Logger reading higher rpm than dash?

[LookDadNoBdyKit]

Today I hooked up a logger to my car and it was reading 700-750RPM higher than the RPM that was on the dashboard stock tach. What is the problem? Which is right? I noticed the same thing when I first installed my AFC and figured that it was just cause the cylinder setup was wrong. I bumped it up to 5-6 cylinders I believe to get the correct reading. Anyone have any insight to this problem?

 

[notractiongst]

Turn your AFC back to 4 cylinders stock tachs are innacurate
my AFC and logger say the same numbers while my dash tach says different

 

[spidy3]

this is kind of on topic. I have a similar prob. My stock tach and my scan tool read about the same rpm but my turbo timer reads about 500 rpm more. any insite on this? its hks, type 1 i think it is, black with 60' 1/4mile and all that other stuff.

thanks,

Dom

 

[JiggahMan]

My SAFC needed to be turned down to two cylinders or it wouldn't read above 3000..