BMW E21 323i M20B23 swap to M20B25

[jsimon20]

Hi everyone,

I have a BMW E21 323i and I want to put a M20B25 from a BMW E30 325i.

I would like to know if someone in this forum already did this swap or if you know exactly what things I have to change in order to do this. I would use everything stock except the ECUthat I already bought a Megasquirt.

I am using a 5th gear dogleg gearbox.


Thanks.

[arshad76]

Hi Simon,

This conversion has been done many, many times. Did you try searching for previous topics? You should find everything that you need. I'd say it's a worthwhile conversion and I had it done to my E21 too. Good luck

[BertjeConti]

"Megasquirt" i like that !

[jsimon20]

"Megasquirt" i like that !

I am trying to get the engine maps in order to start testing, do you know were I can get them?

I will be posting new information here, this might take some weeks.

[BertjeConti]

I have maps for my M20B20. Engine runs perfect with these maps.
I presume they will do for a start for your engine.

What ignition setup are you planning ?

[jsimon20]

I have maps for my M20B20. Engine runs perfect with these maps.
I presume they will do for a start for your engine.

What ignition setup are you planning ?

I am not decided yet. What do you recommend?

Ok, it would be great if you could send me those maps.

Thanks

[BertjeConti]

The easiest ignition setup is a wasted spark setup. You'll need a 6 cilinder coil pack for that. You won't need a cam shaft sensor for this setup and even then choose for a semi sequential injection setup.
I did it this way and i like it because it isn't complicated and much better than the standard motronic.

I''l pm you my ignition and ve tables.