today
we're going to talk about car tuning no
not cartooning but car tuning
how do you tune your car to get maximum
horsepower
and can you even tune modern cars
horsepower comes from explosions you
squeeze as much
air as you can into the cylinders add
just the right amount of fuel
ignite it with a spark and boom the mix
of air and fuel
or air fuel ratio determines how much
energy is released and how much
emissions are produced
car makers tune for the ideal air fuel
ratio
which is 14.7 parts air to one part fuel
but here's the thing that ratio might be
ideal for maximum economy and emissions
which is what the car makers want but it
is not ideal for maximum
power which is closer to 12 to 1.
this means your car is capable of more
power and that's where tuning comes in
the challenge is that cars have gotten a
lot more complicated and so has tuning
when engines first appeared the air fuel
mix was controlled by a carburetor
the simple device worked by sucking the
air into the engine along with the air
stream
adjusting the fuel to air mixture was
simple you fiddle with a few screws to
allow more or less fuel to enter the
engine
then you listen it's pretty much like
tuning a musical instrument
if it sounded right it was going to
drive right pretty simple
but it wasn't long before car makers
invented a more efficient way of
delivering fuel to the mix
fuel injection the carburetor doesn't
distribute the air fuel mixture evenly
which results in higher fuel consumption
than emissions
fuel injection delivers a fine mist
directly into each cylinder
so you get better combustion and less on
burn fuel
then to get even better fuel economy
engineers
needed to vary the ratio depending on
things like
altitude engine temperature and speed
but varying the spray mechanically was
pretty limited so things got
even more complicated carmaker started
working on electronic fuel injection
which needed a computer
electronic fuel injection uses sensors
to measure things like speed and
temperature
the measurements get fed into a computer
system
this system has saved settings that are
applied to different situations
these settings are known as maps or
tunes
and they're basically graphs that the
computer looks at when it analyzes stuff
so let's see how this works you get in
your car and start the engine
the car's cold a little sensor on the
engine measures the temperature and
sends a message to the engine control
unit or
ecu hey it's pretty cold over here
so the ecu sends a message to the fuel
injector hey spray more fuel
as you drive and the engine warms up the
same little sensor starts getting hot
so it sends a meshes to the ecu things
are getting hot here
at the same time another sensor sends
the ecu a message saying
the speed is currently 40 miles an hour
so the ecu consults its map
the map tells what the fuel ratio is
best given the heat and speed
then it instructs the fuel injector and
the amount of fuel to achieve that ratio
it was the challenges of fuel injectors
that drove the car into the computer age
the earliest version of the electronic
fuel injection system goes back to 1953
it was invented by the bendix
corporation but never used
then bosch brought out the jetronic
electronic fuel injection system
which used engine speed and a pressure
pad
by the 1970s and 1980s laws became
stricter on emissions and by the 1990s
almost
all cars had fuel injectors at least
here in the united states
today's automobiles have computers that
control everything
it's not just one computer but a
collection of electronic control units
that together are referred to as the
car's computer
some cars have up to 80 electronic
control units or ecu's that control
different electrical systems or
subsystems on the vehicle
typically the biggest processor is the
engine control unit we talked about
before
it's sometimes also called the engine
control module or ecm
this is probably so you don't confuse it
with the generic electronic control unit
it's not hard to get confused
there are just so many electronic
control units and modules
you can have powertrain control module
pcm
transmission control module tcm brake
control module bcm
and much much more they all talk to each
other via can which stands for
controller
area network it was developed in the
1980s by robert bosch
mercedes-benz was the first car maker to
use the canned system back in 1992.
can allows messages to travel together
on the same wire
that gives priority to more urgent
messages just like you get
all kinds of messages on the line
feeding your computer your
phone your video and they're all in the
same wire but the computers can make
sense of it all
so remember the engine control unit from
before
which sent messages to the fuel
injectors well those messages are pretty
important so are the messages from the
brake control module for example
but now you've also got messages from
the infotainment system like you
connected the phone to the bluetooth
and all these messages are traveling
around as fast as they can
it's pretty busy on the cannes highway
so what happens if there's a traffic jam
and the message can't get through
very good question this might be okay
for infotainment messages
you teenagers can't wait a few seconds
for their iphones to connect
but it's not okay when it's a message to
the brakes stop right now it's pretty
important
well that's where the can acts like a
traffic cop
it tells the infotainment system to back
off and waves the brake and other
priority messages through
so what does this have to do with tuning
well nowadays if you want to tell your
engine to do something you've got to do
it digitally rather than mechanically
and you do that via the obd port obd
stands for on or
diagnostics it's the access to the car's
computer
mechanics use devices that plug into the
obd port to see what needs to be tested
and repaired when things go wrong the
port is usually located somewhere near
the dash
an obd reader checks the trouble code
and then clears it from the computer's
memory when it's fixed
so it's key to fixing problems but it's
also the key to tuning your car
every decision your engine control unit
makes depends on how it was programmed
or tuned
like we mentioned before you could take
one car and give a completely different
character simply by changing the
software
on the ecm one character could have a
need for speed and be tuned for maximum
power the
other could be conservatively tuned for
maximum fuel economy
your car will come out of the factory
tuned for economy and reliability this
often means they made the performance of
the car
lower a different tune could make the
car go much faster
tuning means the right software and
knowing how to use it this
hacking art has become so advanced that
homebrewed
engine remapping software is available
to download for the brave and tech savvy
there's no shortage of devices that are
available to tune your car you can use
the software to read the current
settings modify parameters and then
write them to the computer of course
there's so much information and so many
parameters
that if you didn't know what you're
doing you could all drown
in data and if you did tinker you want
to make
really small incremental changes and
then test what effect they have in a car
it's also a very good idea to save the
original settings so you can revert back
to the standard factory map
most tuners have that device set in so
you can save them you know that
feeling when you push save on a document
that writes over the old document you
suddenly remember
one paragraph you should have kept you
don't want to have that feeling when
you're tuning your vehicle
but there's other things that can go
wrong too which is why we're flashing
this disclaimer
bad tunes can damage engines and be
dangerous to drivers
they can also shorten engine life lead
to greater fuel consumption
void the car's warranty and might even
be illegal
car manufacturers obviously don't want
you messing around
so ecu's have protection locks this is
also to prevent high-tech carjackers or
car hackers from plugging into your obd
port to steal your car
although pros can do it anyways they can
bypass just about anything
there are a lot of professional tuners
who will tune your car for you
you'd want to make sure their
credentials before you let them get
their hands on your car
in fact they wouldn't even need to touch
your car you can buy a programmer online
download your ecu file upload it to the
tuning company
then retune their flash or chip it and
send it back to you for downloading
or if you're on a budget their
performance chip plugins
on the internet as low as 50 bucks not
sure what you're really going to get
for that sounds like something we need
to test other companies have taken
advantage of the obd port as well
insurance companies use it to analyze
driving habits and give discounts based
on better driving habits you can also
put dongles on it to connect your iphone
to provide alerts
this includes making sure your teenager
keeps the speed limits
pretty much a telematics system be
careful about plugging dongles into your
car
think about your car as you would your
computer you'd be careful about viruses
and hacking on your computer
same applies to your car after all it
really is becoming a big computer on
wheels
which all makes modern tuning very
hard but it's not impossible if you want
my opinion tuning older mechanical cars
is more
fun it had more basic karma and feel
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