FAST Crank Trigger

[Raymond_B]

Was looking at this and wondering why only a 4 tooth wheel? I understand it is for a 90 deg V-8, but the OEM wheels I see posted on this board have quite a few more teeth.

http://www.fuelairspark.com/fas/crank-t ... ancerhtml/

[old guy]

That unit is highly overpriced, much like everything that FAST sells. And the description is pure BS. Show me any OEM that is using a 4 tooth trigger wheel. With a 4 tooth wheel your park resolution is not that great.

[Matt Cramer]

Because FAST was not able to code an every tooth wheel decoder for their XFI. Not sure if this is a limitation on their processor or its firmware.

[ashford]

is it just me or is that a ford modular cam position sensor

[Six_Shooter]

Because on a V8 crank attached trigger wheel for ignition duties, 4 poles are all that is needed to coincide with the TDC events of each cylinder. If you look in the dizzy of many V8s, you will see 8 poles on the reluctor because the dizzy spins at half the speed of the crank.

These are used for simply ignition trigger duties, usually to ignition boxes, where there is still a dizzy involved distributing the spark to each cylinder. The crank trigger is simply to provide the TDC trigger event for the ignition box (or ECM) to know when a cylinder is at TDC and nothing more.

MSD also sells a very similar trigger wheel for the same purposes.