[Sagacious]

a friend of mine just recently sold me a sunpro supertach II. the green wire is to the dist, white is for illumination, red is positive and black is negative. i hooked it all up... and came to realize it's probably not setup for an 8 cylinder...and to my surprise it jumps to 8,000rpm and slowly keeps getting lower, so it's not working correctly. i know they work on 4-6-8 cylinders, but how do i change that setting? i assume it needs to be taken apart and have some pins changed around. ahh. someone help.

[crazy larry]

Unscrew the mounting bracket, the selector switch is on the back.

[4 Jaw Chuck]

These tachs are very slow to respond and lag terribly during full throttle excursions, I would be wary of trusting one to read correctly during full throttle blasts.

Don't ask me how I found this out, it was expensive. Assume it's a 1000 rpm slow in these circumstances because the engine will outrun the tach. A good quality Autometer Monster tach is a much safer bet for high performance use.



$114 is a bargain.

[rj57]

The Sun tachs I have all have an adjusting slot in the back you rotate for the engine you have.

True Autometer makes a great product, but I like the Sun tachs I have. And yes I'll admit I'm usually not out side stepping the clutch at 6,000rpm or higher.

[78 monte]

I use Sun tachs and I'cve had no problems with mine either.I'm not using it in a strip car or nothing but for a streeter its fine.
Yea the Autometers are better but also $100 more(thats a cam and lifter kit or an intake or something).

[crazy larry]

if your going to the strip, DO [size=+2]NOT BUY AN AUTOGAGE TACH[/SIZE] BY AUTO METER

AUTOMETER doesn't pay contingency money for their auto gage line. you got's to spend a little more for the contingency eligible stuff.

[4 Jaw Chuck]

Sorry Larry, I didn't know that?

Which tachs are contingency eligible?

The SunPro tachs are good enough for mild street use but just not of an "instrument" quality, on my RX7 12A the factory tach was better than the SunPro cheapies by a lot...like 2000 rpm out at 8500 rpm on the factory tach.

I don't trust them after seeing that.

The cheap monster tachs are decent, mechanism must be the same as the more expensive tachs...if you don't mind the loss of contingency cash they are accurate and responsive.

I think I let the kids play with the SunPro II I had, it's probably mounted to some jeep toycar around here somewhere.

[crazy larry]

heres a link to the auto meter site, it's flash, sorry.

click

for running anything but all out rpm racing, the Auto Gage is fine, as i think the sunpro is.....( not that i'm running a sunpro.....shhh)

Originally posted by 4 Jaw Chuck
These tachs are very slow to respond and lag terribly during full throttle excursions, I would be wary of trusting one to read correctly during full throttle blasts.

i've noticed that by the time my foot is out of the throttle, that the needle still hasn't peaked, and i wonder if it is peaking at all?

i really do not think my red line is 5200 rpm. it could be, but i think i'm winding just a little higher than that though.



as far as the contingency cash, you have to run two BIG auto meter stickers. at least their yellow!

[Sagacious]

i got the tach wired up, and moved the switch behind the bracket to "8" cylinder. at first the needle would point straight down when you start the car, then slowly work its way down to what seems to be the correct rpm. but as you drive the car the needle becomes very tempermental, showing like 5-6k rpm when im crusing at like 2k. the tach needle moves up and down with the blinkers as they blink, and also it responds to how high my stereo is. electrical interference? duh? find a different ground and 12v accessory line? probably common sense, i didnt think about sharing power/ground but i'd appreciate some input.

[Grusome Goat]

Well my opinion is forget the Sun and get an AutoMeter product. I had an AutoMeter 5" SportComp with shift light in my GTO till someone broke in it a couple of years ago, best tach I ever used. I have one of the Sun tachs in there right now with shift light that you can't see during the day and I don't think the thing has ever read right. Very slow to respond seems like it reads slow at higher rpm's. As soon as I can raise the money I'll have another AutoMeter product back in there even if it's an AutoGage. I happen to like to be blinded by a bright light when it's time for me to start grabbing gears.