M/S5X Engine Guys, Weird Request in San Francisco Bay Area

[bmwman91]

This will probably sound pretty random, but here goes.

If anyone here in the South Bay Area (I am around San Jose) is running an M/S5X engine with the Motronic ECU (and I assume most are), I need to get some oscilloscope measurements of the ignition coil dwell time. I have the scope, and basically I would just need 5 minutes to clip the probe on to one of the coil wires (which means popping the plastic cover off), and then 15-30 minutes of driving around so I can get readings during warm-up and a couple of WOT pulls.

The particular coils that I want to get measurements with are these Bremi ones (the round-body style):

https://c1552172.ssl.cf0.rackcdn.com/232041_x800.jpg

Why? I am going to be making the move to stand-alone engine management in the near future, and I want to have a solid idea of the proper dwell time for these coils since they are what I am using in my COP conversion kit. I don't want to base things solely on measurements from my car since I am using the M42's Motronic with them, which was programmed for the M42's coils which are different than these. It runs fine, but I just want to see what the factory dwell time for these M/S5X coils was.

I'll pay for your gas and buy you lunch for the trouble. Let me know if you are free to do this at some point in the next couple of weeks! Thanks.

[2mAn]

If I get a few extra days off (between christmas and new years) and Im in San Jose, I will let you know

[kronus]

if only my m50 was behaving right :/

[bmwman91]

If I get a few extra days off (between christmas and new years) and Im in San Jose, I will let you know

Cool man, I will be around so drop me a line if you are in town!

[GunMetalGrey]

Please post your findings, I'm curious to see how they compare to what I'm running mine at.

[bmwman91]

if only my m50 was behaving right :/

What's up with your M50?

Please post your findings, I'm curious to see how they compare to what I'm running mine at.

Will do. Ideally, I would like to get measurements on a variety of BMW's so we can build up a database.


After a little looking around, it seems that the Bosch and Bremi coils are in fact fully interchangeable, so whatever I discover regarding dwell times, it will apply to both. There was some issue with Bremi coils in 2004 which resulted in a recall (and it explains why the coils I used for my COP conversion in ~2006 partially melted and died once, but not again after being replaced). Anyway, being interchangeable, that means that they have to work with the same dwell settings since the DME won't know which ones someone is using.

[kronus]

after exhausting all other possibilities, i'm thinking cracked head. pulling it this weekend.

[bmwman91]

after exhausting all other possibilities, i'm thinking cracked head. pulling it this weekend.

Shiiiiiiit. Is it as much of a common issue on the M50 as it is with the M42? From what I understand *knocks on wood* the M42 almost always cracks between the exhaust valves on cylinder 2 (and sometimes 3).

[kronus]

from talking to a shop owner, they pulled three m50 heads in one day and two of them had cracks. don't know where, but it sounds common.

[bmwman91]

Hey Simon, any plans to be in the Bay Area this week?

[2mAn]

I should be in San Jose from Christmas until early into the week, still have my fingers crossed I will be there with my car. We'll see

[bmwman91]

Cool, shoot me a text if you are around town. I should be mostly free next week.

If anyone else in the south bay wants to get some ignition measurements, let me know and I will see about scoping some signals. Maybe I can build up an "ultimate" E30 / E36 ignition dwell settings database for everyone.

[Jonnybravo]

I've got an m50 swapped E30 but don't have a passenger seat. If you want to take it for a spin to get your reading, we could probably work out a time.

[bmwman91]

What year/version M50 is it?

[Jonnybravo]

It's from a 93. Non vanos.
Pm me if you wanna meet up