There are numerous books that focus on high-performance mechanical mods, but
here’s a first – a book dedicated to modification of car electronics
Performance Electronics for
Cars gives high-performance enthusiasts an understanding of how their car’s
electronic systems operate and details enhancement of these systems using newly
released off-the-shelf products developed by the publisher, Silicon Chip.
The content and the products are nothing short of groundbreaking.
In the first chapters, the book leads readers through the basics of EFI and
engine management systems – the inputs, outputs and ECU decision making. It also
explains the difference between open-loop and closed-loop operating and various
other principles that are required to establish an understanding of
modifications explained later. It’s all to the point and easy for a beginner to
The modification side of things begins with an explanation of when you might
need to make changes and the best way to go about them. Interceptor, chip or
programmable management? The book helps steer you in the appropriate direction.
Tools of the Trade
Modifying your car’s electronics requires a completely different set of tools
to those you already have in your toolbox – the most important piece of
equipment is a good multimeter.
Performance Electronics for
Cars dedicates two chapters to selecting a suitable multimeter, how to use it
for different applications and how it should be used in conjunction with wiring
diagrams and other materials. It might seem all too obvious, but it's precious
This is augmented with a chapter on how to assemble electronic kits. If
you’ve never held a soldering iron before, we strongly suggest reading about
parts overlay diagrams, polarity, ICs and more before taking the plunge with any
of the kits detailed in the book. There’s also a useful sequence of illustrations
showing what your soldered connections should (and shouldn’t!) look like.
The first 40 pages of this 160 page book are dedicated to understanding car
electronic systems, approaches to modification and the equipment necessary to
tackle them. Now we get into the Do-It-Yourself projects...
There are 3 instrument-type kits covered in the book – the Smart Mixture
Meter, Injector Duty Cycle Meter and a High Temperature Digital Thermometer. The
operating principles, construction, calibration and use of each kit are covered
in 8 pages on each project.
The Smart Mixture Meter gives you a 10 LED readout of air-fuel mixtures, as
derived from your car’s oxygen sensor. While this is a concept familiar to
regular AutoSpeed readers, the Smart Mixture Meter adds a very useful function
to warn of a potentially destructive engine lean-out – there’s an alarm that
sounds at a predetermined lean level and at high engine load. This is a great
feature for when all of your attention is focussed on driving.
Next, the Injector Duty Cycle Meter is a handy device for checking your fuel
system’s scope for increased power. In a typical situation where you’ve modified
your car’s intake and exhaust, the Injector Duty Cycle Meter can be used to see
if the existing injectors are operating up to around 100 percent duty cycle (ie
they can’t flow any more fuel at that fuel pressure).
Interestingly, the Injector Duty Cycle Meter also doubles as a duty cycle
based switching device. It allows you to – for example - activate a water
injection system at a predetermined injector duty cycle. Note, however, this is
a difficult kit to assemble with up to three separate PC boards required.
The last instrument-type kit is the High Temperature Digital Thermometer.
This temperature meter can be used with your choice of a LCD or LED display and
is intended for use with K-Type thermocouples. It is rated to over 1200 degrees
Celsius (depending on the probe), which makes it suitable for measuring exhaust
gas temp, brake temp and all automotive fluid temps. It also has the ability to
switch on/off devices on the basis of measured temperature – the switch on/off
points can be set separately and the onboard switching relay can handle loads up
to 5A. This kit is built on a single, highly-populated PC board – it’s fiddly
Each of the chapters on these instrument-style kits contains high quality
photographs of the completed circuit board, a parts layout diagram and parts
list. The construction of the kit, installation and calibration is explained in
relatively simple language. The expanded “How it Works” section is more
complicated and is focussed at experienced electronics gurus – but there’s no
need to fully understand it to get the kit up and running.
The following five chapters cover kits that have a switching output based on
different inputs. The Versatile Auto Timer, Simple Voltage Switch, Temperature
Switch, Frequency Switch and Delta Throttle Timer are ideal approaches to
switching water sprays, cooling fans, changing transmission mode, a ‘power-on’
delay for power windows and more.
The Simple Voltage Switch, Temperature Switch and Frequency Switch also
feature adjustable hysteresis (allowing their switch-on and switch-off values to
be set separately). They are relatively easy to build and come with a relay
rated at 5 amps.
Probably the most ingenious of the bunch is the Delta Throttle Timer – it
doesn’t look merely at a given input voltage, but at the rate of voltage change.
This means you can wire the Delta Throttle Timer to your car’s throttle position
sensor and whenever you quickly hit the throttle, it triggers an output relay.
This relay can be configured to activate an intercooler water spray, switch to
the transmission’s ‘Power’ mode or whatever you like. But, remember, it’s not
the absolute voltage that’s important – it’s the rate of voltage change.
And now we arrive at the chapters that can potentially change the face of
The first cab off the rank is the Digital Pulse Adjuster (DPA). The DPA is an
interceptor unit intended for use with any pulse-width modulated valve (such as
boost control solenoids, idle speed control valves and fuel injectors) and gives
the user up 128 points of adjustment across the full operating range. It can be
used to drive a valve parallel to any existing ECU pulse signal (to drive an
extra injector) or it can be used to intercept and alter an existing pulse
signal. There are also some other applications and real-world DPA tuning
experiences discussed in this sizeable 13 page chapter.
Note that the Digital Pulse Adjuster is relatively complex to assemble and
can be set only via an extra-cost handheld controller – which we’ll discuss in a
The Digital Fuel Adjuster (DFA) operates in a similar way to the Digital
Pulse Adjuster, except it modifies DC voltages. As its name implies, the DFA
allows you to alter the fuel mixtures of your car by modifying the output of a
voltage-type airflow meter or MAP sensor. This simple to use kit looks set to
revolutionise the way the average enthusiast tackles ECU mods in their mildly
modified streeter. Not only does it allow you to revise mixtures with your
existing set-up, it also allows you to change to a bigger airflow meter and/or
injectors and realign the load input to achieve the appropriate mixtures. With
only one input and output this is simplicity itself, although you must take
extreme care while tuning. The kit is also relatively difficult to assemble.
Although intended for fuelling adjustments, the DFA can also be used to alter
closed-loop operation by intercepting the oxygen sensor output or to overcome
turbo boost cuts (by limiting the voltage from a load sensor). Seventeen
pages of the book are invested in this chapter.
The chapter on the Independent Electronic Boost Controller (IEBC) is one
anyone with an old-school non-electronic boost control system should look at.
The IEBC gives fully programmable electronic boost control with two separate
boost maps allowing different peak boost levels and boost curves. The IEBC
requires purchasing a suitable 12V solenoid which is pulsed on the basis of
injector duty cycle. Unlike any other system we’ve seen, this gives load-based
boost control. The IEBC is similar to the DPA in assembly and, again, requires
programming via the LCD Hand Controller. Note, however, this one isn’t for
beginners – if you’re not completely familiar with the concepts of boost control
system, you’re probably out of your depth.
A short chapter is dedicated to the all-important LCD Hand Controller, which
is used to tune the Digital Pulse Adjuster, Digital Fuel Adjuster and
Independent Electronic Boost Controller kits. Once you purchase and assemble the
controller, it can be employed to tune each of the kits – you only need one hand controller.
Another chapter gives you a circuit board design that allows the three mentioned
kits to be used in any car that uses peak-hold injectors.
Another interceptor covered in the book is the Speedo Corrector. The Speedo
Corrector is wired in between the vehicle speed sensor and ECU or between the
ECU and speedo. The unit allows you to alter the indicated road speed in 1
percent increments - it’s ideal for anyone changing diff ratio, tyre diameter
and correcting the standard speedo error. For the more creative among us, you
can also modify the speed input signal for the power steering or transmission
The Nitrous Fuel Controller should be a great way for anyone running a ‘dry’
nitrous set-up to save money and achieve a great end result with regard to the
fuel enrichment system. This kit lets you fit an extra fuel injector (or more
than one, if required) that is pulsed directly from the unit. The injector duty
cycle is adjustable to achieve the correct on-nitrous fuel mixtures. Note that
there is no variable input – it’s a constant flow system just like the nitrous
The Nitrous Fuel Controller can also be used to control electric pump and fan
speeds (up to 10A). It is a relatively easy kit to build.
The final chapter is on the Intelligent Turbo Timer. This is a particularly
clever idle-down system that monitors how hard you’ve been driving in the 7 minutes
before switching off the ignition. The unit has an adjustable maximum idle-down
period and depending on recent output voltages from the airflow meter or oxygen
sensor, it decides on the appropriate idle-down period (which is below your
preset maximum). It can also be configured to bypass engine immobiliser systems.
This is a relatively easy kit to build and is recommended for anyone in the
market for a turbo timer.
Performance Electronics for Cars is
unquestionably a groundbreaking book - it details hands-on solutions to
electronics-related problems that have largely gone unsolved.
Criticisms? Well, a ‘Difficulty Rating’ would be good for anyone pondering
whether to tackle assembling a kit and the layout of the text is sometimes
disjointed. There is also no discussion of kit prices and there’s little
indication of where they are available from – only a small breakout box in the
index page and advertisements on the cover pages.
The price is also a shock for anyone looking to spend some loose change on a
magazine – retail price is AUD$19.80. Fortunately, it has the feel of a high
quality publication – its square-bound, there are plenty of vehicle manufacturer
diagrams, coloured diagrams and quality all-colour photography.
And as we keep saying, the content is also ground-breaking.
Footnote:Performance Electronics for Cars
co-authored by John Clark and Julian Edgar. Julian Edgar is a major contributor to AutoSpeed.