4" Diesel Tachometer | 4K RPM | Classic Design

SKU: L4-TC7-LEG
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$234.10 USD
Tracks engine RPM in real time with support for alternator (R or W terminal), crank sensor, and magnetic pickup signals for broad diesel compatibility. Designed for clean integration across a wide range of diesel builds, from work trucks to custom swaps. Precision stepper motor delivers smooth, stable, and accurate readings.
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Order leaves our facility in about 2 Weeks

The Diesel Tachometer delivers clear, real-time RPM monitoring for diesel applications where dependable engine speed data matters. Designed to work with alternator signals (R or W terminal), crank sensor inputs, or magnetic pickup sensors, it integrates cleanly across a wide range of diesel builds and setups. A precision stepper motor keeps the needle smooth and steady, giving you accurate, easy-to-read RPM data without bounce or guesswork. Built with a durable housing and solid aluminum bezel, it’s made for real driving conditions and long-term use. Made in the USA and backed for life.

Track-Tested. USA-Built. Backed for Life.

Key Features:

  • Diesel Signal Compatibility — supports alternator (R/W), crank sensor, and magnetic pickup inputs
  • Accurate RPM Monitoring — real-time engine speed tracking under load
  • Flexible Installation — integrates cleanly across a wide range of diesel applications
  • Microprocessor-Driven — real-time accuracy
  • Stepper Motor Precision — smooth, accurate pointer
  • Weather-Resistant Build — built for street, track, and off-road
  • Made in the USA — backed by a lifetime warranty
Download Instructions

We recommend hooking up your diesel tachometer to either the alternator R or W terminal, crank sensor signal, or magnetic pulse sensor.

  1. To calibrate it, while hold the button down start the engine. The pointer to move to 1k rpm when in calibration
  2. Next, move the pointer to where your idle is by holding the button down. If you release and hold down again, it will move the other direction.
  3. Release the button, and after a few seconds the pointer will go to 0 and then current rpm.
  4. Your calibration is done! It is permanently stored in memory.
  5. This can be done multiple times if needed.
Built to last. Backed for life.
  • Lifetime warranty on internal circuit board electronics
  • 5-year coverage on sensors and wiring
  • Applies to gauges purchased since Jan. 1, 2006

Every Speedhut gauge includes a lifetime warranty* on the electronic circuit board inside the gauge case. It is the core of the gauge — the part responsible for the precision communication that delivers the accuracy and performance Speedhut is known for.

Sensors, wiring, and other external components are covered by an unlimited 5-year warranty.

This combined lifetime / 5-year warranty applies to the original purchaser.
*For your lifetime — as long as you own the gauge — we stand behind it.
Speedhut Inc warrants products to be free from defects in materials or workmanship. This warranty is limited to repair or replacement. Speedhut Inc is not responsible for incidental or consequential damages. Improper use, installation, or unauthorized modifications void this warranty.
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