Injector End Angle Auto-Phasing Table

[Danny Cabral]

NOTE: I moved this segment of a different forum post to this new forum thread, because it warrants its own subject matter.
For more Injector End Angle information: Open the Holley EFI software & "Help" Contents (top Toolbar), and read the "Injector Phasing Instructions".

I especially like the "AND/OR" Switched/Sensor Input Triggers option (Inputs/Outputs ICF), the Target Air/Fuel Ratio "Graph", the Advanced ICF 2D Tables, the 2-Step "Spark, High Only" Rev Limiter, the 16x16 Ignition Dwell Table, the 16x16 Injector End Angle Table, and no more zipping & unzipping Global Folders (email attachment) is nice too!
http://documents.holley.com/techlibr...0_overview.pdf (Holley EFI V4 Software Overview)

[S2H]

The 16x16 Injector End Angle Table is great...the "Auto Phasing" portion of it, is not. Somebody screwed the pooch on that one, WAY out in left field. I highly recommend never using the "Auto Phasing" portion of it.

[Danny Cabral]

The 16x16 Injector End Angle Table is great...the "Auto Phasing" portion of it, is not. Somebody screwed the pooch on that one, WAY out in left field. I highly recommend never using the "Auto Phasing" portion of it.

Oh no! I don't have much engine run time on it (been doing drivetrain modifications), but what exactly did they screw up?

[S2H]

It's just way out of line with reality.

Tuning hundreds of cars a year, the numbers that get auto populated are just WAY out in left field.
You pretty much never want it to stop injecting fuel after the valve closes.
You always want it to stop injecting before the intake valve closes.
And their math often puts it ending after the intake valve closes.

[Danny Cabral]

You pretty much never want it to stop injecting fuel after the valve closes.
You always want it to stop injecting before the intake valve closes.

Thanks Scott. This makes perfect sense to me. So much so, that I decided to email a Holley EFI Engineer to inquire about this. He informed me nothing is wrong per se, with the Injector End Angle Auto-Phasing Table, because it simply programs each cell value at the same relative position (centering the injection pulse-width around the intake centerline). This is intended to "assist" the end user in populating the 16x16 Injector End Angle Table (as a starting point), not to "tune" the table. There are many variables that affect how well the IEA auto calculation is, but the most significant is how big the fuel injectors are. Smaller injectors that run at higher duty cycles, will have less than optimum IEA Auto-Phasing values (LINK). He also made the same statement as you, that you shouldn't inject fuel past the intake valve closing point.

And their math often puts it ending after the intake valve closes.

You're right, and it does so on my application too. Since a positive IEA value indicates the fuel injection event will end after Bottom Dead Center of the intake stroke, I don't see the benefit of doing that. At BDC of the intake stroke, my intake valve is nearly closed. So I don't I want or need any positive Injector End Angle values in my Auto-Phasing Table.

[S2H]

You almost never need positive values for Injector End Angle. (Unless you have a monster sized cam, then it can be useful. And by monster, I mean 280°+ duration at .050" lift.)

The big problem is that it centers it, which is the wrong way to do it. It should shoot for getting all the fuel into the cylinder roughly 10°-20° before the .050" values for the latest end of injection (and not try to center it like the EFI software currently does).

I've found on most vehicles, I end up usually closer to BDC at WOT, and have values somewhere in the -65° to -180° area at idle, usually on a race car. On vehicles that need a little help with the gas smell, I back it up even further at idle.

Heck, most factory ECUs try to spray the back of the CLOSED intake valve at idle to help with emissions.
They rely on the heat to partially boil the fuel into a vapor, to promote better combustion at idle.

In an ideal situation, you spray so that the fuel all goes into the cylinder, starting the injection so that it just starts to spray as the intake valve is opening, and ending somewhere near BDC and before the intake valve closes.
But not everybody had the right size injectors to do that. Most people have an injector that's too small and they are near 100% Injector Duty Cycle at WOT high RPM. When in reality, you really need to be in the 50-70-% range to get more ideal fueling.

You do have to take into consideration the distance away from the valve the injectors are. So the further away the injectors sit, the earlier you need to spray the injector.


Just to add to this, even though it's not really related to the original post questions:
Here's a video that shows end of injection: https://youtu.be/6kQGp-fHuFc
Their reference value is based on TDC Compression stroke = 0, and 360 = TDC Intake stroke.
You can see that they are trying to get all the fuel into the cylinder before it closes.

This is optimized for that particular engine. It does not mean that you can generically plug these values in any engine.
Some like it later, some like it earlier. It will vary with shape & design of the intake ports and the placement of the injectors.
The further away the injectors are, the earlier you have to setup the injection timing.

[Danny Cabral]

You almost never need positive values for Injector End Angle. (Unless you have a monster sized cam, then it can be useful. And by monster, I mean 280°+ duration at .050" lift.)

I've found on most vehicles, I end up usually closer to BDC at WOT, and have values somewhere in the -65° to -180° area at idle, usually on a race car.

This is exactly what I'm referring to in post #5. I don't want any positive Injector End Angle values, nor do I want to inject fuel beyond the intake valve closing point. A zero degree IEA value indicates the fuel injection event will end at Bottom Dead Center of the intake stroke, so that's just fine by me at WOT.

The big problem is that it centers it, which is the wrong way to do it. It should shoot for getting all the fuel into the cylinder roughly 10°-20° before the .050" values for the latest end of injection (and not try to center it like the EFI software currently does).

This is the Injector End Angle Auto-Phasing table aspect you brought to my attention, and thanks for doing so.

On vehicles that need a little help with the gas smell, I back it up even further at idle.
Heck, most factory ECUs try to spray the back of the CLOSED intake valve at idle to help with emissions.
They rely on the heat to partially boil the fuel into a vapor, to promote better combustion at idle.

Yes, I had already modified the idle area of my 16x16 Injector End Angle Auto-Phasing Table (LINK & LINK).

Here's a video that shows end of injection: https://youtu.be/6kQGp-fHuFc
Their reference value is based on TDC Compression stroke = 0, and 360 = TDC Intake stroke.
You can see that they are trying to get all the fuel into the cylinder before it closes.

Yes, I've seen that video before. In fact, I've posted it several times.

In an ideal situation, you spray so that the fuel all goes into the cylinder, starting the injection so that it just starts to spray as the intake valve is opening, and ending somewhere near BDC and before the intake valve closes.
But not everybody had the right size injectors to do that. Most people have an injector that's too small and they are near 100% Injector Duty Cycle at WOT high RPM. When in reality, you really need to be in the 50-70-% range to get more ideal fueling.

Yes, in order to optimize Injector End Angle tuning, larger fuel injectors are required to spray short injector pulse-width
durations (especially at higher RPM). This makes it possible to fit the fuel injection event in the programmed time frame.
http://www.kylesconverter.com/freque...er-millisecond (RPM To Degrees Per Millisecond Conversion)

HIGH IMPEDANCE INJECTORS — Most injectors can be divided into two major categories: high impedance 12 to 16 Ohms and low impedance 1.2 to 4.0 Ohms. The high impedance injectors are used with ECUs that are designed with saturation drivers. The advantage of using saturation drivers is that the currents running through the ECU circuits and the injectors are relatively low thus generating less heat. The disadvantage of saturation drivers is that the driver has a slower response time, which could affect the full utilization of such a system at very high engine RPM. LOW IMPEDANCE INJECTORS — The low impedance injectors are designed to be run with an ECU that employs peak & hold drivers (also called current sensing or current limiting drivers). The current ratio (peak to hold) is generally 4:1, and the most common drivers available are 4A peak/1A hold or 2A peak/0.5A hold. The peak current is generated to overcome the inertia of the closed valve and once the valve is open the driver cuts down to 1/4 of the peak current to hold the injector open until the end of the metering event. Low impedance injector designs are mostly used in high flow applications.

[VINCE]

For us street folks, will just setting the entire table to 0° be OK, and maybe something like -180° in the idle area, get us close enough for what were looking for?

[S2H]

Try it between -180° & -135° to start. (This represents 360° to 405° in a 720° 4 stroke cycle.)
Typically most street engines with mild cams in them, will end up somewhere in the 360-450 area (out of 720) at idle.
and increasing with more RPM (as air velocity goes up, you can spray it slightly later).

It's best to try to find where it idles the best (or cleanest, or the most stable).
And then you can test on the dyno how much to increase as RPM rises.
Though it's usually not a whole lot if your injectors are maxed out.
When you are above 70% duty cycle, it really doesn't matter too much where you put it.

And changing the Injector End Angle doesn't make any huge differences.
Sometimes it's only 1%-2% at best. At the 600 RWHP level, you'll probably only see 6-8 HP at the most.

But where it will help is with the low RPM, when Injector Duty Cycles are 25% or less.
Part throttle will feel peppier and more responsive when you get the injector end angle right.

[Danny Cabral]

Injector End Angle At Idle

There's two schools of thought concerning Injector End Angle at idle, and both injection timing strategies have been implemented by OEM ECUs. One is injecting fuel at a closed intake valve (ending injection event just before intake valve opens), which is documented in this LINK. Typically, this is around −180° to −210° IEA (Holley EFI). This improves fuel atomization & exhaust emissions (hot intake valve vaporization), and almost eliminates the raw fuel exhaust smell (due to not injecting fuel during the camshaft overlap period - LINK).

The other is injecting fuel shortly after the intake valve begins to open (injection event occurs after exhaust valve is fully closed). Typically, this is around −120° to −150° IEA (Holley EFI). This happens later, bypassing the entire camshaft overlap period (no raw fuel exhaust smell), but still avoids injecting fuel beyond the intake valve closing point. It aids in drawing the air/fuel mixture directly into the cylinder (ideal for tip-in acceleration & cruising speeds), and doesn't waste any fuel through the overlap period. Try it both ways, and see what the engine likes.

This post explains the Injector End Angle table that works very well for me: LINK.
http://forums.holley.com/showthread....0207#post80207 (Related IEA Forum Post)
https://forums.holley.com/showthread...126#post227126 (Injector End Angle V2.6 Excel Spreadsheet)

Originally Posted by Holley EFI Software Help Contents The IEA Phasing Table is a 16x16 table that dictates when the fuel injector closing event occurs. All Injector End Angle values are referenced from BDC (Bottom Dead Center) of the intake stroke. A zero degree value indicates the fuel injection event will end at BDC of the intake stroke. A positive degree value indicates the fuel injection event will end after BDC of the intake stroke. A negative degree value indicates the fuel injection event will end before BDC of the intake stroke.

[VINCE]

Thanks Scott & Danny. Interesting topic. Seems like my engine likes -180° in the idle area, so I'll leave it there. Not a tremendous difference from the base setting, but a little noticeable. My cam is 218°/223° and I'm getting around 19" in gear, so it's not wild. IDC for me approaches 70% at low boost, so I understand at that point, the table isn't doing much.

Last question - after messing with the IEA table, should Learn be turned back on, or the Base Fuel Table be smoothed/adjusted in anyway?

[Danny Cabral]

Last question - after messing with the IEA table, should Learn be turned back on, or the Base Fuel Table be smoothed/adjusted in anyway?

Turn Learn back on, and see if the IEA changes made a significant difference in fueling (Learn Table).

[S2H]

V4 Injector End Angle Auto-Phasing Table Explained

I just want to help explain the new V4 Injector End Angle Auto-Phasing table a little better, for those who are wondering what it is & how it works.

In previous versions of the software, you would enter Injector End Angle as a single value.
0° representing Bottom Dead Center of the Intake Stroke, and you could move it +/- 180°.

In Version 4, there is a new option to use a 16x16 table instead of just one value.
The table still works just like the single value does, except that you can program it based on RPM & manifold pressures.

In the Injector Phasing section, there's an auto calculation you can use based on your Cam Valve Events & Injector placement.
When you enter your camshaft specifications, and press the Recalculate button, it will populate the table with data.

The data that it puts in there is designed to center your injector firing time over the Intake Centerline of your camshaft specs.
It does this calculation based on your Base Fuel Table & Injector Size (to calculate Injector Pulse Width).

This picture shows what it is doing. The values in the table are only meant as a guideline,
and should be edited by the end user to better suit the needs of your engine.


Now with a basic understanding of how this function works, you can use this table to your advantage.

Over years of tuning, I've learned from some of the best in the business, and one thing I've learned, is that it's never a good
practice to spray the injector after the intake valve has closed. Unfortunately, using the auto calculation will create an end
of injection well past the intake valve closing event. You pretty much ALWAYS want the end of injection to happen before
the closing of the intake valve, ensuring you get all of the fuel into cylinder during the intake stroke. While the auto calculation
will not be ideal, you can use this auto calculation feature to help you find the end of injection that you desire.

So I made a quick example of how to setup the Injector End Angle 16x16 table to match what you want it to do, instead of
auto calculating and getting numbers that center it around ICL (Intake Centerline). I'm going to use just one flat number in
the table to make the math easy for this example. So for now, let's just say we want to have the actual end of injection to
happen at BDC or 0° Injector End Angle in the Holley EFI software in all of the cells in the table.

Start by saving your Global Folder file somewhere else, so if you mess it up, you still have a copy to go back to.
First thing you need to do, is zero out your Base Fuel Table. Don't worry, we will go back to your original values later.
You can either copy & paste your original table to another program like Excel, or we'll just close & reopen your file
later without saving any of the changes we make. But for now, don't worry too much about it. Just zero it out.
The reason we do this, is so that when the auto calculation does its thing, it's calculating based
on a zero millisecond injector pulse, which means it will point exactly at the theoretical ICL.


Next we need to setup the values on the Injector Phasing Table.
I'm using a file I have for an example, so I'll use the cam values for that file.
The injectors on this vehicle are approximately 5.5 inches from the valve (typical LS1).


Then click the Calculate button. It will populate the table based on your cam ICL and it will back calculate for the time it
takes the fuel to get from the injector to the valve. You'll notice, the higher the RPM, the further back the numbers go to
compensate, since the distance has stayed the same, but the valve events are happening quicker due to engine speed.
So it has to actually spray it sooner to get it there at the same point in the crank rotation.


Next, use the Offset to push the values around till the first row of cells reaches 0°.


This will now fire the injector so that the end of injection physically happens, so that all
the fuel gets to the cylinder at my desired example of BDC at all RPM and pressure values.

If you want the end of injection to happen at a different placement. Then simply offset this value by that amount.
If you want the cells at idle to be at -90°, then simply offset those cells by -90°.
If you want it to be at -45° around 3000 RPM, then just offset those cells by -45°.
If you have a wide variety of values you want for your end of injection angle, then you will either need to do them one
cell at a time, or get smart enough to use Excel to paste values into, and use the math functions to do the math for you.

Then simply ignore that page for the rest of the time. Do not ever hit Recalculate again, and
do not change any of the top section values ever again. They can all be ignored at this point.

Then you can go back to your original Base Fuel Table. You can either just right click and copy the values from the injector table,
then close the file and reopen your original file without saving, and then paste those values into the injector phasing table.
Or if you copied your Base Fuel Table to a program like Excel, you can simply copy & paste it back into the file you have open,
and then save the file.

Hopefully this helps some of you. if you don't understand this, re-read and just follow the directions.
I'm not going to try to explain it to everybody who can't figure out what I'm doing with this. This is obviously not for a beginner.

[Danny Cabral]

The higher you go in IDC, the less impact you will see from the end of injection timing.

Yep, that's why I just installed a set of larger fuel injectors, so I can take advantage of Injector End Angle timing at WOT too.

Nope, the auto calculator does not shoot for the end of injection.
The auto calculator shoots for the middle of the injector firing time, to be at the middle of the Intake centerline.

Exactly!

So I made a quick example of how to setup the Injector End Angle 16x16 table to match what you want it to do, instead of auto calculating and getting numbers that center it around ICL (Intake Centerline).

Thanks! I was actually working on something similar, but this is so much easier.

You will notice, the higher the rpm, the further back the numbers go to compensate, since the distance has stayed the same but the valve events are happening quicker due to engine speed. So it has to actually spray it sooner to get it there at the same point in the crank rotation.

Thanks for a great tutorial, and a visual calculation of the angular time it takes fuel to arrive at the intake valve.

Next, use the offset to push the values around till the first row of cells reaches 0°. This will now fire the injector so that the end of injection physically happens, so that all the fuel gets to the cylinder at my desired example of BDC at all RPM & pressure values.

With this method, I should be able to calculate what the IEA WOT value should be (top right corner cell value of 16x16 IEA table).

If you want the end of injection to happen at a different placement, then simply offset this value by that amount.
If you want the cells at idle to be at -90°, then simply offset those cells by -90°.
If you want it to be at -45° around 3000 RPM, then just offset those cells by -45°.

Yep, the modified idle values from post #7 & #10.

Then simply ignore that page for the rest of the time. Do not ever hit Recalculate again, and do not change any of the top section values ever again...they can all be ignored at this point.

Exactly!

[69cam]

Scott, you just might break the internet with that post. LOL. I have read it at least 5x over, and the YellowBullet forum post as well. I get the theory and understand your write-up. Very smart to say the least.

I do have a couple of questions if you or Danny wouldn't mind answering.

In the example pictured, it shows Holley's Auto Phasing aiming to split the injection cycle evenly before and after the ICL. That injection cycle is started & finished while the intake valve was open. Safe to assume there is reasoning for getting all the fueling done while the intake valve is on the lifting side and not the closing side?

I understand or think I do anyways, that the consensus is to get all of the fuel in before the intake valve closes. All of this is focusing on when to stop the fueling cycle. How do we know that at high RPM, longer pulse widths, that the start of the injection is not happening before the intake valve is opening? Anyway to find pulse width of a given injector based on fuel demand?

From purely a HEAVY gas smell at idle, I notice that several people have reported that an HEFI value from the -150° to -180° has improved their idle or richness smell. With that being the IEA point, it would seem like to me that the injection start point would be happening during the overlap period. Since the pulse width is lower at idle, it seems it would make more sense to have the IEA at around a -100° to -90°, to make sure the start of the injection misses the overlap? Thanks.