I have a 1987 RRC Turbo D with a 200 tdi conversion.

Former owner made the conversion so there are a few assumptions. The original rev counter never read the correct reading. At idle it reads 1000 when actual is 750-800 and at an actual of 2000 it reads 3000rpm. Actual rpm is taken by laser tachometer at the main pulley.

I have not taken the actual from the alternator pulley as im out of reflector tape for my laser tachometer.

Hoping I could find a quick answer online.

1. Does a turbo d rev counter different for a turbo d, or tdi. I was thinking it shouldn't be.
2. My 200tdi is a disco 200tdi. Alternator has a fresh rectifier and regulator.
3. Binacle voltage regulator? Temp sits at 1/3 at 180F coolant temp and fuel guage as far as i can tell reads correctly.

Any ideas?