Electronic Fuel Injection FAQ
- Should I use the stock ECU from my car? Generally, the GSL-SE ECU is not advisable for using in a turbocharged
application. The GSL-SE computer wasn't designed for boost, and as such,
it won't properly accommodate fuel delivery under boost. Although the
Cartech turbo kits were originally designed for use on a GSL-SE, newly
available computer options make the GSL-SE 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 II ECU for my project? The Turbo II ECU is readily available, and when coupled with the Turbo II engine and
Turbo II 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. A fuel cut defenser (FCD) can be purchased to
override the computers stock boost fuel cut parameter to allow higher boost
- 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.
a) Haltech E6K - a commonly used EFI computer for the rotary
b) Wolf 3D - popular in Australia, and growing in use in the
US in many rotary vehicles.
c) SDS (Simple Digital Systems) - A low cost alternative
d) Microtech - Simple system, low cost
e) Electromotive TEC-III - Higher end system
f) Megasquirt - a Do-It-Yourself "kit" that you must build
and test (fuel only). Works with any sensors, including Mazda or GM
g) Motec - a high end system commonly used in racing
- How should I choose a EFI computer? As mentioned in question 3, 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.
a) 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
b) What features of the computer accommodate the rotary
engine specifically? If the computer supports ignition (spark), it
should be able to accurately control both leading and trailing plugs.
c) What additional features of your TurboFB project
might require special functions from the ECU? Do you need to control 2,
4, 6 or 8 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?
d) 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 knowledgable 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
e) 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
f) 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?