325is EFI Installation

It’s been awhile since a lengthy post.  We have been busy this year completing and supporting various installs for the start of the season!

Dave’s 1987 BMW 325is project car.  


Dave’s car has had various configurations over the years.  A number of powertrains, and more.  Dave is a personal friend of mine, and last year we had some deep conversations about what his goals were for the car.  He wanted to install an advanced powertrain (BMW S54 engine from E46 M3), but also wanted to have enhanced motorsport functions on top of basic abilities to map the engine as well.  We decided to use an Emtron ECU system based on his needs.  

I can say that this car probably has one of the most “completed” road car calibration with a motorsport ECU system that I have ever heard of.  

Not only did we use every single component of the original engine (VANOS, electric throttle, idle speed valve, sensors, etc), but we even upgraded into high performance wide range o2 sensors the Emtron can natively control.  This electronics package overall truly modernizes this powertrain significantly.  

Here is a list of the calibration functions/strategies being employed on this build. Each section has used nearly all of the Emtron comprehensive flexibilities.  

Speed density fuel modeling

Closed loop wide range lambda sensors (one per 3 cylinders) with comprehensive trimming limits, lockouts, STFT/LTFT functions and more.

Closed loop idle speed valve control

Closed loop idle ignition control

Full drive by wire control with perfect function.  Throttle tracks target within 0.2% deadband regardless of varying mechanical geometry.  Full use of 3D tables for PID including feed forward.    

Full VANOS control with perfect closed loop function.  VVT targets faster than factory ECU as well as with more accuracy.  Original method of solenoid control is used as well (no regulation in deadband)  

Advanced air management using the idle speed valve as an “adder” at part throttle/tip in (same as factory).  The S54 uses an idle air distribution pipe that can support significant amount of engine load without opening the throttles.  When the DBW is not needed (at rest), the system has its PID function switched off to avoid over-regulation.  It is only used when needed.  The change over between the idle air management to the individual throttles is seamless, and fully configurable.  

Closed loop windowed knock detection with individual cylinder feedback using short term and long term gain functions

Transient ignition function

Overrunning fuel cut

Closed loop map blending (using Z-axis) based on a number of engine parameters (such as camshaft position)

Cold start function with warm up strategy

Integrated within the original wiring to ensure all gauges and warning lights (including check engine light) remain functional  

All sensors configured for error detection, with pre-programmed limp modes for major sensors, as well as active substitute value tables

Rear axle speed input

Gear detection

Launch control with comprehensive arming/disarming function

Gear dependent rev limiter

EFI relay control

Cooling fan control

Fuel pump control

Engine protection features

Comprehensive ECU data logging set

The result is a powertrain that has totally open live mapping, responds like a purpose built race engine (when needed), starts cold, runs clean, gets good fuel economy, and more!  The true definition of the lack of compromise when using a proper electronics solution!  

While this car is overkill regarding how in depth the calibration actually is (that point can be argued), it is a good example of how flexibility is important for any application.  This is exactly where the Emtron ECU system excels, and truly is the benchmark!  


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