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50 mm optical trigger wheel for Nissan SR20DET or KA24DE

50 mm Optical Trigger Wheel for Nissan SR20DET or KA24DE

5 out of 5 based on 2 customer ratings
(2 customer reviews )


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SKU: TW_SR20 Categories: , Brand:


Convert your Nissan CAS to a more MegaSquirt-friendly arrangement with our bolt-in optical shutter wheel! This one replaces the ring of four slits with a 24-1-1 wheel that behaves like a 12-1 crank trigger. Then we added an outside slot to provide a cam sync where the 360 degree slot ring works. So you can use just the inner ring to get a rapid sync-up, or use the outer slot to allow for sequential injection or coil-on-plug. Intended for use with MS1, MS2 or MS3.  (MS3 has experimental support for the stock CAS however). This is intended for use on the following Nissan motors, in alphabetical order:

  • GA16DE
  • KA24E (Note: Some KA24Es use a 54 mm trigger wheel; please check before ordering.)
  • KA24DE
  • SR20DE (Note: Some FWD applications used a 54 mm trigger wheel; please check before ordering.)
  • SR20DET (Note: Some FWD applications used a 54 mm trigger wheel; please check before ordering. All RWD versions are believed to be 50 mm.)

These may also direct fit to other Nissan, Mitsubishi, and Suzuki applications. Look for a 50 mm outer diameter with a D-shaped hole in the center. Does not fit most RBs, VG, or CA motors. Distributor equipped engines can gain extra resolution and more precise timing, while cars with coil on plug can now use MegaSquirt without having to add a crank trigger. Easy bolt-on installation, just take the cover off your CAS or distributor, remove the rotor on a distributor, and undo the big Philips screw in the middle. Once you’ve got that, it just drops in.

Click HERE link for how to use this trigger disc with MegaSquirt.

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2 reviews for 50 mm Optical Trigger Wheel for Nissan SR20DET or KA24DE

    Only logged in customers who have purchased this product may write a review.

    What are the benefits of using this trigger wheel over the stock trigger wheel?

    • When used with a MegaSquirt, this trigger wheel allows for more accurate timing (especially while starting) and cylinder identification. If you are having problems with the motor “kicking back” while cranking, this trigger wheel will fix them. It will also permit using sequential injection or distributorless ignition. Note that MS3 does not require this disc with an SR20DET as it has native support for the SR20DET pattern.

    Do I absolutely need this trigger wheel when installing MegaSquirt on one of these engines?

    • No. MegaSquirt can use the stock trigger wheel if you are running a distributor ignition and bank to bank fueling. Note that MS3 supports the stock SR20DET trigger pattern natively.

    Can I use this with a non-MegaSquirt ECU?

    • You will need to consult your ECU documentation or technical support to see if this pattern will work with your unit.

    Questions & Answers

    1. 0 votes

      Yes - we changed the thickness as the thinner discs were often a bit bowed. Usually not enough to affect operation once assembled, but we received a number of complaints.