In previous articles, I’ve said that
you can select your injector from a dropdown list. There are
currently 60 injectors in the list, so I thought it would be
appropriate to show some options to find your injector and
what other information you can gain from the injector
selection screen. Firstly, the injector selection can be found under
“outputs -> injector type” screen. The Modular ECUs
currently support up to 4 stages of injection and you can
select a different injector type for each stage. So each stage
has its own injector selection screen. Rather than searching through the list, you can
click on the “Search…” button next to the dropdown list. This
brings up a list of all the injectors we have characterised so
far, but as I mentioned it would be painful to search through
all of them. So instead it might be easier to do a search. For example if you know that the injector is a
factory Nissan injector, you can type “Nissan” into the search
bar, and all the Nissan injectors we’ve characterised so far
will appear. The application for each (ie where we’ve found
them – they may be in other engines or cars as well) is shown,
and it also shows what we call the nominal flow rate. This
isn’t what we’ve measured, it’s just how people refer to them
colloquially so that if you know what your injectors are
called by people in the community, you can verify it in this
nominal flow field. The standard fuel pressure in the factory
vehicle is also shown in the nominal flow field. To further help in identifying the injector, the
software shows the manufacturer’s markings on the injector,
both the manufacturer’s name and the part number. So if you
have some number on the injector, for example 2460 on the RX7
primary injector, you can type this into the search field and
see the injector appear in the search results. Of course a really useful way to identify an
injector is by a picture, so we show a picture of the injector
as well. The dimensions of the injector are also shown, in
terms of the nominal length (usually 60, 48 or 34mm) and the
top o-ring diameter (14 or 11mm) – or it will just say “side
feed” if it’s a side feed injector. Some other fields include the connector type, the
factory fuel system (manifold referenced or fixed fuel
pressure), and the person we need to thank for providing the
injector to characterise. If we have a serial or batch number
for the injector that we tested then that’s also shown. Another field shown is the minimum volume. This is
the minimum volume of fuel that in our estimation the injector
can reliably deliver. With some injectors, below this volume
they just don’t deliver fuel accurately, for example the curve
has a very steep slope – or worse, if the injector is
underdamped you’ll see oscillations in the fuel volume so a
lower pulsewidth can cause an increase in the fuel delivered.
We want to keep away from such conditions, so this field shows
the minimum volume that you can expect from the injector at
the rated fuel pressure. If you select a particular injector and click “OK”,
this will take you back to the main injector selection screen.
You’ll notice now that the settings for the flow rate and
offset / dead-time are no longer visible because they are hard
coded in the injector database in the ECU. A summary of the
information from the search screen is also shown on this
screen for your reference. After this we’d recommend setting the minium
pulsewidth to zero, and setting the minimum fuel volume
setting to the value displayed in the summary at the bottom.
The reason we don’t do this automatically is that we know some
people will prefer to do things manually; eg have the minimum
fuel volume set to zero and handle it in the fuel map, or use
a minimum effective pulsewidth instead. I’ve said it in other videos but I need to say a big
thank you to Paul Yaw from Injector Dynamics for his help with
teaching me how to characterise injectors accurately and in an
automated way. Without that I’d probably still be “pissing in
a bucket” in his words. And thank you to all who have lent or
sent injectors for me to measure – too many to mention but
they are all credited in the software. Thank you.