SR tach calibration

[Second Shadow]

so I'm redoing my gauges, going with black face, white back light and red needles. I thinks it's gonna look pretty cool when done, but in order to make the needles red I pulled them, sanded off the white paint and painted them red(ie: lost my zero).

while I was at it I swapped a jdm SR tach in(9000rpm print is nice), and I'm worried about how it's reading. now I had a dohc ka so everything works fine, however I've got this bad vibe that maybe the tach isn't reading accurately. I set it to 800 rpm at idle, but it feels like my tach is reading lower than it should be, based on what the engine sounds like(I'm hoping I'm just crazy).

my speedo is reading fine (ghetto road side radar detector cal ftw), so I can use that to check the tach if I can get some speed-to-rpm in X gear values from people who know their setup is good. note: I kept the KA gear box(taller final drive). I don't need this thing to be dead on balls right now, just wanna make sure I'm not reading 5k rpm at 7k rpm, that kind of thing.

I tried to search for some values but all I got was 7500prm @ 70mph in 2nd(I'd really like some tamer values) and a crapload of "I have an sohc cluster" threads.

[homeslicej2]

Just put the car on jackstands today to do a complete brake swap and PS rack change. Otherwise, I would take her out and get you some gear to RPM to MPH values to baseline off of. What diff do you have? I have a J30 diff (like many 240 owners), so my RPM's read a bit lower than the stock open diff would.

[Second Shadow]

I'm not really sure what the PS/brake thing is hitting at. I have the stock open diff, and I'll go out and get some speed to rpm values for where it's set at as soon as I can. was just wondering what other people have theirs at.

[PyR0NiAk]

He's saying he can't do it RIGHT NOW for you because his car on jackstands so he can work on his ps/brakes..

[homeslicej2]

^this

[Second Shadow]

pyro, the moment I see what you wrote, and then re-read his reply, it makes perfect sense. at first I thought "why is he telling me to do that?" I think I'm gonna have to start IMing you before I post anything to make sure I know wtf I'm reading.

[PyR0NiAk]

pyro, the moment I see what you wrote, and then re-read his reply, it makes perfect sense. at first I thought "why is he telling me to do that?" I think I'm gonna have to start IMing you before I post anything to make sure I know wtf I'm reading.

I literally just LOLed...

[sidetrack9]

I have the same issue with my tach. My stock tach read at 850rpm n when i put in the sr tack it read at about 500rpm but drives fine. i never came around to figure out why but if anybody have a solution or a reason y that would help out a lot...thanks

[PyR0NiAk]

Did you pull the needle off? You might have put it back on in the wrong spot.

[Second Shadow]

I'm actually thinking about getting that data logger that plugs into the consult port, can't remember the name of it right now, but it was only like $150-200 I think. be nice to know for sure what the engine speed is.

also there's what looks like a potentiometer adjustment screw behind the gauge face on the tach, and I'm wondering if that's not a gain adjustment for the span. if it is, and if someone can make a gauge face that looks right....I think it's possible to have a more or less stock tach, in a stock cluster, that reads 10, maybe even 11k RPM. long shot but not impossible, and it be cool as hell.