Haltech Driveshaft Split Collar 2.125″ / 53.98mm I.D. 8 Magnet Size: ID 2.125″ / 53.98mm

Precision Speed Sensing: Driveshaft Split Collar 2.125″ (8 Magnet)

In high-horsepower racing, the ability to accurately measure drivetrain speed is the secret to winning traction control strategies. The Haltech Driveshaft Split Collar with a 2.125″ (53.98mm) I.D. is a specialized trigger component for drivetrain-based speed sensing. Specifically sized for performance RWD driveshafts often used in LS-swap and Ford Barra builds, this collar features an 8-magnet trigger pattern. This high-pole count provides your standalone ECU integration with a high-resolution velocity signal, enabling the ECU to execute millisecond-perfect traction control and launch adjustments to maintain maximum acceleration.

Engineering Principles: Digital Velocity Feedback

A driveshaft speed signal is superior to wheel-based sensing because it directly reflects the rotational velocity of the power being sent to the tyres. This 8-magnet collar provides 8 digital pulses per driveshaft revolution, which the ECU interprets as ground speed. This Analogue-to-Digital interface ensures that the speed signal is immune to the low-speed jitter that affects inductive sensors. In a standalone ECU integration, this 2.125″ collar allows the tuner to calculate “True Slip” by comparing the driveshaft RPM to the engine RPM, a critical metric for fuel map calibration and clutch-slip protection in high-stakes drag racing.

Operational Benefits: Launch Consistency and Traction

The primary advantage of the Haltech Split Collar is the drastic improvement in Launch Control reliability. For builders of 1000+ HP 2JZ or LS engines, managing the “hit” off the line is everything. The 8-magnet resolution provides enough data points for the ECU to react before the car has moved more than a few inches. If the ECU detects an abnormal surge in driveshaft speed (tyre spin), it can instantly drop the duty cycle of the closed-loop boost control or retard Ignition Timing to keep the tyres planted. This deterministic control is the difference between a new personal best and a wasted pass. The billet aluminum split design also acts as a thermal barrier, keeping the magnets stable in high-friction drivetrain environments.

Fitment and Installation Protocol

This collar is designed to suit 2.125″ (53.98mm) driveshafts. The two-piece split design allows for easy harness integration as it can be clamped over the shaft without removing it from the car. The kit includes a 5/32 Allen Key for the mounting bolts. Proper concentricity is vital; any wobble in the collar will cause signal dropout at high RPM. The outer diameter is 86mm and the width is 9.54mm. It is compatible with Haltech Elite, Nexus, and Platinum series ECUs, provided they are configured for 8-magnet speed input. The magnets are high-strength neodymium to ensure a clean signal to the Hall-effect sensor, even with a larger air gap.

Technical Specifications

Summary & Includes

The Haltech 2.125″ Split Collar is the prerequisite for drivetrain-based slip management. Includes: 1 x Driveshaft Split Collar 2.125″ I.D. 8 Magnet and 1 x 5/32 Allen Key. Note: Verify your driveshaft diameter before purchase; common on performance RWD conversions.