How to choose the right ECU

Choosing the right ECU the first time is important to save time and money. 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 you more. There are 2 group choices to be made. Firstly which product range to choose and secondly which hardware class to choose for that product. Work through each point and narrow down your final choice.

Product Choice.

You need to consider your budget. Spitronics have the economy Pluto and Neptune range and the high quality Mercury range. Mercury being more expensive due to protected drivers, epoxy filled enclosure, more inputs and outputs and lastly external firing modules for coils with no intelligence.

• If you have people installing the unit that do not have lots of experience, Mercury is definitely the choice. It does not damage easily if short circuits are made. If installed properly, the economy range performs just as well as the Mercury range.
• 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 Mercury unit. It is epoxy-filled for vibration and moisture. Pluto can be epoxy-filled by yourselves after tuning should you require to do so.
• If it is a complex engine with lots of drivers and sensors the economy range may not be adequate and you need the Mercury anyway. Browse through the product comparison chart to see if the product will be the right one.
• The Economy range is repairable with some of the damage because it is not sealed.
• Coils also need to be considered. If you go for Mercury, coils with built-in drivers are connected directly. Coils without built-in drivers require the Mercury Coil Driver. See how many coils you have to buy the right combination of the Coil Driver. If you decide on the Pluto which has built-in coil drivers, it can connect to coils without built-in drivers directly. If you have coils with built-in drivers, then you need to wire in the 220 Ohm pull-up resistors and switch the firmware to external drivers. On the Pluto this setup is critical to have right at start-up or you may damage coils or drivers permanently.

Hardware Class Choice

• If your engine has more than 1 coil or a wasted spark coil pack, you will require an Advance ECU.
• If not your engine should house a distributor with rotor to distribute the spark. Mostly older type engines.
• 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.
• 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.
• Make sure that there is firmware for your application for the specific ECU. Some firmware requires the abilities of Mercury and is not available on the economy range products.
• Should you plan to do upgrades in the future buy the Advance ECU. You may also consider the programmer to change the firmware in the future.
• 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.
• 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.

Frequently Asked Questions

1. Is this unit a replacement for my car’s standard computer? No the Spitronics products are unique with their own connecters and operation. Some of the signals can be interfaced with the standard units to maintain other functions like instruments etc.

2. Which product will suit my application? It is easy to determine by the How to Choose and Comparison Chart topic further up this page. Read through all the points and narrow down which unit is suitable for your application.

3. What do I get with the kit? Once you made a selection please look at the Kit Packing Lists to see what is included in the kit and what else you need to buy separate. All kits come with harnesses to connect onto existing engine plugs. It does not include the engine connecters as there are too many variations. You simply solder the harness onto your existing connecters. We do stock some of the connecters but will only quote them on enquiry. Then the ECU kits come with a 2.5 Bar Map sensor which may be changed on request to a different type.

4. What do I need to buy extra? Any sensors not included in the kit like Air & Water temperature sensor, Oxygen sensor etc. that is not on the engine or has to be replaced due to failure or service date expire. The USB communications cable is sold separately because you only need one as a tuning tool. It is a must have component for the setup and tuning of the products. The Programmer is optional to change the firmware or install upgrades on the products afterwards.

5. Is the unit Plug & Play No it is more like Wire & Play. Meaning that there is a certain amount of installation time soldering and wiring to be done before the unit can be switched on. Then you may need to tune it to your engines parameters due to minor variation differences between engines.

6. Can I install and tune this unit successfully? These products were developed for the DIY market. But you do need a fair bit of knowledge and automotive skills to complete the project. Most auto electrical people should be able to assist if you have difficulties. If you study the manual properly you should be able the get your engine reasonably drivable with fair consumption and performance.

7. Does the unit need to be Dyno-Tuned after install? Some tuners found a way to tune it on the road quite successfully especially if there are no Dyno’s available. If you do have a facility and a recommended tuner it is advisable to have it tuned properly. Some units that are engine-specific may come with a tuned MAP on it for that engine. Then minor tuning is required and not necessary for a Dyno Tune.

8. Is the unit pre tuned? No but we do put a start-up MAP on the unit. These units are universal for different engines and it cannot cater for all variations in sensor and driver setup like injector sizes, fuel pressure etc. in some units that are engine-specific we will load a tuned MAP on it for that engine. It should start and be drivable around 90%. But some fine setup will make it more efficient.

9. Can this unit work for diesel engines? No Spitronics are busy developing a Diesel version.

10. Can this unit work for direct injectors? No but it is under development with the Diesel development which will be finished in the near future.

11. Can this unit work for Throttle by Wire systems? No but it is under development which will be finished in the near future.

12. Is this a piggy back system? No this is a standalone computer and does not require any other electronic units apart from its own units and the sensors on the engine.

13. Can this unit control my VVTI cams? It can control cams in open loop at this stage. Loop control is under development which will be finished in the near future.

14. Does this unit do Knock sensing? No knock sensing may be developed in the near future.

15. Does this unit self-tune? No the units do have loop control with the oxygen sensor and idle valve, but all tuning is done in open loop and these systems will fine tune in real time to optimise fuel mixtures.

16. Can this unit be used for racing fuels? Yes it does have two selection MAP’s to tune the engine for different fuels. These maps can be selected with a switch at start-up.

17. Can these units interface to my vehicle’ ECU via the CAN BUS No, these devices do not have CAN BUS capability