2 different casdisks??? which to use

[260sexways]

(Bought as a backup since mine was modded)
http://i699.photobucket.com/albums/vv358/blake110491/IMG00453-20110628-0041.jpg
(Came on my ka ob2)
http://i699.photobucket.com/albums/vv358/blake110491/IMG00456-20110628-0044.jpg

[xpertsnowcarver]

The first CAS is the original OEM CAS disc.

The second is (what appears to be) an AEM 24 tooth CAS disc. These were designed for Nissan engines using the AEM Series 1 EMS that had high RPM CAS sync issues. It is possible to use this disc for other, fully-programmable EMSs that allow you to set the parameters for timing.

[260sexways]

Thats what i was thinking but i'm running the series 2 ems from aem. Thanks for the help