GEMS

Gems has been designing and building competition engine management systems since 1985. Because of an ongoing policy of developing products in response to the needs of its customers, and in many cases in close collaboration with its customers, the range of products available are now highly flexible and covers all engine management requirements.

Gems manufacture a number of ECUs including PNP applications for Evo and Impreza. The table below shows the features of each ECU

ECU Name EM36 EM40 X25 Mitsubishi EVO Plug & Play Subaru Impreza Plug & Play Impreza R Series Plug & Play Notes
Cylinders
Max Sequential 12 12 12 4 4 4
Max Semi-Sequential 12 12 24 n/a n/a n/a
Max Coil Per Plug 6 6 8 4 4 4
Max Wasted Spark 12 12 16 n/a n/a n/a
Rotary 3 3 4 n/a n/a n/a
EM36 EM40 X25 Evo Plug and Play Impreza Plug and Play Impreza R Series Plug and Play
Features
Uneven Firing Angles Yes Yes Yes Yes Yes Yes
Boost Control Yes Yes Yes Yes Yes Yes
Idle Control Yes Yes Yes Yes Yes Yes
2 Stage Idle Control Yes Yes Yes Yes Yes Yes
Cam Control Yes Yes Yes Yes Yes Yes
Variable Valve Timing Yes (2 Channel) Yes (2 Channel) Yes (4 Channel) Yes (2 Channel) Yes (2 Channel) Yes (2 Channel)
Closed Loop Fuelling Yes Yes Yes Yes Yes Yes
Auto Mapping Yes Yes Yes Yes Yes Yes
Max RPM 12000 15000 25000 9000 9000 9000 Can vary depending on timing pattern
Twin Spark Engines Yes Yes Yes No No No
Twin Injector Engines Yes Yes Yes No No No
Traction Control Yes Yes Yes Yes Yes Yes
Launch Control No No Yes Yes Yes No
Anti-Lag Yes* Yes* Yes Yes Yes Yes* *Track/Road ALS – Reduced agressiveness compared other ECUs
Anti-Lag Modes 1 1 2 2 2 1
Alternate Fuel mode Yes Yes Yes Yes Yes Yes
Full throttle gear change Yes Yes Yes Yes Yes Yes
Voltage Compensation Yes Yes Yes Yes Yes Yes
Drive By Wire Throttle Control Optional Extra Yes Yes Yes No No
Active Throttle Control Yes Yes Yes Yes No No
Knock Control Yes Yes Yes 2 Yes Yes Yes
Gear Calculation Yes Yes Yes Yes Yes Yes
Gear based fuel Modifiers Yes Yes Yes Yes Yes Yes
Gear based spark Modifiers Yes Yes Yes Yes Yes Yes
Gear based boost Modifiers Yes Yes Yes Yes Yes Yes
Gear based Rev Limits Yes Yes Yes Yes Yes Yes
Sensor failure detection Yes Yes Yes Yes Yes Yes
Fuel Trims Per Cylinder Yes Yes Yes Yes Yes Yes
Ignition Trims Per Cylinder Yes Yes Yes Yes Yes Yes
Switchable Boost Yes Yes Yes Yes Yes Yes
EGT Fuel Correction No No Yes No No No
EGT Boost Correction No No Yes Yes Yes Yes
Temperature Dependant Cuts/Retards Yes Yes Yes Yes Yes Yes
Fuel Pump Control Yes Yes Yes Yes Yes Yes
Intercooler Spray Control Yes Yes Yes Yes
Independent upstream injector control Yes Yes Yes No No No
Lambda Feedback Control Yes Yes Yes Yes Yes Yes
Lambda Heater Control Yes Yes Yes Yes Yes Yes
Nitrous Control No No Yes No No No
Water Injection Control No No Yes No No No
Radiator Fan Control Yes Yes Yes Yes Yes Yes
Vehicle Speed Calculation Yes Yes Yes Yes Yes Yes
User Configurable Tables 4 4 1 1 1 1
Fuel tank guage Yes Yes No No No No
Upgradeable firmware Yes Yes Yes Yes Yes Yes
EM36 EM40 X25 Evo Plug and Play Impreza Plug and Play Impreza R Series Plug and Play
Inputs
Throttle Yes Yes Yes Yes Yes Yes
Water Temp Yes Yes Yes Yes Yes Yes
Air Temp Yes Yes Yes Yes Yes Yes
MAP Yes Yes Yes Yes Yes Yes
MAF Yes Yes Yes Yes Yes
Baro Internal Internal No Internal Internal Internal
EGT No No Yes (4) Yes Yes Yes
Lambda 2 2 Yes Yes 2 Yes 2 Yes
Wideband Lambda No No Yes 2 Yes No No
Oil Pressure No No Yes Yes (Switch) No No
Fuel Pressure No No Yes No No No
Oil Temp No No Yes No No No
Battery Voltage Yes 2 Yes 2 Yes Yes Yes Yes
Wheel Speeds Yes 1 Yes 1 Yes Yes Yes Yes
Crank Yes Yes Yes Yes Yes Yes
Cam Yes 2 Yes 2 Yes 4 Yes 4 Yes (2/3*) Yes (2/3*) *2002 models
Launch Switch n/a n/a Yes Yes Yes No
Anti-Lag Switch Yes Yes Yes Yes Yes Yes
Alternate Fuel Switch Yes Yes Yes Yes Yes Yes Can be used for Nitrous control
Analogue Inputs which can be used as Digital Inputs 16 16 16
Max Spare Inputs 9 11 22 3 2 3 Depends on usage of other inputs and outputs
EM36 EM40 X25 Evo Plug and Play Impreza Plug and Play Impreza R Series Plug and Play
Outputs
Ignition 6 x 8amp 6 x 8 amp 8 x 15 amp 4 4 4 EM40 outputs either coil or ignition or general
Injection 12 x 3amp 10 x 3amp 12 or 8 x pk hold 4 4 4
Bridge Optional Extra 1 6 1 3 1
Total 20 20 25 12 18 10
Total High side 2 2 4 0 1 1
Fuel Pump Yes Yes Yes Yes Yes Yes
Air Con Yes Yes Yes Yes Yes Yes
Tacho Yes Yes Yes Yes Yes Yes
Shift Light Yes Yes Yes Yes Yes Yes
EM36 EM40 X25 Evo Plug and Play Impreza Plug and Play Impreza R Series Plug and Play
Data-logging
Memory 512KB 512KB 1MB 512KB (8MB in Evo X) 512KB 512KB
Max Logging Speed 250Hz 250Hz 250Hz 250Hz 250Hz 250Hz
Telemetry
CAN Yes Yes Yes (2) Yes (2 on Evo X) Yes Yes
Serial Yes Yes Yes Yes Yes Yes
PC Communication
Serial RS232C Yes Yes Yes Yes Yes Yes
USB 1.1 No No Yes Evo X Only No No
Comms Connector 9 Pin D-Type Not separated Autosport 3 Pin Binder * 3 Pin Binder 3 Pin Binder *Evo X also has Autosport Comms Connector which is used for the USB Comms
Metrics
Size mm 200 x 105 x 45 130 x 90 x 30 160 x 145 x 35 OE OE OE
Weight grams 645 300 580
Connector
Type AMP 36 Autosport Autosport OE OE OE
Number 1 3 3 OE OE OE