Project FD RX7 Restomod: Part 22 – DC Power Alternator, Raceonly Pulleys, FFE Hall Trigger Kit

FD3S 13B REW RX-7 engine DC Power 180A HP Alternator Raceonly Pulleys Full Function Engineering idler pulleyThe blue Raceonly billet pulleys and FFE Idler Pulley made the front of our engine look as good as the block itself.

FD3S RX-7 stock crank triggerNext, we tackled upgrading the factory crank trigger sensors.

FD3S RX-7 stock crank trigger sensorsThe factory engine control system uses dual variable reluctance (VR) magnetic sensors.  One sensor counts the 12-tooth crank position sensor while the other is used for top-dead-center (TDC) which is picked up by a single protruding arm on the outer edge of the trigger wheel.

Full Function Engineering Hall Trigger set vs stock FD3S RX-7 13B REWThe Full Function Engineering FD Trigger Hall features a nickel plated 36-1 tooth trigger wheel that delivers 3X the resolution of the stock trigger system, plus the reliability of a square-wave hall-effect sensor.  By comparison, the stock 12-tooth trigger wheel and dual VR sensors (right) are a far less accurate and older technology.

Hall effect sensors work at zero engine speed which can improve the startup of a rotary engine which typically crank at 250-300 rpm (4.2-5 revolutions per second).  They can tolerate larger gaps to the trigger wheel (5mm) and can operate upwards of 15,000rpm which makes it crucial to have more teeth on the trigger wheel like what FFE offers.

FD3S 13B REW FD RX-7 Full Function Engineering Hall SensorWe mounted the new 3-wire Hall-effect sensor in the FFE bracket with the supplied 18-8 stainless steel hardware.

8 comments

  1. The “no name” brand pulley is GReddy. One of the first under drive pulley sets to come out for the FD in the late 90s.

  2. Does the trigger wheel work with the Apexi power fc ecu? Been a while since I’ve worked on the car and have forgotten more than half when I was knee deep into the FD 10+ years ago.

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