- If you're interested in turning a late model car,
then the technique of reflashing
is one of the most common
and most powerful ways of doing so.
In this first lesson,
we're going to take a look at what reflashing is.
Let's jump in the car and check it out now.
We're on the Dyno here with this 2013 ZL1 Camaro.
It's powered by a 6.2 litre
supercharged GM LSA engine,
which is very popular in the aftermarket
for tuning modifications.
Before we get too far into anything though,
let's just do a power run on the Dyno
and see what happens.
Okay, we've got our engine running
in fourth gear on the dyno.
We're going to do a power run between
about 1500 and about 6000 RPM.
I'm going to go to full power now, full throttle,
and then we're going to perform our run.
So that's our Dyno run complete,
and we can see from the Dyno's screen
that we've made 351 kilowatts,
or 471 horsepower at the rear wheels.
The components we are interested in
here on our Dyno plot,
on the bottom we have our green line,
which is our power in kilowatts.
The axis on the bottom shows us both
engine RPM as well as road speed.
Above we have our red line which has our air fuel ratio
or lambda plot which shows us how much fuel
we're adding to the engine.
So that's what the Dyno plot looks like.
Let's jump into our scanning software,
which I ran during that particular Dyno run,
and see what we've got to see there.
For this particular demonstration,
we're using the HP tuner's VCM suite software,
and in particular I scanned that Dyno run
using the VCM scanner software.
So here we have our plot of all the parameters
that I'm interested in viewing.
At the top here we can see have a couple of parameters,
we've got our engine RPM in red,
and if we look at the chart logout
we can see that our run was performed across this area.
So the start of the run you can see
that we're sitting at about 1500 RPM,
and at the end of the run you can see
that we got through to 6000 RPM.
At the same time we're also logging
and check the duty cycle
and our road speed on the same chart.
Moving down though, we also have an area here
of our chart that's going to give us
a lot of valuable information when we're tuning the engine.
In this particular chart we've got our ignition timing,
and you can see these red spikes.
These correlate to the computer's knock control system.
So all of these spikes are indicating that
during that Dyno run the engine was actually suffering
from some knock, or detonation,
and the engine was being protected by the ECU.
If we move down we also have our air fuel ratio
or lambda and we have two plots here.
We have a green line which is our
commanded air fuel ratio lambda.
This is the air fuel ratio that the ECU is requesting.
And in pink we have our measured air fuel ratio,
which comes from a wide band sensor in the exhaust.
So this is the sort of information we're using
when we're reflashing a PCM or ECU in a car
in order to optimise the tune and make more power.
Now while we've just performed this demonstration
here on our mainline chassis Dyno,
a little later in the series we are going to talk about
how we can tune using the technique of reflashing
out on the road without the benefit of a Dyno.
So if you don't have access to a Dyno,
don't worry, there's still some great information
in this series that's going to be applicable to you.
Let's rewind now,
and we're going to talk about what reflashing is.
Now if we were modifying a car perhaps 10 or 15 years ago
that was fitted with electronic fuel injection,
the technique of altering the tuning --
and by tuning I'm talking about the fuel delivery
and the ignition timing --
we would have typically fitted
an aftermarket standalone ECU.
And this allows us to completely control
the fuel and ignition that's being delivered to the engine.
Standalone aftermarket ECUs are a universal system
that we can wire in and fit to just about any engine
you can imagine.
These days with our modern vehicles though,
this is a little bit more tricky.
In our modern cars such as this 2013 Camaro,
we've got a range of different electronic modules
in the car and these rely on communications
between the different computer systems.
What this means is it's no longer as easy to remove
the factory-fitted engine control module
and fit an aftermarket standalone ECU.
If we do this we may well be able
to control the engine and make it run
but aspects such as the 6-speed automatic transmission
wouldn't work,
it wouldn't change gear,
and we even have problems with aspects
such as the air conditioning
or the instrument cluster not working.
So on our modern vehicles it's very difficult
to fit a standalone ECU.
That's okay because the technique of reflashing
gives us a great and really powerful option.
On many cars that were built after
approximately the year 2000,
we can now modify the tune data
held inside the factory ECU
using the technique of reflashing.
Reflashing involves us fitting an interface
between a laptop and the OBD2
or diagnostic port fitted to the car.
And this allows us to read the factory data out of the ECU.
Then we can modify it,
and once we've modified it we can then write back
into the factory ECU or "reflash the ECU" as it's known.
And when I'm talking about reflashing in this context,
I'm talking about us custom-mapping the engine,
so we're making changes on the Dyno
or on the road to suit the specific vehicle we're tuning.
I'm not talking about downloading an off-the-shelf tune
or a mail-order tune and flashing this into the PCM or ECU,
we're actually making specific tuning changes.
For a really quick example of this,
let's take a look at the HP tuner software.
This is our high octane spark map.
We can see that we have an axis of airmass
on the vertical axis,
and we have an axis of engine RPM
on the horizontal.
The numbers inside this table, understandably,
are our ignition advance or spark advance values.
We can see this table in a way that makes sense
to us as tuners and allows us to make changes.
Now let's talk about why we may want to reflash
our ECU in the first place.
Understandably if we're making really dramatic changes
to our engine configuration,
such as perhaps fitting a turbocharger
or a supercharger to a naturally aspirated engine,
or maybe switching to a more aggressive camshaft,
in that case these dramatic changes
to the engine configuration
are going to require us to change the fueling
and the ignition timing to suit.
This is going to mean that reflashing
or some modification to the tuning is essential
if we want to either get the most amount of power
and torque out of the engine,
or for that matter even ensure engine reliability.
On a slightly more standard engine, though,
there can still be advantages to reflashing the ECU
and optimising our tune.
I'm going to just talk about why that may be.
As an example, most manufacturers will be shipping
their cars and selling them to countries
all around the world,
and this may involve the engines
running on various grades of fuel,
and under various operating conditions.
I'm talking here about atmospheric temperature and pressure.
The tuning technique the the OE manufacturers use then
is to provide a conservative tune
so that they can ensure the reliability
and safety of the engine regardless
what the operating conditions are.
For us in the aftermarket though,
using the technique of reflashing
we can optimise those tuning parameters
to suit our exact operating conditions.
Often this can result in great increases
in power, torque, and fuel economy.
Of course the potential gains are magnified
when we start making hardware changes
or modifications to the vehicle as well.
So now we know what reflashing is,
and we know why we might reflash.
Let's talk about the software options
we have for performing this task.
One of the most common questions we get is
"What software should I use to reflash my ECU?"
And the answer is that there is no single
universal piece of software that you can use
for reflashing every type of car or ECU.
We need to choose the software
based on the particular car we're trying to tune
and for any car there may be
more than one software option available.
This means we need to research our options
and find the one that's most suitable for us.
Now that we've talked about the software options,
let's talk about what we're actually trying to achieve
when we're reflashing the ECU.
I know that a lot of novice tuners,
particularly those that are new
to the world of reflashing,
get a little bit confused and overwhelmed
when they see the complexity of a modern factory ECU.
I think it's important to always break it down
and look at what we actually are trying to achieve.
And when we remove all of the complex functions
of modern engines and modern ECUs,
it really comes back down to two main aspects
we're trying to control.
One is the fuel delivery,
and the other is the ignition timing.
And regardless what ECU,
what engine,
and what tuning platform we're using
to make our changes,
the way that the engine responds
to both of these aspects,
fuel and ignition,
is always going to be the same.
When we can focus on this,
and break down the complexity of the system,
everything starts making more sense,
and looks a lot easier to understand.
Further into these lessons
we're going to have a look at
exactly how we can approach both of these aspects,
fuel and ignition tuning using reflashing platforms.
One of the things we need to get familiar with
if we're reflashing vehicles
is that the maps we have available,
the way these maps look,
and the way we need to manipulate them,
is going to depend on the particular ECU we're reflashing.
Now this isn't because the software manufacturers
are purposely trying to make our life difficult,
but more because the way the software works
is going to be dependent on the ECU,
and the way the ECU is structured.
Now this is because every vehicle manufacturer
has their own particular ideas
on how as best to control fuel and ignition timing
with their own ECU.
And hence we see quiet big variations
from one ECU platform to another.
And this is referenced in the way the software works.
We're gonna have a look at a couple of quick examples now,
and see what these tables might look like.
Let's start with our ZL1 Camaro and the HP Tuner software
which we've already had a brief look at.
Now if we wanted to influence the wide-open throttle
air fuel ration on the Camaro,
in this case what we'd be doing is trying to adjust
what's known in GM lingo as the "power enrichment table."
We can see here I'm on the Power Enrichment tab,
and we've got a variety of tables or parameters available.
The one I'm interested in here is the
"Power Enrichment EQ Ratio Gas."
And what this really means is
the equivalence ratio target for petrol.
If we open this up we can see
we have a two-dimensional table here
of engine RPM versus equivalence ratio.
Equivalence ratio is really just the inverse
of our lambda target.
Not gonna get too hung up on that now,
'cause we're going to have a look at this
in more detail in a future lesson.
All you really need to know is that
the numbers in this table define the target air fuel ratio
when the engine's operating in what's known
as power enrichment.
Now it might be quite strange to see
a simple two-dimensional table
to define our air fuel ratio targets.
This is an important point to look at
the way a factory ECU works.
Factory ECUs predominately use a mass airflow sensor.
With a mass airflow sensor,
the ECU is directly getting input
telling it how much air,
or what mass of air in grammes,
is entering the engine at any particular time.
The whole key to the way the factory ECU works
is the accuracy of this mass airflow input to the ECU.
Now the reason for that is if the ECU knows
what mass of air is entering the engine,
and it also knows what mass of fuel
the fuel injectors can supply,
then if we tell it what air fuel ratio we want,
it's very easy for the ECU to accurately calculate
how long to open the injectors for,
in order to achieve exactly our desired air fuel ratio.
And you'll be surprised at how accurately
some of the late model factory ECUs
can control this air fuel ratio.
Hence, making adjustments to our targets
is often as simple as adjusting this power enrichment table.
Now we've look at the HP Tuner software for GM vehicles,
let's have a look at some other examples.
Here I've got the Ecutek Tuning Package,
and in this case we're looking at the tuning package
for the Toyota 86 Scion FRS and Subaru BRZ platform.
Now you can see on the left hand side
we've got a tree-style menu structure
which shows us all of the available maps that we can adjust.
I've just got two maps here to have a quick look at.
At the top you can see we have our fuel map,
and below that you can see we have our ignition base map.
Now these maps as we can see
this time are three-dimensional.
For both of these maps we can see that
the horizontal axis is called "engine load."
So this is the engine load axis.
And again in this case the ECU
is relying on the input from a mass airflow sensor
and the load axis here we can see
is labelled as "grammes per revolution."
So again the ECU is looking at the mass air flow
in grammes per revolution.
Our vertical axis is relatively traditional,
you can see we have engine RPM.
So again for our fuel table,
much like our GM ECU,
we can see we're directly requesting air fuel ratio targets.
To the right we have a three-dimensional
graphical representation of that table,
so that we can see the general trend
or shape of that particular table.
Below we have our ignition map,
and again we have the same axis,
and this time the values inside our ignition map
define the ignition timing,
the advance angle that we want.
Again to the right we have a three-dimensional
representation of our ignition table.
Lastly, let's have a look at the
Cobb Accessport Software for tuning a Porsche ECU.
In this case, it's a Porsche 996 Twin Turbo.
I've got one table up here just to have a quick look at.
This is our commanded air fuel ratio or lambda table.
We can see in this particular table
we have axis of engine RPM on the vertical axis,
and the horizontal axis is labelled as
relative load in percent.
This is simply a calculation based, again,
on the mass air flow into the engine.
We can see that the values inside this table
are our commanded air fuel ratio values this time in lambda,
and again below just like in the Ecutek software
we can see we have a graphical representation
of that particular map.
So as you can see there we've just look at three platforms,
and we can see there's three quite different ways
of representing these maps and adjusting this data.
The important point to understand here
is that regardless what ECU we're reflashing,
and regardless what software we're using
for making our changes,
what we're trying to achieve is always the same.
It's simple optimising the fuel delivery,
and optimising the ignition timing.
Now that we've had an introduction
to what reflashing is,
and you understand how the process works,
we can move on and in the next series of our lessons,
we're going to look at fuel tuning in a little more detail,
and we're going to see how
we can actually make these changes,
and what effect they have on the Dyno.
I hope you can join us for the next lesson.