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Thread: Ignition Timing with Small Cap HEI

  1. #1
    JOHNBOY Guest

    Default Ignition Timing with Small Cap HEI

    I'm planning on installing an Avenger system and utilizing the ECU timing control function with a small cap GM HEI distributor. The Avenger instructions state that the ignition timing must be synced with the ECU at "approximately 2000 RPM". Why at this speed? Also what is the best mechanical timing setting for the distributor at initial start-up? Thanks for any help you can provide.

  2. #2
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    A computer-controlled distributor needs to be 'physically synchronized' to the engine (at idle) and 'electronically synchronized' at higher RPM (Inductive Delay) due to the propagation delay inherent in the ignition module. You can temporarily "Enable Static Timing Set" (ECU Sync menu) to 30° to synchronize the ignition timing when revving the engine.

    http://www.holley.com/forums/showthr...&p=938#post938 (Initial Distributor Installation)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, 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.

  3. #3
    JOHNBOY Guest

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    Danny, thanks for the input. I'm currently running a stock vacuum advance distributor on the engine. Should I position the rotor on the new ECU controlled distributor at the same timing point for initial startup?

    Johnboy

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    Quote Originally Posted by JOHNBOY View Post
    Should I position the rotor on the new ECU controlled distributor at the same timing point for initial start up?
    No, do it as described in the link I posted. Computer-controlled distributors are installed with all the available timing advanced.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, 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.

  5. #5
    JOHNBOY Guest

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    Danny,
    Thanks for your help. Based on the information you have shared this my understanding on synchronizing timing with the Avenger: put the rotor on #1 post, set the crankshaft to 20 BTC, start the engine rev it to 2000rpm and adjust the rotor to match the timing on the handheld, lock it down and I'm done. Did I get it right?

    Johnboy

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    Quote Originally Posted by JOHNBOY View Post
    ...put the rotor on #1 post, set the crankshaft to 20 BTDC, start the engine rev it to 2000 RPM and adjust the rotor to match the timing on the handheld, lock it down and I'm done. Did I get it right?
    No, that's not what I said in that link above. Read it again.
    1) Lock the distributor hold-down bolt after synchronizing the timing at idle (turning distributor).
    2) Then momentarily rev the engine to 3000 RPM to adjust the Inductive Delay.

    You can temporarily "Enable Static Timing Set" (ECU Sync menu) to 30° for the entire synchronization process.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, 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.

  7. #7
    JOHNBOY Guest

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    Danny,

    I'm confused. The Avenger instructions say to lock down the distributor at "approximately 2000 RPM", you say to lock it down at idle. The Avenger is advertised as not needing a laptop, yet the link you reference requires a laptop to adjust the timing. Where can I get a step by step procedure on syncing the timing on the Avenger 550-400 to a GM small cap distributor using the handheld controller and not requiring a laptop?

    Johnboy

  8. #8
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    Read this similar forum thread:
    http://www.chevytalk.org/fusionbb/sh...rch/1/#2190226 (Similar Forum Thread)
    http://forums.holley.com/showthread....ing-Holley-EFI (Timing Synchronization)
    In other words, don't do it the way the Avenger & Terminator manuals instruct.
    It's not as accurate as the way I described in the timing synchronization Link.

    The Avenger/Terminator instructions will synchronize the timing to what Holley feels is "close enough" for Avenger/Terminator users.
    For exceptional timing accuracy, connect a laptop and do it right.
    That's what the "Enable Static Timing Set" and "Inductive Delay" is for.

    Excerpts from Holley EFI manual:
    Inductive Delay - Some ignition modules (specifically GM HEI and Ford TFI) may need this number
    altered if the commanded timing does not match the commanded timing as engine speed increases.
    If the timing starts to retard, this number can be increased in order for the timing to match.
    Enable Static Timing Set
    - Allows for a fixed timing to be entered. This is done when syncing ECU and engine timing.
    Last edited by Danny Cabral; 03-30-2012 at 06:12 AM.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, 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.

  9. #9
    JOHNBOY Guest

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    I saw no reference to connecting the Avenger to a laptop in the instructions. How do I find out how to connect and utilize it? Does it require support software? If so, does it come with the Avenger system? Thanks for the help.

    Johnboy

  10. #10
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    The Holley EFI software is available for free download on this website:
    http://www.holley.com/TechService/Li...#FuelInjection (Scroll down to "Holley HP & Dominator EFI Tuning Software".)

    You just need a typical mini USB cable from a digital camera/video game system, etc.
    It's a mini-USB on the ECU end, and a standard USB for the laptop end.
    I'm not using Holley's, but theirs is nice because it secures to the ECU case.
    I simply wire-tied my USB cable to the main harness (allowing a little slack), so it doesn't vibrate out.

    Holley's 558-409 USB cable:
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, 100HP progressive dry direct-port NOS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, 160A 3G alternator, Optima Red battery, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, 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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