Question about Tachometer

[Immeraufdemhund]

What does the tachometer measure? I know it measures Revolutions per minute. but of what? the flywheel? or something in the tranny? and to find out what the rps is do i just divide by 60?

[A20A1]

oops im on crack... divide sound right

it measures the crank speed I think.

[A20A1]

woo hoo. I get 125 RPS.

[smufguy]

i got 111111111122222222225555555555555 rrrrrrrrrrrrpppppppppsssssssssssszzzzzzzzzzzzzzzzz zzzzzzzzzzzzz

[shepherd79]

there are two types of electronic tachometers in cars, inductively coupled and direct coupled.

Direct connect electronic tachs have a direct electrical connection to the ignition circuit. These tachs use voltage signals in the ignition circuit to drive the tach.

The inductively coupled type of tach such as the Smiths electronic tachs of the 1960s uses a one turn loop of the ignition wire as the primary side of a transformer that couples the current pulses caused by the cars ignition circuit into the inside of the tach. The timing of those current pulses are used to drive the tach.

[Immeraufdemhund]

wha? I thought all our tachs were mechanical, not electric... plus that doesn't tell me much of what it really does.

[smufguy]

our car's tach is driven by the speedo cable for sure, cause thats the only shit i know plugs into the guage cluster, but also to note that there are fucking 7 different clips that connect on the back of the guage so it might be one of them that drives our tach, i dont know.

our tach is what brand? it says NS on it right? every damn honda has it? sure as hell my 4g has it.

[Immeraufdemhund]

negate (the) south..... hmm sounds like they have something against the southerners...... guess i can't say much, i'm a damned yankee

[startersgirl]

I think the tack is driven by the blue wires in the ignition coil.

[SQ is the SQUAD]

the tach measures the revulotinos per mintue of you crank, it is mainly used for 5spds to know when to shift so that they dont spin the crank too fast and throw a rod. autos come with them too because you can shift gears with an auto. the tach i belive is ran off a signal paulse from the ignition coil. on the tach you have the red line, you are not supposed to rev your car past the red line. rember high rpms are not good, rpm+ rins peoples motor

[2Fast_Fiero]

Tachometer.......connected to the speedo cable..........HA. Sorry!

[DarknessRS]

The tachometer is powered through the ignition coil like startersgirl said. The tach measures 100 rpms per every 200 pulses/min of the igniter unit.

Oh, and the speedo cable converts to an electric signal through the speed pulser, and that sends out 4 pulses for every revolution of the cable.

PS: NS stands for Nippon Seiki, a Japanese manufacturer that makes instrument clusters and other stuff.

[shepherd79]

the cable that goes to the gauge cluster is for speedometer and odometer.

[ACCORD EX]

tacho meter is connected to the ignition coil ! first i thought it was like the speedo cable !

MIKE

[Immeraufdemhund]

ok, so that's how it is measured. So what does it measure? does 1 revolution = 1 piston going from all the way up all the way around and back to that posistion again? or is it 1 revolution = 1 time around on the fly wheel?

[locknload68]

My understanding is that it measures how fast the flywheel is turning. Which would be the same as the speed of the crank since they are directly linked together.