Electronic Fuel Injection FAQ

Should I use the stock ECU from my car?

Generally, the stock ECU is not advisable for using in a turbocharged application. The stock computer wasn't designed for boost, and as such, it won't properly accommodate fuel delivery under boost. Although the turbo kits were originally designed for use on a stock ECU, newly available computer options make the stock ECU a poor choice. There are a few of the newer piggyback computers which may be used successfully in controlling the injectors. Timing is still a consideration, however, and you should ensure you are able to retard spark timing under boost.

Should I use a Turbo ECU for my project?

The Turbo ECU is readily available, and when coupled with the Turbo engine and Turbo wiring harness, this option provides a cost effective EFI computer. If you don't require boost levels too much higher than stock (8 psi), this option works well. This would only be useful if you were doing a swap, simply because there is no Turbo ECU that'll fit a FIRE engine. On a 1242cc this may work but has not been tested.

What's the best aftermarket EFI system to use?

There are several systems available on the market now. In general, all systems provide the same basic functionality; the ability to control fuel delivery under varying conditions. Other features which differentiate the systems are programmability, ignition control, boost control, data logging, diagnostic display, fuel map point resolution, and support.

Haltech E6K - a commonly used EFI computer for the rotary vehicle.
Wolf 3D - popular in Australia, and growing in use in the US in many rotary vehicles.
SDS (Simple Digital Systems) - A low cost alternative
Microtech - Simple system, low cost
Electromotive TEC-III - Higher end system
MegaSquirt - a Do-It-Yourself "kit" that you must build and test (fuel only and fuel and ignition versions). Works with any sensors, including Mazda or GM sensors.
Motec - a high end system commonly used in racing applications

How should I choose a EFI computer?

As mentioned in the question above, the number of factors that differentiate one system from another goes quite far beyond cost. Although more thorough reviews of each of the major available systems will be added, the following checklist of questions should help you do your research, and narrow down the list of candidates. The best system for you is the one that meets your needs the best. Many people have said that installation and tuning support is one of the more critical decision factors.

How much money do you want to spend? From the low end (MegaSquirt) to the high end (Motec or TEC-III) the price range varies from $100 to $5,000 for the equipment alone. Expect to pay standard labor rates if you have a speed shop or Carb/EFI shop install the computer for you.
What features of the computer accommodate your needs specifically? If the computer supports ignition (spark), it should be able to accurately control timing as well.
What additional features of your Turbo Fire project might require special functions from the ECU? Do you need to control 2, 4, 6, 8 or 12 injectors? Is integrated boost control a requirement? Do you need to accommodate A/C idle control via the BAC (bypass air control valve)? How well suited is the ECU to climate in your area for cold starting? How is acceleration enrichment handled?
How do you accomplish programming of the fuel and ignition maps? If you must use a laptop, can you reasonably drive the vehicle and program, or do you need a second knowledgeable person to assist you? If the ECU has a handheld programmer, can it perform all of the functionality required while driving? What type of display is available while in car? What kind of data logging is available for on-demand or post-run tuning?
What support is available? Will you be able to call someone for help on the weekend? Do you have e-mail support? Web support? How far away is the closest technician who can provide over the phone or hands on support? How much does the support cost? What type of installation support is available versus post-installation tuning support?
ECUs can offer upgrades for software from time to time. What is the upgrade plan for your ECU? How much do you have to pay for upgrades to the ECU firmware? How about the datalogging or real time viewing software? Does it run in Windows? Does it work with newer versions of Windows?

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