Stock ECU MAF replacement project

[prj]

How do you stand on this? I would like to test stuff with my old Motronic.....still have it in case I use it on the SWB project.

Really off topic, probably best to talk about it elsewhere, but I am not interested in publishing everything yet.

BTW what would be approx the price for this conversion board?

I am aiming for a price of 200-250 EUR for a brand new genuine Bosch MAF in the correct housing with the board attached to it.

The board will be pretty cheap to make, it's the engineering involved that's difficult and the MAF sensor from Bosch + housing will be also about 100 EUR.
I am not an electrical engineer, so even simple things like reverse current protection are difficult for me, because there are many options and I don't know which to pick

For example reverse protection on the 0-5V signal from the MAF, would probably be a diode with a fuse or a MOSFET.
Reverse protection on the +12V feed could be just a series diode, etc...

Basically I have the following inputs:
+12V - connected to the car
GND - ECU ground
0-5V - Signal from HFM5

And the following outputs:
+5V reference for HFM5
0-6V - Conditioned signal to ECU

Considering this thing will be possibly installed by people who can mess things up (sorry ), I need to make sure that if things accidentally are connected the wrong way around, the board does not melt.

The ones that are connected by people, will be +12V, GND, ECU signal. So at the very minimum, there needs to be reverse voltage protection on +12V/GND, short circuit and reverse voltage protection on the ECU signal.

[Matas]

I think this tutorial will help you:
http://www.youtube.com/watch?feature...v=IrB-FPcv1Dc#!

[Billman]

Really off topic, probably best to talk about it elsewhere, but I am not interested in publishing everything yet.

You're right. I just saw it.

[prj]

I think this tutorial will help you:
http://www.youtube.com/watch?feature...v=IrB-FPcv1Dc#!

This is very basic, I already know all that.
I just don't have a lot of experience with design, so I don't know what kind of chips exist for certain tasks etc.

I will probably just make something, and then take my circuit to an electrical engineer for a 2nd opinion. See what they say.

[Matas]

Well, my hobby is electronics, maybe I can help.

[prj]

Well, my hobby is electronics, maybe I can help.

So, which voltage regulator would you use?
I am thinking of LM309

[Matas]

At my place your voltage regulator is quite pricey and for 5V it should get at least 7.4V. LM7805 has same characteristics and is very cheap. LM2937 is even better with wide working temps and low voltage dropout

[prj]

...

[prj]

Actually you are right.
LM309 costs something like 30 EUR.
Ignore my previous posts I searched for the opamp for some reason... getting sleepy.

I guess LM2937 it is then with a bunch of caps around it, that takes care of the reverse polarity protection as well.

[hcman]

I will probably just make something, and then take my circuit to an electrical engineer for a 2nd opinion. See what they say.

Hi, i can help you with schematics, with protections etc., feel free to contact me

[prj]

Thanks for the offer...
I have a few things left to do, then I might take advantage of it

[EspenW]

This sounds VERY promising

[quattro84]

Indeed, i am watching these topics very closely.
I don't have the time nor the skills to reverse engineer the code but i would even be willing to pay for a workable guide with software setup based on the stock motronic.

[prj]

And we have progress.

I have written the firmware and have the rev1 board laid out for the converter.
The firmware is working on the evaluation board - I have mappable output based on input.

Next step is to print a few boards and order the components.

Now, the last remaining problem was the connector.
I believe the solution will be:

1) Cut off the old connector
2) On the board I will have these:
http://www.farnell.com/datasheets/652883.pdf (unless someone has a better idea.
You just put the wire in the position and push the cap on, done. No soldering, crimping, tools.
3) On the other end of the board the HFM5 connector will already be hanging out, so you just plug that into the new MAF.

So, going forward:
1) Cars <450hp will use the RS4 element in an Alfa housing, this should fit like stock, and with the converter the electrical output will actually match the RS2 MAF.
2) Cars >450hp will use the Pro-M 3" Pro-Tube blow through solution, which can read enough air for 1200 horsepower. They will also use the same converter, but it will be specially calibrated and the ECU will be specially calibrated as well.

Currently writing the software for calibration...
Goodbye wires.

[Error404]