I don' think the Performance Indicator is something of any functional value.
I actually found the tach more useless because;
1) it's pretty slow to climb, and
2) even slower to recover, and
3) it's down from line of sight
4) in a dark hole, and
5) my eyes can't react fast enough either. and
6) the divisions are too small to be useful. Plus
7) there's no adjustable pointer, and
8) no shift-light, and
9) the beotch doesn't even have boobs.
So I took it out and installed a vacuum gauge in it's place. and So now, I can at least see when the engine comes up on the cam, and when I hit cruise rpm, and how much too small my carb is.
>But the most useful part is when I hook it up with the Vacuum advance, I can see what the Vcan sees, and after mapping that sweetheart, I can calculate exactly how much Cruise timing the engine is seeing. and from that, I can calculate about how far I'm gonna be able to drive on a gallon of gas, and from that, how far I can drive on a tankful. For me, that's a useful bit of knowledge when I'm 500 miles from home, out on the interstate.
>Plus, it knows when the powervalve is opening. and
>Even knows if the car is bucking the wind or has a tailwind, or if the car is ascending or descending. It even knows if I'm getting too close to the back of a hiway-tractor!
>If I plumb it to venturi-vacuum, it then knows exactly how far open the primary throttle valves are.
>If I plumb it to the exhaust system, it tells me if my pipes are too small or the muffler is too restrictive
>If I plumb it to the suction side of the fuel pump, I can tell if the pump is still pulling.
I mean, it's way more useful than the tach ever was.
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IMO
a tach has to be up on the dashpad, just a lil off the line of sight, so I can see the tiny shift-light come on at 7000, which is 200 rpm before the rev-limiter. and I set the pointer to some obscure and meaningless number, like cruise-rpm, to better my chances of not getting a speeding-ticket.
Plus it's a great place to mount a light for my overdrive and another for my hill-holder.
My Autometer tach, a tasteful 3.75/270* is on a bracket that slides left to right; so most of the time it is well off to the side, almost to the mirror. But on the weekend I start pulling it closer to line of sight, until the shift-lite gets annoying, lol..
