Motronic 1.3 conversion for M30B28

Post your E12 technical questions and comments here. Please, no off-topic posts.

Moderators: Mike W., Pierre

Post Reply
User avatar
Joe Boston
Posts: 82
Joined: Sun Nov 27, 2016 12:11 pm
Location: Winchester, MA

Motronic 1.3 conversion for M30B28

Post by Joe Boston » Mon May 21, 2018 5:17 pm

has anyone install M30B35 wire harness with Motronic 1.3 with 179 ECU on M30B28 engine ?
Does anyone know if the 179 Ecu is compatible? or it this ECU specifically for 3.5 engine with high horsepower?
or would a megasquirt work best with M30B28 engine...
any insight is appreciated.
1980 E12 Ascatgrau 5 speed
2001 E38 740 Black
2012 F12 650 IC black

User avatar
Mike W.
Posts: 2451
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Re: Motronic 1.3 conversion for M30B28

Post by Mike W. » Tue May 22, 2018 12:09 pm

I don't think I've heard of it, but it should work ok. A bit less than optimum since the timing curve is for a 9:1 CR engine, not 8.2:1, but since the head and valves are proportionately larger for the 2.8, it should be mitigated somewhat. BMW used the same ECU and AFM on both 2.8 and 3.3 engines in the E12 era so those parts don't have to be exactly matched to engine size. Again, because of the lower compression ratio you might not realize the full benefits, but at worst I would expect a nicer, cleaner, smoother running engine with no loss of performance. Then again, you could always run M1.3 for fueling and a conventional distributor for timing.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter

RDAvena
Posts: 6
Joined: Mon Feb 06, 2017 2:13 pm
Location: Falcon, CO

Re: Motronic 1.3 conversion for M30B28

Post by RDAvena » Wed May 30, 2018 12:55 pm

Joe, I am doing the same "upgrade" to my 528i. Well , more of an in between step while the B35 gets built.
Hopefully it will be running on Motronic 1.3 by the end of June.

Adding all of the Motronic 1.3 parts should get it running until the ecu adapts and levels out to what the O2 sensor is reading.
Also using new water temp and O2 sensors should help eliminate some of the tuning issues.

Post Reply