Vaf to maf conversion project.

[NicholasJackson]

Im taking my new inquired knowledge of circuitry from university and i'm attempting to convert the vaf system to maf system. The plan is to have a standalone kit to plug straight into the vaf wiring then plug the unit into the maf sensor no need for a obd2 ecu or standalone ecu.

Ive done a lot of reading and as i understand there is two types of maf sensors, one that users the temperature of a wire (hot wire sensor) to output a voltage and one that uses Kármán vortex which outputs a frequency, higher the rpm higher the frequency.

Both of these seem promising, although the frequency maf will be a little trickier.

If you have any information you feel necessary to help please share or even broken maf or vafs you have you would like to share.

[NicholasJackson]

Is anyone actually interested in this? Because i won't publish this is if no one cares?

[91_festy_Gl]

I think its a good idea but I wouldnt mess with a maf or vaf. I would just get a standalone and zero out either maf or vaf.

[NicholasJackson]

Fair enough.

[Motoxpress]

This is an interesting idea. On the Festiva the fuel pump is activated by the movement of the vaf door. I'm curious how this will work with a maf.

[NicholasJackson]

Well what im looking into creating is just a chip to give the same reading as a vaf would give but with a maf. When the vaf moves it moves the potentiometer which changes the resistance. On the 323 for example it goes from 20 ohms to 1000 ohms from wide open to shut. What i still need to test is whether it takes that resistance with the 12 volts and gives a respective voltage. The chip will convert the signal from the maf and give the same reading as a maf would, but with less air resistance as the vaf.

Ive done some research on idle frequencies with the maf of the mazda 323 and then the voltages the vaf gives and done some preliminary calculations and ive been pretty close something like 10hz off which is only .1 volts.

Looking promising.

[Grey Vw]

Far too complicated for my feeble mind to comprehend

[angrygocart]

I'm interested!

[NicholasJackson]

Just think BP engines with sexy intake tubes without an ugly box on the end. And the switch taking only 30 seconds!

[Rocketman]

IIRC the VAF uses a 2-9V signal (at least the B6T?) while most MAF's use a fairly standard 0-5V signal.

There was a guy in New Zealand on FordLaser who did the exact thing you're talking about, but he had to use a microprocessor to make it all work, there is basically no relation in signal between the VAF and most MAF's. He used a GM 3-wire sensor.

//Did a little looking around. Here's the unit he came up with: http://www.fordlaser.com/viewtopic.php?t=70944

Here's a topic showing some flowbench #'s and other various research http://www.fordlaser.com/viewtopic.php?t=34148&start=89

EDIT: here is yet another link with some really good info: http://www.fordlaser.com/viewtopic.php?t=44990

Good luck with your project!

[NicholasJackson]

That's exactly what im doing, thank you very much.

[Occhty]

This is interesting, and I'm not any kind of electronics guru. But is there any other benefit to this mod besides airflow/lean/rich? And if it's just about airflow/lean/rich, it seems to me it would be easier to just replace the vaf with a comparable, mechanical, variable resitor that could mount up the way the trottle positioning sensor does, then you could also tie another one ( mechanical, variable, resitor )/( old timers know this as a volume control knob ) mounted on the dash for lean/rich setting?

Am I missunderstanding the whole thing here? If I am can anyone explain it a little more detail?

[Rocketman]

Yes you're misunderstanding. The airflow into the engine is not linear with the throttle position. (especially in a boosted application) As far as I'm understanding, OP's objective is to replace the VAF with a MAF for the sole purpose of removing a the flapper-door, as opposed to a method of tuning, but I could be wrong there as OP hasn't been specific on that part.


Nick, have you looked into Megasquirt at all?

[blkfordsedan]

Just out of curiosity, how hard would it be to convert to MAF from an Aspire? I'm sure we've probably covered that before, but I don't remember.

[NicholasJackson]

Yeah i hate the idea of having the air flow restricted to measure it. Im exploring two possibilities just a simple signal converter or a signal converter that can be tuned, im still in the preliminary stages of research.

Rocketman, I have thought about megasquirt but the whole pupose of this project is to see whether i can create a standalone connector without the need for a aftermarket ecu.

Brian that's an aspect im exploring last, as i understand it the aspire maf is a hotwire maf. I want to look into the vertex maf first as ive done a lot of work in frequencies at uni this past year.

Nick.