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Thread: Sniper & A/C

  1. #1
    Join Date
    Jan 2018
    Location
    Holmen, WI
    Posts
    12

    Default Sniper & A/C

    I have not purchased SNIPER EFI yet, however, I'm well into reading the entire installation manual. I'm wondering how SNIPER works with A/C. Can it increase idle speed when A/C turns on? I believe I read of its ability to kill the A/C at WOT. I'm more interested in how it behaves with A/C in normal driving conditions. Would like to hear from those running SNIPER & A/C. Thanks! Shoebox

  2. #2
    Join Date
    Nov 2014
    Location
    Ont. Canada
    Posts
    1,349

    Default

    Download the Sniper EFI software and then you can see what it does.

  3. #3
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,403

    Default

    See the A/C IAC Kick function. Like the Terminator, HP & Dominator EFI, it's only a momentary increase in IAC.

    Are you looking for a momentary increase in IAC or a high idle function? The A/C "IAC Kick" function only produces a momentary increase in IAC, so the engine RPM doesn't dip down when the A/C is turned on (or in your case, electric fans). It works fine, but it does not increase & hold the idle RPM like a high idle function. Actually, the IAC Kick function is usually not necessary. It's typically a tuning issue with the Base Fuel Table. If you need a high idle function, it can be programmed in the EFI software Advanced ICF (1D Table, "Target Idle Speed Offset" Table Type, Switched Enable, A/C Kick Activation, Enabled) to use as a high idle switch.

    For more information about RPM dip/instability when electric fan(s) or A/C turns on: https://forums.holley.com/showthread...839#post211839 (Electric Cooling Fans Wiring Info)

    The Sniper EFI electric fan ground wires (pin C, light blue - Fan #1 & pin D, light green - Fan #2) trigger the relay coil − (terminal #85). Yes, terminal #85/Ground is the industry standard for good quality relays, with or without a diode. Sniper EFI instruction manual: LINK - page 17 & 50.
    Electric Fan #1/#2 relay terminals (ECU ground signal scenario):
    #85 - Ground signal from ECU Output.
    #86 - Fused +12V power to relay coil.
    #30 - Fused +12V power to relay contact.
    #87 - +12V power to electric fan.
    #87A - Not used in this application.
    Terminals #30 & #87 can be reversed.
    http://www.autoshop101.com/forms/hweb2.pdf (Understanding Relays)

    If your A/C compressor is ground activated, this works perfectly with the Sniper Input #1:
    See page 8, "10-Pin Connector": http://documents.holley.com/199r11193.pdf (Holley Sniper EFI Quick Start Manual)
    Converting A/C signal wire from +12V A/C compressor clutch wire to Sniper's negative A/C IAC Kick signal wire (Input #1) with a relay: https://forums.holley.com/showthread...699#post206699 (Sniper EFI A/C Compressor Signal Wiring Info)

    FYI: The A/C IAC Kick input must be used for the "Enable Fan #1 When A/C On" to function.
    Page 19, "Enable Fan #1 When A/C On": http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help Manual - EFI Software, Tuning & Datalogging)
    Then assign the A/C IAC Kick wire in the Sniper EFI software to Input #1.
    See page 8, "10-Pin Connector": http://documents.holley.com/199r11193.pdf (Holley Sniper EFI Quick Start Manual)

    If you're using the Holley EFI A/C Shutdown feature, it requires a relay for operation. It usually triggers a preexisting A/C WOT relay.
    http://forums.holley.com/showthread....9130#post49130 (Addition Information - Read Post #2 & #10)
    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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