voltmeter tach

Just a little observation from last night.

My oem KZ440 tach reads high after 4000 rpm.
So me being cheap, I got an 5" Autometer monster tach on ebay for $40.

I found out why it was cheap.
You have to use it on an 8 cylinder car.

There is someone on line that makes an adjustable adapter box.
You can make a 1 cylinder act like a 8 cylinder or 10 cylinder acting like a 1 cylinder (as well as 20 other ratios).

So, I use this and the gauge still doesn't work.
Turns out---the Autometer gauge works like a voltmeter.
1 volt =1000 rpm
2.6 volts=2600 rpm
10.2 volts=10,200 rpm

I needed one more adapter
It turns pulses into voltage.
$14 on amazon

The adapters worked well, but Monster tach was vibrating way tooooo much when riding.
It works well but I also needed something much much smaller.

I bought a tiny 3 wire digital voltmeter for $15.
The 3 wire voltmeter will read below 1 volt which will correspond to rpm below 1000.

I was looking at the digital Koso tachs before I figured this out.
They have some that start around $50, but I already have the tach adapters from the Autometer install.

My setup is around $90.
I was also going to use an analog voltmeter with a needle but they would be bigger and not immune to vibration.

widget man has the tach adapter
gkgoodcheapparts.com/products/bta-tach-adaptor

amazon board was a 0hz-500hz 0-10v (if you need more than 10,000rpm, you will need a higher voltage range here)
www.amazon.com/dp/B07TBVWTHH?ref=ppx_yo2ov_dt_b_fed_asin_title

I got the voltmeter from adafruit
www.adafruit.com/product/705?srsltid=Afm...m8palZD2s7a-DMYuIcnB



 

Did you rubber mount the new tach? 

Definitely did not rubber mount it..
Basically, I needed to verify my redline.. I was thinking i was at redline when I was at 6500rpm. 
So, it was a quick ugly mount.. 
It does look pretty obnoxious though!

 

WoW that's HUGE, ha.