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Thread: Injector End Angle Auto-Phasing Table

  1. #1
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    Default Injector End Angle Auto-Phasing Table

    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)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  2. #2
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    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.
    -Scott
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  3. #3
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    Quote Originally Posted by S2H View Post
    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?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

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    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.
    -Scott
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  5. #5
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    Quote Originally Posted by S2H View Post
    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.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  6. #6
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    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 set up the injection timing.
    Last edited by S2H; 01-18-2016 at 09:43 PM.
    -Scott
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  7. #7
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    Quote Originally Posted by S2H View Post
    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.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  8. #8

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    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?
    96 MUSTANG/6.0 LQ9/S475 T4/HOLLEY HP EFI/TH400/3.27

  9. #9
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    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.
    Last edited by S2H; 01-22-2016 at 11:08 PM.
    -Scott
    Don't forget to check out progress on my Race Car:
    Project Blasphemy - 8.07 @ 171
    Low 8 Second Street Car

  10. #10
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    Default 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)

    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.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

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