- Thank you to The Motley Fool
for sponsoring a portion of this video.
- California recently (upbeat music)
announced they won't allow cars
with modified on ECUs on their roads.
Modifications which affect emissions are already illegal,
but now even ECU mods that don't affect emissions are.
And I have a scientific mindset
so I wanna see the evidence that modified ECUs
are actually bad for emissions.
So I did my own research and no,
that doesn't mean I Googled it.
I spent thousands of hours,
decades experimenting in the lab,
asking the tough questions that no one wanted to ask,
studying ECUs and their effects.
(music stops abruptly)
Okay actually,
I asked a bunch of experts to explain it to me.
I don't know everything guys.
I'm the smartest guy in Florida,
but that doesn't really mean a lot.
So drawing (upbeat music)
on their decades of experience,
we're gonna take a closer look at ECU modifications,
figure out the benefits and the risk of modifying them,
and see how ECU tuning is actually done.
Cali, I love you,
but you might be on the wrong side of science with this one.
Let's figure it out.
(upbeat music)
- Thank you to The Motley Fool (upbeat music)
for sponsoring a portion of this video.
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Let's go back to the show.
Thanks to Motley Fool
for sponsoring that portion of this video.
(electronic jingle)
- In a modern car (jazzy music)
with loads of electronics
the ECU is the central computer
that controls nearly everything,
but when they were first introduced in the '70s and '80s,
ECUs only cared about three things, air, fuel and spark,
but car enthusiasts care a lot about air, fuel, and spark.
So it wasn't long before they were tuning ECUs.
Tuning is just modifying engine systems
that control the amount of air and fuel
and timing of that spark.
In the old days, that meant physically changing things
like replacing fuel jets in a carburetor
or fiddling with a distributor.
Mechanical controls only have so much adjustability though.
So tuners and even manufacturers
often had to sacrifice easy drivability
or emissions for power.
Automotive engineers figured out
that you could reduce those trade-offs
and get more precise control over air and fuel and spark
by using electronic control.
So the carburetor was replaced by fuel injection
and the distributor with ignition coils.
Then they added a computer because that could be programmed
to alter air-fuel ratios and spark timing on the fly.
And thus, the ECU was born.
(baby cries)
And with it, so was ECU tuning.
A lot of enthusiasts want maximum power,
but ECUs from the factory aren't tuned for that.
So to get more power, tuners did what they've always done,
they modified the system controlling air, fuel, and spark,
but instead of turning screws or swapping parts,
tuners we're now writing code.
(electronic music)
Code.
Tuners were now writing code.
Like every computer, (jazzy music)
an ECU receives input and generates output
based on its program.
The earliest ECUs had their program stored on chips
that were soldered onto their circuit boards.
Modifying an ECU required physically replacing a chip
with one containing a different program.
That's where the term chipping or chip tuning comes from.
And those early programs,
they weren't all that sophisticated.
A lot of modern tuning is still based around some ideas
from the early days, like maps.
Those are tables where the X and Y values correspond
to inputs from vehicle sensors
and modern ECU's inputs can come from a hundred
or more sensors, but in the early days,
inputs were often limited to airflow, throttle position,
engine RPM, and exhaust gases.
The individual cells of maps contain output values
and early ECU programs were often based around a fuel map.
That's, well, let's hear it from an expert himself.
So what exactly in layman's terms
is a fuel map and how do you use a fuel map when you tune?
- Okay, so if we were talking, say like a standalone ECU
or a more do-it-yourself control unit
to control the particular engine, the most basic map
would be injector pulse width versus load,
which in most cases is just boost versus RPM,.
and at that particular load point,
you tell the ECU to command
X amount of injector pulse width
and it equals an AFR that you want.
- The point of a custom fuel map
isn't to dump as much fuel as possible into the engine.
Oh no, how much fuel your engine can burn
is limited by how much air it's getting
and that's why engine load is derived from sensors
that detect air flow or throttle position.
The ECU controls the injector pulse
to fine tune that air-fuel ratio.
The stoichiometric air fuel ratio for pump gas
is around 14.7 to 1.
That's 14.7 parts air for every 1 part fuel.
That's theoretically the perfect ratio
where all of the oxygen and gasoline combust,
releasing all of the fuel stored energy,
but that ratio assumes the air and fuel are perfectly mixed
and in the real world, that doesn't happen.
If you feed an engine with perfect ratio,
the actual distribution of fuel molecules
will vary inside the cylinder.
Some areas are gonna have more,
leaving some fuel unburned after combustions.
Others, they're gonna have less,
leaving some oxygen after combustion.
To compensate for that imperfect mixing,
a tuner can reprogram the ECU to inject extra fuel,
targeting a ratio around 13 to 1.
A slightly rich ratio, meaning there's more fuel,
ensures that there's enough fuel
for all of the oxygen to get used up.
That creates the largest possible combustion reaction
and produces the most power.
But, some of that extra gas doesn't get burned.
Manufacturers, they don't tune cars this way,
they compensate for imperfect mixing in the other direction
using a slightly lean ratio of 15 or 16 to 1.
That's because unburned gas is bad for fuel economy
and a slightly lean mixture ensures
that no gas goes unburned even if that means less power.
So, the ECU controls the amount of fuel
getting to the engine and that can be tuned
based on the amount of air
to maximize power or fuel efficiency,
but most ECUs have control
over the spark or ignition timing too
and that plays an important role in power as well.
The spark that sets off (jazzy music)
combustion needs to happen
near the end of the compression stroke,
a little bit before the piston reaches top dead center.
That's because combustion takes time to travel
from the ignition point at the spark plug
to the crown of the piston.
To make the best use of the combustion's energy,
you need the flame front to reach the piston
just as it's changing direction for the power stroke.
If you wanna learn more about the four cycles of an engine,
click here to watch this sweet music video
about sex, squeeze, bang, blow.
But ignition timing isn't controlled by a clock.
When the spark plug fires is based on the position
of the engine's rotation.
For example, around 10 degrees before top dead center,
the distance and speed the flame front travels
is always the same, but the speed at which the piston
is moving changes based on engine speed.
That means as revs increase,
so does the number of degrees before top dead center
the spark need to happen to achieve maximum power.
ECU tuners, they will sometimes advance the ignition
by several degrees to ensure they're getting everything out
of each combustion, especially at high revs.
Now the risk to advancing timing too much
is detonation.
That's when fuel ahead the flame front ignites prematurely
due to rising heat and pressure inside the cylinder.
Detonation creates shockwaves that can damage the engine.
You can actually hear this happening
and that's why detonation is sometimes called knocking.
So to avoid this, manufacturers tune ECUs
with conservative ignition timing, sacrificing some power.
So, ECU tuning can increase power
by altering spark with ignition timing
and by adding more fuel with longer ejector pulses.
All that's left to figure out
is how the ECU can add more air
and for a lot of engines,
it can't. (rock music)
You'll sometimes hear people describe engine as air pumps
and the more air an engine can pump,
the more power it'll make.
Remember, we got that sweet equation,
more air plus more fuel equals more power.
And air flow in older cars was often limited
by their intake or exhaust
which are restricted for noise or emissions reasons,
but those systems have drastically improved.
And in modern cars,
the amount of air that engine can pump in really is limited
by two other factors, there's the engine's displacement,
which an ECU obviously can't do anything about,
and there's the density of air coming into the engine,
which an ECU also can't do anything about
unless that engine has a turbo,
we talked to a lot of different tuners to make this episode
and the one feature they all agreed was nearly essential
for ECU tuning to make big power: forced induction.
(Jeremiah mimics engine)
That's because a turbo's only job
is to increase the density of air being fed to the motor.
Denser air means more oxygen in the same amount of space.
You add in more fuel to that, which we know the ECU can do,
and you can produce more power.
But with an increase in density
comes an increase in pressure and temperature
and if either of those get too high,
that can damage your engine.
So a factory tuned ECU, it limits a turbos boost pressure
to a safe PSI value.
And what you've seen so far is really just the basics
and 20 or 30 years ago,
that might have been all you needed to know
to start tuning yourself.
Modern tuning is a whole new world with more variables,
more precision, and more expertise needed to do it right.
What are the major things you can change with an ECU tune?
- Wow.
So not only just torque and horsepower at peak values,
but all the drivability,
you can do quite a bit of sound tuning, fuel economy,
the torque model, as I'm bridging this,
correlates to this particular map.
They have to get funneled
through what's called relative filling
or commanded relative filling, commanded torque out,
knock intervention, hexadecimal fuel mass,
A2L valve, basically, WinOLS, relative filling intervention.
- ECU tuning is super complicated.
Modern cars can have hundreds (jazzy music)
of sensors delivering inputs to the ECU.
Things like wheel speed, steering force,
even whether the car is on level ground or not,
all become input for a modern ECU.
Not only that, ECUs are part of an entire network
inside your car, including dedicated computers
that control the transmission,
separate ones for safety features like stability control,
and others for comfort features like power windows.
These all have to communicate with each other
and part of ECU tuning
is knowing how all those systems play together.
We also learned that there are lots of reasons
why cars are de-tuned from the factory.
Cars are sold in many parts of the world
in different parts of the country.
That means a car has to perform at sea level,
at 12,000 feet of elevation, and everything in between.
It also has to perform in the heat of Death Valley
or the cold of Alaska.
And it needs to keep working if the owner uses crappy fuel
or floors it at every stoplight when they take off,
Nolan's Sykes.
Cars are expected to live hard lives
so they come with ECU tunes that play it safe,
but that also makes them tuneable.
The people we talked to said that they looked
at two things in an engine.
First, is the ability to flow lots of air,
being a good air pump
and that means having an unrestricted intake,
head and exhaust, and most importantly, a turbo.
The second thing is being built for durability.
We did a whole B2B on engines that are overbuilt
and the people we talked to for this episode
said they look for pretty much everything we talked about
in that episode.
They also repeatedly talked about the big 'ol-
what's the thing in the room?
- [Cameraman] Elephant?
- Yeah, thank you.
They also repeatedly talked (jazzy music)
about the big old elephant in the room, emissions equipment.
Several mentioned that some of their ECU tunes
have performed better in emissions testing
than a factory tune.
Disabling emissions equipment
is actually detrimental to tuning.
The systems of sensors of modern cars
are so highly integrated
that the same ones keeping track of emissions
are essential for optimizing performance.
What matters most for emissions
is that the exhaust comes out clean
and that happens because of good catalytic converters
and optimized combustion, something tunes are very good at.
So there's your crash course in ECU tuning.
A long time ago, enthusiasts were trying to use ECU tuning
to get around restrictive emissions equipment,
but times change and now that same equipment
is essential for tuning itself.
So is a ban on ECU tuning supported
by the best available evidence?
I don't know that it is.
The worst consequences (upbeat music)
may not even be for us enthusiasts
because banning ECU tuning effects an entire industry
with many small businesses and smart innovators,
the same people who helped us make this episode.
If an ECU tuner wants to make their modification legal
for use on California roads,
they have to spend thousands of dollars for certification
and many small tuners simply can't afford that.
Thank you guys so much for watching this episode of B2B.
Do you live in California?
Are you mad that they're banning your modified ECU?
Do you not live in California and don't care?
Let me know down in the comments below.
Thank you so much for watching B2B.
We love you guys.
Follow us here at Donut on Instagram at Donut Media.
Follow me at Jeremiah Burton
and until next week, bye for now.