Choosing the right ECU the first time is important to save time and confidence. Please read this part with an open mind to help you choose wisely. Sometimes the cheapest option is not the best one and it may end up costing u more. There are two group choices to be made. Firstly, which product to choose and secondly which hardware class to choose for that product. Work through each point and narrow down your final choice.

Product Choice.

1. You need to consider your budget. Spitronics has the economy Orion and the high quality Mercury2. Mercury2 is more expensive due to protected drivers, epoxy filled enclosure, more inputs and outputs and external firing modules for coils with no intelligence. Some applications are only available in Mercury due to the complexity of the number of sensors and drive items. Orion also has a bootloader and can be reprogrammed with firmware without the need of a programmer.

2. If you have people installing the unit that does not have lots of experience, Mercury2 is definitely the choice. It does not damage easily if short circuits are made. If installed properly, Orion performs just as well as the Mercury2.

3. If you are abroad or far from Spitronics’ home base, it is also best to go for the Mercury2 option. Courier and time lost could be far more expensive than the money saved with the low cost products.

4. If you require the unit to be installed under harsh conditions like an off-road vehicle with lots of vibration and dampness it is best to go for the Mercury2 unit. It is epoxy-filled for vibration and moisture. Orion can be epoxy-filled by yourselves after tuning and setting the jumpers inside should you require to do so.

5. If it is a complex engine with lots of drivers and sensors the economy range may not be adequate and you need the Mercury2 anyway. Browse through the product comparison chart to see if the product will be the right one.

6. The Orion unit, depending on the type of damage, are repairable as these units are not sealed. We do have a one year reduced exchange rate guarantee should any of the ECU’s or TCU’s be damaged. See the pricelist for more info or contact our dealers.

7. Coils also need to be considered. If you go for Mercury2, coils with built-in drivers are connected directly. Coils without built-in drivers require the Mercury2 Coil Driver. See how many coils you have and buy the right combination of the Coil Driver. If you decide on Orion which has built-in coil drivers, it can connect to coils with or without built-in drivers directly. Not that the connections for the different types of coils is on different wires in the harness.

Hardware Class Choice

1. If your engine has more than 1 coil or a wasted spark coil pack, you will require an Advance or Ultimate ECU. If not your engine should house a distributor with rotor to distribute the spark. Mostly older type engines.

2. If it has a distributor and more than 4 cylinders you need the Intermediate ECU for correct fuel distribution with Split-Sequential or Full-Sequential delivery. A 3 cylinder will also require the Intermediate. If you are really on a tight budget you may use a Standard system and share the injectors on the 2 drivers. Note that there is a different way to connect low and high impedance injectors. Note also that standard systems can only do trigger per event signals.

3. If your trigger in the distributor is one pulse per spark event, then you may use the Standard or Intermediate. If it has a crank trigger with TDC slot or complex distributor signal with Home pulse you will require the Intermediate ECU.

4. Make sure that there is firmware for your application for the specific ECU. Some firmware requires the abilities of Mercury2 and is not available on Orion.

5. Should you plan to do upgrades in the future buy the Advance or Ultimate ECU. You may also consider the programmer to change the firmware in the future for Mercury2.

6. Note that higher class ECU’s will operate with lower class firmware for the same product. So if you buy an Advance ECU, you may start off with Standard or Intermediate firmware.

7. These hardware classes could be changed over the internet in the future following an upgrade payment. So you may buy a Standard ECU and upgrade it later to an Advance ECU. You may also consider the programmer to change the firmware in the future for Mercury2.