Project E46 M3: Part 6 – AEM Infinity Plug and Play EMS


Pictured here are the two wideband 02 sensors and harness extensions to reach the 02 sensor bungs on the headers.  Taking advantage of the AEM Infinity's internal dual wideband controller will clean the tune to a factory-like smoothness.

The AEM-supplied manifold air pressure (MAP) now takes the place of the mass air sensor (aka HFM in the BMW community for “hot film mass”).  This means we can replace the stock HFM with a less restrictive straight tube, or simply leave it unplugged, which we did for now.

In the earlier years of MAP tuning, it was difficult to get a stand-alone EMS-controlled car to run truly as smooth as stock in all conditions.  But with volumetric efficiency tuning, a processing speed of 400 MIPS (that’s millions of instructions per second), and drive-by-wire tuning, the system runs buttery smooth. 


Pictured here is the AEM Infinity EMS going into the stock ECU location.  Upon receiving the AEM EMS and the plug-and-play harness, it was hard to imagine how all of it would fit in the stock ECU location.  The instructions, however, call for removing and cutting the plastic ECU “skeleton” (that yellow-ish plastic you see in the picture above) that secures it to the car.  It’s a rather simple procedure that can be done with a saw or Dremel, and it doesn’t have to be perfect.

When all is said and done, the Infinity EMS sits vertically in the stock location, and the plug-and-play harness rests on top.

AEM did say in their instructions it would be a tight fit to reinstall the cover, and they weren’t kidding.  In fact, I could only use 3 of the 4 screws that secure the cover (but it’s not like it’s going anywhere).  The engine bay will still look factory though.

To leave the AEM Infinity EMS ready to accept sensors for any possible boosted applications in the future, we enlisted the help of Modified by KC to build us a separate harness.  More on that in the next few pages, along with our latest tuned dyno graph, CAN BUS features and launch video!

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