Tachometer

[Intruder]

My tachometer reads approximately 48% high based upon the AC display verification.

[WVZR-1]

My tachometer reads approximately 48% high based upon the AC display verification.

Likely a '90 and it's not unusual and will likely continue to get worse. There's DIY repairs for recalibration and I'm sure someone will provide some links and maybe personal experiences. I understand the requirements but have never personally done a fix.

I discovered mine when actually trying to confirm a rear axle ratio that would have explained my tach variance but this was on a car that wasn't thought to be modified. I checked mine vs. a Tech1 scanner rather than the C68 display. Mine is repaired and correct but NOT by me.

[FU]

Easy way ? Take the lens off then gently pull the sweep off . Then read set it and push the sweep back on.

[Intruder]

Not sure what you mean by pulling the sweep.

[Intruder]

OK, I am guessing by "sweep" you are referring to the tach needle?

[LGAFF]

http://www.zr1.net/forum/showthread.php?t=17728&highlight=tach

[FU]

Sweep = Tach needle.

[Paul Workman]

Easy way ? Take the lens off then gently pull the sweep off . Then read set it and push the sweep back on.

He's kidding ;)!!

The error is a % (of rpm) error. In short, re-positioning the needle to read accurately only works at one rpm value. the same % error will result above or below that "set" rpm.

[secondchance]

He's kidding ;)!!

OR...if one were to pluck the needle and reset it to read correctly at idle, it would still read ~ 7000 x 1.48 minus 480 or 9380 rpm when actually at 7000 rpm!
!!:p

One way to get higher revving LT5!

[Intruder]

Yea. Who knew these LT5's would get up to 8,000 RPMs without hitting the rev limiter.

[Hog]

So you could rev the engine until you hit the rev limiter and then see what your tach was reading. Is the stock limiter 7200rpm?

[Intruder]

I really don't know what the stock rev limiter is set at. I will have to research that.