This article was first published in 2008.
I have been modifying cars for about 20 years, doing it first as an enthusiast and then latterly as a journalist writing about
I have rebuilt a BMW engine; turbocharged and
intercooled a naturally aspirated engine - including making my own turbo exhaust
manifold; I’ve upgraded intercoolers and turbos and exhausts and radiators. I’ve
done full suspension makeovers, aerodynamic modifications and rebuilt an auto trans. In the distant past I even internally modified an auto
trans valve body to change shift behaviour, developing the whole modification
myself. I’ve got a home workshop with a lathe, mill, bandsaw and lots of other
But I have to say: DIY electronic modification
of cars beats mechanical mods hands-down for cheapness, ease of modification and
With electronics you can change turbo boost curves
to get more performance at the bottom of the rev range – and the top as well.
You can improve fuel economy and alter the way the car feels to steer. On cars
with active torque split four wheel drive, you can in ten minutes and for under
$100 make a greater improvement to handling than spending thousands of dollars
on new suspension bits and tyres.
Nothing – simply nothing – beats DIY electronic
mods. In fact, if I feel an inadequacy in a car I am driving, I now think: “What
can I change electronically?” rather than first considering getting out the
My Honda Insight hybrid is one of the most
fuel-efficient cars in the world. But for a cost of under $5 I have made
electronic mods that measurably improve fuel economy.
When I owned a twin turbo, all-wheel drive Nissan
Skyline GT-R, I built a torque-split controller that allowed the front/rear
active torque split to be altered by a driver-operated knob. You could change
the handling balance literally from corner to corner. In the rain, the handling
was simply that of a different car.
When I owned a Lexus LS400, I found the steering
light and lacking in feel. But by using a single adjustable electronic
component, I was able to dial-up an increase in the weight of the
electronically-controlled steering that gave the driver far better control on
the road. By using a second technique that made use of an electronics kit, I was
able to make the steering lighter in carparks and heavier on the road, in fact
getting increasingly firm as speed increased!
A long time ago I owned a 660cc Turbo Daihatsu. It
featured a big turbo, water/air intercooler and larger injectors. It got to 100
km/h in about 6.9 seconds. Making the standard ECU work with the big injectors
cost less than $5 – and the car had perfect driveability.
None of these modifications involved years of
study at breaking into the software of car computers; none of these mods was
expensive. Most just involved simple measurement of car systems, some thinking,
and then testing different modifications.
And all the modifications were extremely
Not the Answer to Everything
DIY electronic modification is not the
answer to everything. You can’t change the boost curve of a turbo that isn’t
there, or use electronics to improve the flow of a restrictive exhaust. But, in
cars that increasingly use electronics to control nearly every system – and in
the future of hybrid and electric vehicles, to power the car as well – having
electronic modification skills in your armoury dramatically increases the
likelihood of doing great DIY car modifications.
Simple electronics of the sort that is being
described is not a closed book. It does not require years of
study, formal training or intrinsic brilliance. You do not need an
understanding of the whole field of electronics to be effective at making car
electronic modifications – you can simply make modifications based on the
understandings you have. (After all, that’s just like mechanical mods – how
many modifiers would have the ability to design a camshaft from scratch?)
Even an understanding that you can develop in half
an hour will allow you to do mods that would otherwise cost hundreds of dollars
more if done mechanically – and that’s if they’re even possible to do
In this series we will start from the beginning:
you don’t need to have any electronics knowledge at all.
We will introduce concepts that can be built on
one another, resulting in a frame of reference that remains the foundation for
everything that follows. But that doesn’t mean you need to wade through
thousands of words of theory before you can start making modifications. In fact,
in each following part in this series we will cover a concept and then
immediately apply it to a real world car modification.
You might not want to do that particular
modification, but look at the example closely so that you can see how the
Don’t fool yourself – if you don’t understand it,
don’t pretend to yourself that you do! Learning requires honesty as well as an
open mind: there are heaps and heaps of tossers who skim something, get a vague
gist of what it was all about, and then think they know it.
One really good way of self-assessing whether or
not you have learnt something is to say to yourself: can I now explain this idea
to someone else? As a teacher and journalist, I know this approach very
well – if I can’t explain a newly-learned concept to someone, then I don’t
understand the concept.
Electronics is the sort of subject where it is the
sequence of ideas that is important. In this series, none of the individual
ideas will be at all hard; it is the understanding how those ideas stack
together that is vital.
If you do mechanical mods, you need spanners and
sockets and a hammer and screwdrivers. If you do electronic mods, you also need
You can try doing electronic mods without any
special tools, but it’s just making things hard for yourself. Like using a pair
of pliers to undo a bolt, rather than a socket and a breaker bar. You round-off
the bolt and then decide you don’t really want to mechanically modify your car
Your need three major pieces of equipment:
The key piece of equipment is a multimeter. A
multimeter is a test tool which can measure a variety of different electrical
factors - at minimum: volts, ohms and amps. In addition to these measurements,
it helps if the meter can also display:
Another very useful function of a multimeter is a
'peak hold' button. As the name suggests, the meter will retain on its display
the max value measured. Especially when working by yourself on the road, this
allows testing without having to constantly glance down at the meter.
The best place to buy a multimeter is from an
electronics store. While automotive parts suppliers stock multimeters, they can
be up to double the price for meters with just the same quality and features.
Note that pretty much any digital multimeter will have sufficient accuracy for
car use - buy on the criteria of price, features and warranty. Because of the
huge decrease in prices over the years, it's not worth buying a multimeter
secondhand - many times they are above new price!
Next on the list is a soldering iron. A general
purpose mains-powered iron (eg a 25 or 40 watt design) will perform most
soldering tasks on a car - and also can be used to assemble electronic kits and
work with individual components.
However, if you can stretch for the extra dollars,
a temp-controlled iron is a better proposition. Not only do they - as the name
suggests - allow you to dial up an appropriate temp for the job, but they
usually are configured with a base station and a remote iron that's linked to it
with a supple cord. The lighter iron makes it a lot easier to use, you get an
inbuilt stand and a tip-cleaning sponge is usually also provided.
And don't forget to use solder designed only for
A variable supply is, I think, an absolute
must-have. It’s especially useful if you're building something and want to test
it before it gets into the car.
A variable power supply can output variable
voltages and in some cases, variably limit the current flow as well. At
realistic prices you're more likely to find power supplies that can supply
currents up to 3 amps and have an output voltage range of 0-20 volts.
Most important is to have a power supply that has
built-in digital meters to show the current being drawn and the voltage being
supplied. Having this information instantly available (sure, you can measure it
with your multimeter - but then that ties up the meter) is extremely useful.
Also look also for fine and coarse supply voltage
adjustments (so much easier to accurately set the voltage) and the variable
current output facility. The power supply should also be completely protected
against overload, high temperature and short circuits.
Electronically modifying cars opens up a whole
world of incredibly cheap, very easy and highly effective possibilities. Don’t
Next: understanding circuits