Dual Fire Capacitor Discharge Ignition Page 1
Dual Fire CDI Instruction Manual VERSION 1.0 Warning Please ensure all power supplies are disconnected before commencing work. This product produces high voltages. Careless use of this product can cause harmful and fatal injury to humans. DO NOT handle the red/white or red/yellow wires if the unit is connected to power. Incorrect set-up of this product can also lead to engine and product damage. Any damage caused due to incorrect set-up will not be regarded as repairable under warranty. Any unused wires must be insulated to prevent them from short-circuiting. The power supply to this CDI must be fused with a fuse rated not more than 20 amp. Failure to follow all the warnings and instructions in this manual may lead to product and engine damage and will also void your warranty. Page 2
LIMITED WARRANTY EMS Computers Pty Ltd warrants the Dual Fire Capacitor Discharge system to be free from defects in material or workmanship for a period of 90 days from the date of purchase. Proof of purchase must be provided indicating that the product is within the warranty period in order to receive warranty service. Removing the serial number affixed to the product will void any warranty. If the Dual Fire Capacitor Discharge system is found to be defective within the rules mentioned above it will be replaced or repaired at no extra charge this constitutes the sole liability of EMS Computers. To the extent permitted by law, the foregoing is exclusive and in lieu of all other warranties or representations, either expressed or implied, including any implied warranty of merchantability or fitness. In no event shall EMS Computers, be liable for special or consequential damages. Page 3
CONTENTS Installation 5 Connecting to Power 5 Mounting 5 Ignition Leads and Sparkplugs 5 How to wire the input channels 6 How to wire the output channels 6 How to fire 2 channels together 7 How to wire the output channels for a rotary 7 How to discharge 2 capacitors into one coil 7 Overheat protection 7 Tacho output (brown/blue wire) 7 Operation modes 8 Rotary Mode (brown/yellow wire) 8 Trigger Edge (brown/white wire) 8 Power Select (brown/pink wire) 8 Mode Select (brown wire) 8 Specifications 9 Power Specifications Table 9 EMS Computers Dual Fire Pin Description 10 Drawings 11 Socket view 11 4 cylinder example 12 6 cylinder example 13 8 cylinder example 14 Rotary 3 coil example 15 Rotary 4 coil example 16 Page 4
Installation Connecting to Power The Dual Fire CDI has 2 red power wires and 2 black ground wires. These wires are joined together internally and should also be joined together at termination. The reason for using dual wires is to ensure maximum current flow. However, the amount of current draw is proportional to the number of cylinders and maximum RPM. Therefore, it may not be necessary to use dual wires if you have a 4 cylinder and not running the CDI in drag racing mode. As a safety feature the Dual Fire CDI does not keep power onto the positive side of the coils if the engine is not running. The system will charge the capacitors on initial power-up. If the engine is not started immediately the capacitors are discharged again. Once the system detects a trigger signal on any input channel it will immediately charge the capacitors and fire the next output channel in sequence. Mounting Do not mount the unit where it will be exposed to water or excessive moisture. Select a location away from excessive heat and in a location that does not obstruct air flow around the CDI. Use soft rubber mounts if the CDI will be subjected to strong vibration or the vehicle is has stiff suspension. Ignition Leads and Sparkplugs Do not use metal wire ignition leads because these will cause electrical interference that may effect the operation of the CDI or other electronic devices in the vehicle. Do not use carbon suppressed ignition leads because the carbon core is NOT capable of conducting the high energy levels of the CDI. Try to use ignition leads with a spiral wound inductively suppressed metal core. Not all brands of carbon resistor spark plugs are able to stand the high-energy output of a CDI system. NGK Q series and Champion Z series sparkplugs are specifically made for high-energy applications. IGNITION COILS AND THE CDI SYSTEM MAY BE DAMAGED INTERNALLY IF FIRED WITHOUT A HIGH VOLTAGE RETURN PATH. YOU MUST ENSURE THAT THE SPARKPLUGS ARE GROUNDED BEFORE FIRING. Page 5
How to wire the input channels The EMS Dual Fire CDI is essentially 2 CDI systems in one. The odd numbered channels use one discharge capacitor and the even numbered channels use another. In order to get the maximum benefit from the EMS Dual fire system you must wire the input and output channels in an odd-even sequence. To achieve this, connect the first cylinder to fire to channel 1, the second cylinder to fire to channel 2, the third to fire to channel 3 and so on. EG: If the firing order is 1,5,3,6,2,4 then connect the ECU ignition outputs to the CDI input channels according to the table below. Cylinder Firing CDI Input Channel Wire Colour Order from ECU 1 1 Pink 5 2 Orange 3 3 Grey 6 4 Yellow 2 5 White 4 6 Blue How to wire the output channels This also applies to the CDI output channels. The CDI channel outputs must be connected to the negative side of each coil. The positive side of the coils share two common voltage output banks, one for odd channels and one for even channels. The red/white wires must be connected to the positive side of the coils for all odd numbered channel outputs and the red/yellow wires must be connected to the positive side of the coils for each even numbered channel outputs. The red/white wires are connected together internally and the red/yellow wires are also connected together internally. EG: If the CDI input channels are connected as per the example above then connect the CDI output channels according to the table below. Cylinder Number CDI Output Channel CDI Output for Positive side of coil. for negative side of coil. 1 1 Pink/Black Red/White 5 2 Orange/Black Red/Yellow 3 3 Grey/Black Red/White 6 4 Yellow/Black Red/Yellow 2 5 White/Black Red/White 4 6 Blue/Black Red/Yellow Page 6
How to fire 2 channels together When you need to fire 2 channels at once then it is important to fire an odd and even channel together. In this way the CDI will discharge one capacitor for each coil being fired ensuring maximum energy to each coil. How to wire the output channels for a rotary A rotary engine fires a leading sparkplug and a trailing sparkplug very close together, its almost like firing 2 channels together. The leading coils of a rotary engine must be connected to an odd numbered channel and the trailing coils to an even numbered channel. This ensures that the leading plug uses one capacitor bank and the trailing plug uses the other. It is also important to use the odd numbered channels for the leading sparkplug because of the way the capacitors are charged in rotary mode. How to discharge 2 capacitors into one coil The EMS Dual Fire CDI system uses 2 charge capacitors, one for the odd numbered outputs and one for the even numbered outputs. Bridging one of the red/white wires with one of the red/yellow wires will cause the system to discharge both capacitors into one coil. This will give a longer lasting, hotter spark but at a reduced voltage. Overheat protection CDI systems provide high levels of electrical energy to the sparkplug coils. This means that high levels of current are drawn by the system, and like all high current devices, they can get hot. Although the Dual Fire CDI systems are able to deliver high energy levels for long periods of time, they can still overheat. If the system becomes too hot it will reduce the power output to a level where the system will start to cool down. Once a safer temperature is reached the system will resume full power again. Tacho output (brown/blue wire) This wire provides a 13.8 volt square wave output compatible with most tachos. Page 7
Operation modes The Dual Fire CDI system can be programmed to operate in different modes by either connecting the relevant wire to ground or leaving it unconnected. Rotary Mode (brown/yellow wire) Leaving this wire unconnected will put the CDI into piston engine mode. Connecting it to ground will put the CDI into rotary engine mode. Rotary engines have a leading and trailing sparkplug for each rotor. These can be fired simultaneously or the trailing just after the leading plug. For this reason you must connect the trailing plugs to an even numbered channel and the leading to an odd numbered channel. The system must also charge the discharge capacitors in a different manner to piston engines. Trigger Edge (brown/white wire) Leaving this wire unconnected will cause the CDI to fire each output on a falling input signal. Connecting it to ground will cause the CDI to fire each output channel on a rising input signal. All CDI systems have a delay time between the input channel signal and the output channel signal. This is mainly caused by the noise filtering circuit for each input. The Dual Fire CDI has a 28 microsecond delay for rising edge triggering and a 68 microsecond delay for falling edge trigger inputs. Most high-end after market ECUs such as EMS Motorsport ECUs have an ignition delay compensation adjustment that can be set to cancel this delay. IT IS VERY IMPORTANT TO SET THE TRIGGER EDGE ON THE CDI SYSTEM TO MATCH THE ECU SETTING. FAILING TO DO THIS MAY DAMAGE THE ENGINE. Power Select (brown/pink wire) Leaving this wire unconnected will cause the CDI to operate in low power mode. Connecting it to ground will cause the CDI to switch to high power. By connecting this wire to the auxiliary output of an ECU you can program it to switch the CDI between high and low power automatically in real time as needed. IE: Switch to high power mode when the engine is under heavy load. The power specifications table shows the power output for different mode and power settings Mode Select (brown wire) Leaving this wire unconnected will cause the CDI to operate in circuit racing mode. Connecting it to ground will cause the CDI it to operate in drag racing mode. In drag racing mode the CDI will deliver up to 570 volts to the coil. This can only be sustained continuously for about 3 minutes at 714 hertz before the CDI starts to cut back power to prevent over heating. This gives plenty of time to finish the race. In circuit racing where the engine is running at high RPM for extended periods of time this wire must be left unconnected. In this configuration the CDI is able do deliver up to 470 volts for very long periods of time at 714 hertz before its temperature becomes too high. Page 8
Specifications Maximum operating frequency: 714 hertz. Delay on rising trigger edge: 28 microseconds. Delay on falling trigger edge: 68 microseconds. Power Specifications Table Separated Banks Bridged Banks Circuit Mode Voltage Current Mili Joules Voltage Current Mili Joules Low Power 370 5.1 68 280 5.8 78 High Power 470 8.7 110 370 10.6 136 Drag Mode Low Power 470 8.7 110 370 10.6 136 High Power 570 11.3 162 400 15.6 160 The following output power and voltages are achieved with the battery voltage held at 13.8 Volts Page 9
EMS Computers Dual Fire Pin Description 1 Ground Black Ground 2 Ground Black Ground 3 Input 8 (8 Channel only) Violet Trigger signal 4 Input 6 (6 & 8 Channel only) Blue Trigger signal 5 Input 4 Yellow Trigger signal 6 Input 2 Orange Trigger signal 7 Input 7 (8 Channel only) Green Trigger signal 8 Input 5 (6 & 8 Channel only) White Trigger signal 9 Input 3 Grey Trigger signal 10 Input 1 Pink Trigger signal 11 12 V Power Red Ignition 12 Volts 12 12 V Power Red Ignition 12 Volts 13 Coil Output 1 Pink/Black Neg. Coil 14 15 16 Rotary Mode Brown/Yellow Ground this wire for Rotary mode 17 Trigg Edge Select (Rise/Fall) Brown/White Ground this wire for rising trigger. edge. 18 Power Select (High/Low) Brown/Pink Ground this wire for high power. Can be connected to ECU Aux output 19 Tacho Output Brown/Blue Square wave output 20 21 Mode Select (Drag/Circuit) Brown Ground this wire for drag mode 22 23 24 Output 8 (8 Channel only) Violet/Black Neg. Coil 25 Output 3 Grey/Black Neg. Coil 26 Output 5 (6 & 8 Channel only) White/Black Neg. Coil 27 Output 7 (8 Channel only) Green/Black Neg. Coil 28 Coil + for odd outputs Red/White Pos. coil for channels 1,3,5,7 29 Coil + for odd outputs Red/White Pos. coil for channels 1,3,5,7 30 31 32 Coil + for even outputs Red/Yellow Pos. coil for channels 2,4,6,8 33 Coil + for even outputs Red/Yellow Pos. coil for channels 2,4,6,8 34 Output 2 Orange/Black Neg. Coil 35 Output 4 Yellow/Black Neg. Coil 36 Output 6 (6 & 8 Channel only) Blue/Black Neg. Coil Page 10
Drawings Socket view Socket is viewed from the back. Page 11
4 cylinder example Page 12
6 cylinder example Page 13
8 cylinder example Page 14
Rotary 3 coil example Page 15
Rotary 4 coil example Page 16