50 State Legal S55 ECU Calibration per EO # D-691-4.


The F8x M3/M4 vehicles are just too tempting when it comes to upgrades.  While they have great performance right off the show room floor, it is just too hard to leave them untouched.  That's what happened when a member of the Weistec team picked up an F82 M4.  Immediately, the ECU was removed and we set to work on modifying and testing.  After months of testing on our own vehicle as well as a few other test vehicles, the Weistec S55 ECU Upgrade was ready


The Weistec S55 tune provides solid gains through out the entire powerband, with peak to peak gains of 40HP* and mid range gains of as much as 120HP* and 160lb-ft of torque!  This is on an otherwise 100% stock vehicle, including the air filters!


In addition to the performance gains, there are a couple options available for race vehicles.  First is the "Burble".  The M4 GTS comes from the factory with this in a mild form.  You can choose "Off" "Mild" or "Aggressive" for the "Burble".  Many seem to prefer aggressive, but we gladly will let you choose based on your preference.


The other race vehicle option would be Catalyst Heating.  On race vehicles, many times the catalysts are removed.  In those cases, there is no need for the catalyst heating which would just be making excessive noise on a cold start of the race vehicle.  If you have a race vehicle with the catalysts removed, Catalyst Heating can be disabled.


Cypher | Powered by Weistec

The Cypher is an optional upgrade when purchasing a Weistec tune for your Fxx series BMW. Simply navigate our website to the tune you wish to purchase. On the tune’s product page there will be a drop-down menu giving the option to add Cypher to your tune order. From there, the order is processed, and a Cypher tool will be shipped to you

  • No need to send in your ECU / DME computer
  • Swap tunes file or return the stock within minutes.


Weistec S55 ECU Power 

What does all this mean to you?  More power, sharper throttle response, and consistent performance with out sacrificing refinement. 

*Power gains vary based on model, modifications, fuel, and running conditions.


ECU Calibration Process: How do I get my ECU Calibrated?

Key Features:

  • Improved Throttle Response

  • Optimized Fuel, Spark, and Boost

  • 40 Wheel Horse Power Peak to Peak Gains

  • Up to 120HP gains in the mid range

  • M4 GTS "Burble" Mild and Aggressive Options (for Race Vehicles only)

  • Disabled Cold Start (for Race Vehicles only)

  • Disabled Speed Limiter

Weistec Engineering S55 ECU Calibration