S13 Speedo Calibrated and Alternative tach fix..

[Bluefire]

Alright finally had some time to mess around with my car again and I finally got my tach and speedo reading correctly. This is in a S13 with S2 RB25 by the way

Speedo - For those with S13 speedos reading slow (roughly half) I found that the jdm speedo (180kmh) can be converted to mph and be calibrated accurately. I put the JDM speedo in, turned the pot all the way to the left, and now the speedo reads a touch too fast. maybe 10-15 mph off at around 70mph. So there is definitely enough range on the JDM speedo to calibrate it into 180mph speedo.

Tach - I gave up trying to figure out the right resisance needed to put the s13 tach into range. I don't have access to a function generator so its a big pain in the *** using the car to generate the signal.

Anyways I figure if the s14 tach can be adjusted to 6 cyl why not use the s14 tach and just switch face plate. So i pulled the needle off swapped the clear s13 bracket and face over the s14 tach and tested it out. Once calibrated against my power fc, I noticed one problem. The starting rpm was off. Basically at each 1k rpm, the tach was off by about 600 rpm.

The problem is the splining of the needle shaft. OK so say your at 1k rpm, when you install the needle back into the tach, it will either move to 1600 rpm or 400 rpm because the needle shaft only has like 6 splines. To remedy this I realized that only one end of the shaft is splined. The other end that sticks into the needle is not. So I used some pliers to hold the shaft while I adjusted the needle a bit. After a few adjustments I got it just right and now the tach reads perfectly.

In essence, you can use any 6 cyl tach or any other tach that can be calibrated to 6 cyl and simply swap out the face and readjust the needle.

In the coming week I will try to post a full write up with pictures.

-Bluefire