I am sorry for writting this in English, but my German is very poor.
I have a 1986 535i with the "green" 8:0 compression 185HP M30 engine.
The standard Motronic Steuergerät for this car is code 0 261 200 059.
I removed the "kat" and O2 sensor from the car, and I run open loop now.
I intend to install the 0 261 200 061 Steuergerät, specific to the higher compression 218HP M30 engine, instead of the original 0 261 200 059, in the idea of getting some more HP out of the engine.
What's your opinion? Would this work with nice results? Any problems I should have in mind?
I would highly appreciate any reply. You can also write in German - I can manage reading it :)

Hello Robert,

It is no Problem to remove the catalytic converter,but to change the Motronic is not good for your Engine,because there are other general technical data for the lower compression engine.
You can kill the engine!
The better way is you you drill an inside thread for your O2 Sensor into your first waste gas pot,and connect the O2 Sensor normaly.
The driving power is a little bit higher than with catalytic converter,and your fuel consumption is lower!
And your engine got a longer live!

Greetings
Ralf

I have a 1986 535i with the "green" 8:0 compression 185HP M30 engine.
The standard Motronic Steuergerät for this car is code 0 261 200 059.

I removed the "kat" and O2 sensor from the car, and I run open loop now.
I intend to install the 0 261 200 061 Steuergerät, specific to the higher compression 218HP M30 engine, instead of the original 0 261 200 059, in the idea of getting some more HP out of the engine.

What's your opinion? Would this work with nice results? Any problems I should have in mind?

I would highly appreciate any reply. You can also write in German - I can manage reading it :)

My car