I have an issue where my tachometer is off the higher the rpms go... 93' Civic SI original cluster.

At idle, the dyno and the tach read consistent... All other gauges seem to be working properly as well. At 3k rpms on the dyno the tach is roughly 2700. At 5k rpms on the dyno the gauge is roughly 4600. As it gets higher say 7k on the dyno it can be over 500 rpms off.

My problem is I can not tell where my true rpm is at as I come close to my redline and it effects my shift point. When the car redlines at 8600 the gauges are in the high 7000s and it is hard to gauge exactly where I am at.

I want to know how to calibrate my tach without adding a new race tach or other aftermarket tach, as my interior is completely stock and I prefer to keep it that way. Can anyone help or give advice? Thanks

 

Get used to running an aftermarket tach then. These things are notoriously inaccurate up in the higher RPMs.

 

I have the same issue with mine, is ur car swapped?

 

Yes the car is swapped... If I run an aftermarket tach would I have the same issue with being off because it is wired in to the original tach??

 

I would highly recommend this http://teknotik.com/blog/stack-st813...-dash-display/ not as much as the tach it's self is a needle connected to a little motor that gets a signal from the tach(green wire) coming from the dizzy. the prob is the stock cluster mine is off a bit in my integra by 2-300 I can tell by the vtec crossover point if I "creep over it" it hits at about 5.4K but if i'm flooring it from 3K it hits at 5.7K or at least that's what the tach says it's set at 5.5K on paper(s300) but you can't always trust the cluster

 

I got a cheap sunco tach and it works perfect. Its what im using now. When I first got the car I was searching around and I came across an old thread with a guy that had our same problem. He fixed it by swapping out his cluster and using a gsr cluster.

 

The tach signal comes from igniter unit via the blue wire of the distributor plug. You might want to try swapping in a new igniter unit to see if it makes the rpm readings more accurate.