i was checking my RPMS from my Apexi AVC-R boost controller and found that my stock tach is about 50 rpm off @ idle
100 off @ 2000rpm

300 off # 3500-4000 rpm.
and so it goes as it gets higher...

i know that the rpm is not used to any boost control.

Just checking if anybody noticed it with any other tachs???

 

Stock tachs are always off versus aftermarket units of any sort. They are not that accurate after x number of years. This is true with most any car. IT is usually the stock tach that is off, not the aftermarket.

 

digital > analog