Author Topic: Megasquirt as Piggy Back (Read 6683 times)

Deyan · « **on:** February 12, 2009, 07:31:52 PM »

Hi Everyone,
I am not new in this forum, but I've lost my old account pass, but thats not so big problem. I had this threats about small version of Megasquirt used within the Motronic box and use the OEM Harness. This was 2 years ago, after that I put M50B25 in my E30, but I had car accident and now I have E36 316, but It will get M42B18

... this was like a small introduction and now the real thoughts.
Here I will write only about the ECU - Part of my Project. The last time I used MS mounted in Motronic and used the OEM Harness. This was pretty PlugnPlay, the only thing I used were EDIS Coils from Ford. There were some problems with the idle, but nothing so much to worry. The big problem for me was the spark. My spark table was not enought good and I wasn't happy with that. So this time I think going to use the MS like piggy back. I will control only the FUEL and the Motronic will control the SPARK. I will speak with my MS-Friend

and we will discuss how it would be the best to do that. I wrote this thread, because I would like to know if someone did this already??? Later when I have more infos, like fuel tables and feedbacks I will write here.

Best Regards, D.S.

doitover · « **Reply #1 on:** February 13, 2009, 11:44:45 AM »

There is a lot of good information in this thread.

http://www.e30tech.com/forum/showthread.php?t=50206

Deyan · « **Reply #2 on:** February 13, 2009, 05:29:40 PM »

The Plug n Play MS in Motronic is no problem. I've already used one

This time my idea is to use it as Piggy Back. I've spoken with a friend of mine and he told me, that the biggest problem is from where to get the rpm signal. If we take it from the VR-Sensor, the signal can be too weak for MS and Motronic. Good point is to take it before the coils, but it is not like M20 and he thinks, that the MS will get twice as much rpm as it is ... for example if the engine revs 5000 rpms, the MS gets 10000 rpms. And this sux. I will think about that, but if there is no good solution, I can go with the Motronic Plug N Play MegaSquirt. I have a threat about it -> nick: Alibi (or Alibitu)

odbod · « **Reply #3 on:** February 15, 2009, 03:46:59 PM »

Can you use the rpm signal from the feed to the dash board, or is this too weak?

Deyan · « **Reply #4 on:** February 16, 2009, 10:44:03 AM »

Quote from: odbod;66575

Can you use the rpm signal from the feed to the dash board, or is this too weak?

That was one of my ideas, but he told me it won't work. Here are some of the opportunities:

1. VR-Signal in 2 Exits (one for ECU, one for MS). Signal can be too weak.
2. VR-Signal to ECU. From ECU to Coils (take Signal to MS). Problem can be instead 5000 rpm, MS read 10000 rpm.
3. VR-Signal to MS and from MS the same signal as an Output to ECU. (I wait for an Answer)
4. EDIS 36-1 with Pulsereader and EDIS 4 Reader ECU to MS (made for EDIS). VR-Sensor to ECU. The car will be with 60-2 and 36-1 wheels. It is complicated and I am not sure how it will be done. But if this works, than we have the OEM Signal and an EDIS Signal for MS and we can always go on full Ignition and Fuel with EDIS afterthat.

I know some of you will say, why all this crap and problems, but the Idea is: The car is everyday driveable (we all know, that it is very hard to achiev that with MS) and when we do some modifications, where more fuel is needed to manage that in few minutes. Of course there is always the opportunity that someone modifies the Motronic Chip for the Ignition.

Deyan · « **Reply #5 on:** February 19, 2009, 11:23:36 AM »

This is how it could be done: 4 diods for the 4 coils, which adds the signal and for the MS it will looks like one coil working 4 times .. like a distributor. It doesn't sound complicated and I think I will go for it. After all I can always go for a Spark and Fuel with MS.