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Product Summary

Universal Fit

  • Features a built-in Vehicle Speed Sensor (VSS) input source
  • Has a one wire ECM signals input source with a typical 5 volt square wave
  • Output can be selectable between either 8000 pulse per mile or 16000 pulse per mile
  • There are three different calibration options to fit your application
  • Input signal can range from 2000-200,000 pulses per mile

Key Specs

MFG. Part #SN74Z
BrandClassic Instruments

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Details

The Classic Instruments SN74Z has the following features when used as a speedometer interface:

  • Input Source Options
    • Three wire pulse signal generator input source
    • Built-in Vehicle Speed Sensor (VSS) input source
    • Most Tremec transmissions
    • Later model 700R4’s        
    • Typically a sine wave signal
    • Two wire pulse signal generator input source
    • Classic Instruments SN96 or SN95Typically a sine wave signal
    • One wire ECM signals input source
    • Typically a 5 volt square wave
  • Output
    • The output can be selectable between either 8000 pulse per mile or 16000 pulse per mile
    • Outputs a 12V square wave, 50% duty cycle
    • 8000 pulse per mile cruise control output
  • Additional Benefits
    • Three different calibration options:
      • Instant - drive 30 MPH and press the calibration button
      • Real-Time - press and the hold the calibration button to match the speedometer reading to the actual vehicle speed
      • Marked Mile - Drive a measured mile to calibrate the speedometer
    • Input signal can range from 2000-200,000 pulses per mile
    • State of the art signal averaging software that ensures smooth pointer operation, even in fluctuating signal conditions
    • Noise-reducing, filtered power output for powered speedometer signal generator

The SN74Z has the following features when used as a tachometer interface:

  • Input Source Options
    • High Voltage Coil signal input source
    • .5-6 pulses per revolution (1-12 cylinder engine)
    • Typically the negative side of an ignition coil
    • 5-12V Square Wave signal input source
    • 20%-50% duty cycle
    • Typically from an electronic ignition box or computer
    • Inductive Gear tooth sensor input source
    • Typically used in diesel applications where there is not an ignition system
    • The sensor can be mounted to the engine near the flywheel to sense the gear teeth as they rotate by
    • Can be used with 32-510 tooth flywheels, 32-510 pulses per revolution
  • Signal Output
    • 12V square wave, 50% duty cycle
    • 2, 3, or 4 pulses per revolution (4, 6, or 8 cylinder)
    • 3 preset flywheel tooth settings
    • 148 tooth – Chevy Duramax
    • 152 tooth – 5.9L Cummins
    • 155 tooth – 7.3L Ford Powerstroke

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Specifications

KEY SPECS
MFG. Part #SN74Z
BrandClassic Instruments