Anybody recommend a specific tach to work with a rotary? Most allow to compensate for 4,6, or 8 cylinders. What setting do we put it on, or are there special rotary models out there?



Thanks,



Craig

we're 4 cylinder. stock tach is bigger than just about anything else

More like 6, arent we? Reads off the number of pulses in one rotation. Or does it have to do with spark plugs?

The number of sparks on the leading coils is the same as a 4 cylinder.

Doesnt each spark plug fire every other revolution, regardless of how many cylinders there are? https://www.nopistons.com/forums/pub...1047683561.gif Isnt that pretty much the definition of a 4 stroke?

a 4 cylinder engine fires a spark plug every 180degrees, just like a 2 rotor

My friend has one of those huge tachs in his car... He actually pulls it off though and it isn't ricerish at all. It's nicely mounted in a custom aluminum dash next to his steering wheel. He doesn't even have a speedo.

so what if youre running a non waste-spark ignition? i dont know anything about tachs, honestly.

i saw a race setup on an rx7 that had nice pro-comp (i _think_) auto meter gauges. the tach was smaller, but hell, you can see it just fine. nice big numbers.

More than anything if youre racing you just need the shift light.

i see the need for it for a certain applications, all factory tachs have a certain miscalibration to them, the higher in rpm you go the worse it gets, they also lag behind what the actual rpm is. If you have an S4 turbo and want to spin it to 8500 or more, you're really only guessing as the tach only goes to 8k, ya know?

Only in real racing do you need an accurate tach.

Most of the stock FC tachs are within 500RPM of actual, so this is not a big deal (for me).

If you want to, you can actually adjust the stock tach for better accuracy.

I see no need to replace the large stock unit that's in the middle of the instrument cluster.

I use what precious dash space for the 7+ other gauges I need to monitor. :(





-Ted

I just put a shift light in that I had from another car. It comes on about 200 rpm higher than the stock tach rpm. I don't pay much attention to it either so I'll probably take it out. If you're racing, after a while, you should be able to feel when you want to shift. I can tell when my car starts to fall off and I shift at that time.