be to create the unichip bit, but it will only interface the MAF. Will be an awful lot cheap and do almost as much good if I can ever get it to a marketable stage... long long way ahead but you gotta have dreams

Post Mon Jan 30, 2006 9:40 pm

Thought of it too, just got to sit down and work the elctronics out, shouldn't be too difficult, just been busy with the 24v converstion

Andy

Post Mon Jan 30, 2006 9:49 pm

cool. had you thought at all about how to do the electronics?

I know a lot of old school boys would do it purely in analog but that's too much for me.. I'm a 21st century digital boy.

Post Mon Jan 30, 2006 9:53 pm

Hi dude, started to think about the electronics in analog but digital would also be good

Both could be made to be ajustable, but I guess the digital would be more tuneable

Andy

Post Mon Jan 30, 2006 9:59 pm

I haven't the fainest idea of how to even begin to think about the possibility of doing it analog. haha. How would you go about it?

For me, the digital is so clear:

MAF -> ADC -> DSP - DAC - ECU

simple

Probably a technology overkill for the job but gives good flexability, tuneability etc.

Post Mon Jan 30, 2006 10:06 pm

dsp? dude?

The main task to overcome is to convert a liniar signal into a non liniar output (or visa-versa) can't remember which is which

ADC and DAC's are good fun

used them at school for a clock project

Andy

Post Mon Jan 30, 2006 10:17 pm

but how would you do such a thing in analog?

By DSP I just mean the code in the pic processor, to do things that I hope to be able to implement like a lean crusing system, to ease back on the AFR if air flow hasn't changed for x amount of time. Also additional accel enrichment, again by monitoring the air flow over a given time period.

I don't have to think about the different curves fortunately. as long as the input is 0 - 5v and the ecu wants a 0 - 5v then the curve could be anything.

I can't remember which is which either. Info is pretty hard to come on such things!