Projectquick

I have always wondered how accurate the big autometer tachs are. My friend installed one in his 94 and it reads 3200 rpms while the stock tach only shows 2500 rpms. Every car I've seen with one always has two different numbers at the same time. Does this mean that the stock tachs are really inaccurate or are the autometer ones? If the stock ones can be as much as 700 rpms off, I can see that not ending well for some one.

Explosive

Did he do a motor swap ?

Projectquick

Nope, stock motor with a few things like an intake and exhaust. I know his is a little much but every car I've seen with one always has a discrepancy with the stock tach and the aftermarket one.

FuzzyDiceRule

mine isnt nearly that far off

did he accidentally clip or not clip one of the wire loops (the ones used to calibrate it to 8, 6, and 4 cyls)

mines is about 100 off, but not 700

Explosive

did he wire it up correctly ?

Projectquick

He had somebody do it so I'm assuming that they did it right. Fuzzy dice, you said yours is 100 off? Is it 100 low or high? I can get one with the shift light and all for 40 bucks, should I get it?

Explosive

For $40 I would, they aren't cheap new.

Projectquick

Is there a wiring diagram around here for one? I want to hook mine up with the easy disconnects so that at night when I park the car I can disconnect it so nobody sees it. As soon as you put one of those tachs in a mustang around here everybody assumes it's a rocket ship and next thing you know a week or two later somebody tries to steal it :/

PRO50SC

Mine is off about 2-300 rpms. I've never acually checked it against anything else. Could be a lil of either.

Projectquick

Is it worth the money? I plan on dropping in a carbed 351w this winter, will it have any problems working with that?