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Article:

One of my pet peeves is dishonesty, especially when it comes to business. I hate going to a store where a salesman is hovering, waiting to "help" me, because I know he will tell me whatever I want to hear to get my money.

This kind of salesman - the kind who will say anything to get your money - can be found everywhere. We are seeing them more and more in the performance market as internet sales increase. (It's easier to BS someone when there is no eye contact)

Several times a month we hear from a customer who was duped into buying what he or she thought was a genuine Injector Dynamics product, only to find out that's not the case. There are plenty of dishonest people who will offer "the same as ID injectors" thinking the customer won't know the difference.

Do yourself a favor and research the situation. Be sure you're buying from an authorized Injector Dynamics dealer, and that your injectors are all serial numbered.

From day one, every single ID injector has been labeled with a unique serial number. We use the serial number to reference over 450 points of dynamic flow data on every injector we sell, and we have data on file for over one hundred thousand injectors.

Until recently, that serial number was hand engraved on each injector, and many didn't realize what it meant or where it came from.

Starting in 2013, all injectors will have the ID logo, part number, and serial number laser etched on the body of the injector. This makes it easy for you to protect yourself and ensure you're not being taken advantage of.

You've worked hard for your money, don't let someone steal it from you.

Tony Palo - Injector Dynamics.

Watch the Engraving Process in Action on YouTube

Introducing the ID1300

When we let the cat out of the bag at the PRI show in November, we had no idea we would get the kind of response that we did.

Instead of answering questions about when it will be ready, we are hearing from dealers, and individuals who tell us that their build is on hold until they get their hands on them.

Well guys...we are as excited as you are, but we are also unwilling to release an injector until it is good enough that we can call it the best, without reservation, regardless of the application.

What we are willing to do is use this opportunity to tell you a little bit more about it, and how it came to be.

The ID1300 is the result of a technical partnership between Injector Dynamics, and Bosch Motorsport. This partnership allows us to start with a clean sheet of paper, to develop an injector with characteristics that will make it perform well in a wide variety of performance applications.

The ID1300 Offers

Compatibility with all known fuels.

Stable operation over a broad pressure range.

Low minimum fuel volume, capable of stoichiometric idle in small displacement engines.

Smooth controlled response at low pulse widths, allowing accurate linearization using all OEM methods (Ford, GM, Chrysler, Porsche, Subaru, etc.)

Coming soon to a dealer near you...

Paul's TechnoRant

Welcome to my first TechnoRant. This one will be mostly tech, with very little rant. Sorry about that. You'll have to pay attention, and maybe even do some math. Yikes!

You've probably noticed that some fuel injectors are rated in units of mass (lbs/hr, g/sec, g/min) while others are rated in units of volume. (cc/min, l/hr)

The purpose of this article is to explain what the various ratings mean, how they are determined, and how to convert between them.

The first step is to understand the difference between mass and volume.

Avoiding the complex, and putting it in terms that we can all understand, mass is a measure of "how much it weighs" while volume is a measure of "how much space it takes up."

Common measures of mass include: gram, milligram, kilogram, pound, and ton.

These are all a measure of "how much it weighs" and so not surprisingly, we take this measurement with a set of scales. Since these are all a measure of the same physical characteristic, we are free to convert from one unit of mass, to any other unit of mass. For instance, one pound is equal to 453.6 grams. One ton equals 2000 pounds, etc.

Common measures of volume are: cubic centimeter, milliliter, liter, microliter, cubic inch, cubic foot, and gallon.

Just as with units of mass, we are free to convert between units. One liter is equal to one thousand milliliters, one gallon equals 231 cubic inches, etc.

Converting from units of mass to units of volume, or the other way around, is not so straight forward, as the following example illustrates.

Using an ID1000 injector for our example, if we were to apply voltage to the injector for one minute, and catch the output in a graduated cylinder, we would find 1000 cc's, or one liter of liquid in the container. Based on this test, we could state that the injector has a volumetric flow rate of 1000 cc/min.

But what about the mass flow rate? To determine the mass flow rate, we need to weight the fluid. Putting this liter of n-heptane on the scales, and subtracting the weight of the container, we find that it weighs 684 grams.

Based on this result, we could state the mass flow rate of the injector as 684 g/min. Or, knowing that we can convert from one unit of mass to any other, we could state this in terms of g/sec (11.4) or lbs/hr (90.5)

The one thing we are not free to do is convert directly from units of mass, to units of volume.

Why? Because there is one piece still missing from the equation, and that one piece is the key to understanding the difference between mass flow rate, and volume flow rate.

So what would happen if we tested the injector with toluene instead of n-heptane? Anyone care to take a guess?

We would find that the two fluids are similar enough in viscosity that the graduated cylinder would still contain 1000 cc's of fluid, give or take a few cc's, and so the volumetric flow rate would still be 1000 cc/min.

However, once we take the container to the scales and weigh it, we would find that it weighs a whopping 867 grams. Based on this, we could state the mass flow rate as 867 g/min, 14.5 g/sec, or 114.7 lbs/hr.

To save you from doing the math, that is a 27% increase in mass flow rate as compared to the same test done with n-heptane!

So how could that be? Is it a 90.5 lb/hr injector, or is it a 115 lb/hr injector?

The answer is that it depends on the density of the fuel.

Intuitively, we all understand density, even though we may not have considered it's definition. For instance, we know that a piece of aluminum weighs less than an equal sized piece of steel, because aluminum is less dense than steel. Just as we understand that a bucket full of water weighs more than the same bucket full of feathers, because water is more dense than feathers.

Technically, density is defined as mass per unit volume. Mathematically, it is defined as mass divided by volume. If we divide our mass of toluene (867 grams) by its volume (1000 cc's) we get a value of .867 grams per cubic centimeter, which is a measure of its density.

While density can be stated using any units of mass and volume that we choose (lbs per gallon for instance) grams per cubic centimeter is most commonly used for automotive fuels, and is often referred to as "specific gravity."

Back to our example, the volumetric flow rate remains nearly identical for any of the common fuels in use (Ethanol, methanol, gasoline, etc) while the mass flow rate is dependent on the density of the fuel.

That being the case, it is meaningless to know the mass flow rate of the injector without also knowing the density of the fuel.

And that leads us to the next question...why would anyone rate the fuel injector in units of mass flow rather than volume flow?

The answer is that air fuel ratio is based on units of mass, not volume. When we state that the stoichiometric air fuel ratio of gasoline is 14.7:1 we mean 14.7 lbs of air for each lb of fuel, or 14.7 grams of air per gram of fuel.

As tuners of aftermarket engine management systems, we may be used to the "poke it with a stick" method where we add or remove fuel to achieve the target air fuel ratio, with no reference to either air or fuel mass.

This is in sharp contrast to the methods used by the auto manufacturers. The auto manufacturers reference air mass, whether they are using a mass air meter or the speed density method. The pulse width required to achieve the target air fuel ratio is then calculated from the air mass, and the mass flow rate of the injector.

Those of you with experience tuning factory ECU's are familiar with mass based injector flow rates, and after reading this far, you may wonder why they do not also specify the density of the fuel when stating the mass flow rate of the injector.

The answer is that it is a known quantity, as all of their calibrations are done using the same reference fuel.

Click here for full specifications of US Tier II Emissions Certification Fuel

The bigger question arises when we purchase aftermarket injectors rated in units of mass flow. The question is "Using what fuel?"

If the injector is intended to be used with pump gas, the mass flow rate should define the flow with emissions certification fuel, which was originally used by the auto manufacturer. If the injector is intended to be used with methanol, the mass flow rate needs to reflect that. The same goes for ethanol, FTW, C16, Toluene based fuels like Shell URT, etc.

As you can see, this gets confusing real quick.

The preferred method, for any injector intended to be used with a variety of fuels, is to state the injector flow rate in units of volume, and from that the mass flow rate can be calculated by the end user, if needed, based on the density of the fuel being used.

This is quite simple, as we have already learned that density equals mass divided by volume. Conversely, mass equals volume times density. We simply multiply our volumetric flow rate by our fuel density to arrive at a mass flow rate.

Example using ID1000, and Tier II Emissions Certification Fuel:

1000 cc/min times .742 g/cc equals 742 grams per minute. From here, we can convert to whatever mass flow units our engine management system requires.

To convert to grams per second, divide by 60 (742 / 60 = 12.4)

To convert to pounds per hour, divide by 7.56 (742 / 7.56 = 98.2)

And now we get to the rant...

It is critically important that the injectors be tested with a representative fluid.

The common practice of testing an injector with a low volatility mineral spirit based fluid produces erroneous results, because the fluid viscosity is much higher than gasoline.

Errors in the range of 8% to 15% are common, with a 1000cc injector flowing as little as 875 cc/min using these fluids.

Manufacturers of low cost injector test benches, who should know better, claim that the results are valid because their test fluid has a specific gravity similar to gasoline!

This is utter nonsense.

I can produce wheel bearing grease that also has a specific gravity similar to gasoline, but no one in their right mind would pump that through an injector, and claim that the results are accurate.

Next month, we are going to discuss the effect of temperature on fuel density, and how you can compensate so that your mixture does not lean out as the fuel gets hot.

I sincerely hope that you found this information helpful.

Paul Yaw - Injector Dynamics