Speedhut 4" 8K Tachometer / 120 mph GPS Speedometer (R4-DS14-REV)
The Speedhut 4" 8K Tachometer / 120 mph GPS Speedometer (R4-DS14-REV) is a dual-function automotive gauge designed for high performance and reliability. It combines a precise tachometer for RPM monitoring with a GPS-based speedometer, offering accurate speed readings without the need for mechanical sensors. Ideal for custom builds, racing applications, and restorations, this gauge is built to deliver consistent performance, ease of installation, and a professional finish to any dashboard.
KEY FEATURES AND BENEFITS:
Dual functionality: Combines a tachometer (0–8,000 RPM) and GPS speedometer (0–120 MPH) in one unit
GPS-based speed accuracy: Eliminates the need for traditional speed sensors
Wide engine compatibility: Supports 1/2 to 6 pulses per revolution with tach signals over 1 volt
High-torque stepper motor: Ensures smooth and accurate pointer movement
Easy installation: Uses a spin-lock mounting ring and includes all necessary harnesses
Durable build: Solid billet aluminum bezel with weather-resistant construction
Made in the USA: Built to high manufacturing standards
Product type: Dual GPS Speedometer and Tachometer
Speedometer range: 0–120 MPH
Tachometer range: 0–8,000 RPM
Size: 4 inches (diameter)
Mounting hole size: 3.93 inches (100mm)
Signal compatibility: Accepts tach signals over 1V, 1/2 to 6 pulses per revolution
Power source: 12V required
Capacity: Not specified in grams/milliliters (electronic component)
Included items: 8 ft tach harness, 3 ft power/lighting harness, waterproof GPS antenna with 9.8 ft cable
Step 1: Mount the gauge in a 3.93" diameter hole on your dashboard using the spin-lock ring.
Step 2: Connect the power harness to a 12V switched ignition source and ground.
Step 3: Attach the tachometer signal wire to the appropriate signal output on your engine control system.
Step 4: Mount the GPS antenna in a location with a clear sky view (e.g., dashboard or roof).
Step 5: Connect the GPS antenna’s SMA connector to the gauge.
Step 6: Turn on your vehicle to power up the gauge. The speedometer will acquire a GPS signal automatically.
BENEFITS OF USING SPEEDHUT 4" 8K TACHOMETER / 120 MPH GPS SPEEDOMETER (R4-DS14-REV):
Time-saving setup: Installs easily with no need for traditional speed sensors
Universal compatibility: Works with a wide range of engines and ignition systems
Accurate performance: Reliable speed and RPM data regardless of gear ratios or tire size
Streamlined dashboard: Combines two essential gauges in one compact unit
Professional aesthetics: Sleek design enhances vehicle interiors
Integrated gauge design: Combines tach and GPS speed functions into a single device
Reliable GPS functionality: Offers accurate global speed tracking without calibration
Versatile engine support: Configurable for various pulse rates and signal types
Simple dashboard integration: Includes all wiring and mounting accessories
Built for longevity: Weather-resistant construction with high-quality materials
Product identification
- Brand: Speedhut
- Model / MPN: R4-DS14-REV




