Tachometer Calibration

Wav files for Tachometer calibration

from the column for your engine type choose an RPM somewhere near the middle RPMs

download the Wav file from that line in the table (right click and "save link as")

connect power and ground to the Tachometer

connect the red calibration lead clip to the tachometer input

connect the black calibration lead clip to the tachometer case

connect the other end of the cable to your laptop, computer, iPhone etc.

No other cables should be connected .. eg no connection to the car ignition system

With the tachometer in the orientation it will be in the car

Play the wav file at full volume, (if using windows media player, select "loop" to play the file continuously)

the tachometer should respond

adjust the tachometer to show the appropriate RPM in the table

 

Frequency	4 Cyl	5Cyl	6Cyl	8Cyl	10Cyl	12Cyl
	3000	2400	2000	1500	1200	1000
	6000	4800	4000	3000	2400	2000
	9000	7200	6000	4500	3600	3000
		9600	8000	6000	4800	4000
			10000	7500	6000	5000
				9000	7200	6000

 

For low revving engines a 50Hz tone may be useful;

Sometimes it is useful to use an alternating

and by special request !

The latest instructions for installing our RVI to RVC board can be found here

An FAQ with further useful information can be found here

 

If the tachometer does not respond to playing the wav file then you can try the following

increase the volume on the device playing the file

try with various combinations of bass and treble (tone)

try switching the red and black calibration wire connectors.

the sensitivity of every board is tested using a standard signal, so don't give up,

if you cannot get the tachometer to move, try another device,

A last resort is to disable a circuit protecting component on the board to increase the input amplitude. Details found here

 

Keep an eye out for the few tachometers that have the red and black wires switched..

the board will try to make the needle move the wrong way..

If this happens, you will need to switch the thin red and black wires

 

 

Videos of the Internal Conversion on YouTube
RVI to RVC 1 dismantling the tacho
RVI to RVC 2 fitting the circuit board
RVI to RVC 3 powering up the board
RVI to RVC 4 calibrating
RVI to RVC 5 alternative connections

 

the external resistor mentioned in the videos is no longer required

 

Checking calibration with an acoustic tachometer

For calibration on the car, a simple (although not always successful) alternative to a rolling road is to use a smartphone acoustic tachometer app.
We have tried two android apps (We have no affiliation or connection with these products) with varying degrees of success !