I received some details from Hartge, which BTW informed me that TunerMotorsport is indeed the only Hartge dealer for US and Canada.
I will forward the details they agreed to share with the community:
The Hartge Engine Conversion is significantly different to other, often cheaper systems.
Our Hi-Tech system contains many "smart" technical features, and is the result of many months of design, testing and durability trials. The investment we have made during the development program has resulted in a full 3 year warranty on the hardware and software.
Technical features are as follows:
The Hartge ECU is an external additional control unit. It is internally sealed and cannot be detected by BMW service procedure interrogations. It is also not possible that BMW software updates can disturb the performance of the Hartge ECU. Unlike engine management "chipping" and "flash" upgrades, it never gets overwritten during service enhancements by BMW.
Example 35i (new engine N55 - 1 Turbo - TwinSroll)
The Hartge ECU is connected via a special wiring harness to the air flow meter, camshaft sensor, boost pressure sensor 1, boost pressure sensor 2, turbo valve, water temperature sensor, rail pressure sensor, and power supplies (all plug and play).
Additional power is generated by increasing the turbo boost pressure by a precisely calculated number.
This number depending on engine speed, calculated engine load and other parameters. The BMW ECU continues to monitor all other important engine parameters as standard.
In extreme temperature conditions, the Hartge ECU also monitors the exhaust gas temperature, and if this exceeds the safe limit, the Hartge ECU reduces power accordingly back to standard BMW power.
There is also overload protection, which prevents full power from being delivered for excessively long periods of time, for example when towing heavy loads, or driving for too long at V-max.
Finally, to protect the engine from stress, the Hartge ECU will only allow full engine performance to be achieved when the engine has reached operating temperature (more than 158 degrees Fahrenheit / 70 degrees Celsius)
All standard BMW engine protection and emissions systems remain in place and continue to function.
Our piggyback system comes with an illustrated installation manual.
Please contact our North American distributor Turner Motorsport www.turnermotorsport.com
for further information.1