3.0 engine speed/tach readout

[Kurt.king870s]

So since I got a tach, i've kinda thought it idled high. It reads 1500 rpms, and always seems like it's running slower than what the tach says.

So i'd like some numbers on idle engine speed, and the rpms at any given speed, in a specific gear.

For example: idle speed is 1200 rpms. 3rd gear at 3000 rpms is 35 mph with 3.42 axle ratio.
I'd like some numbers like that to see if my tach is close, or if I need to buy a new one.

 

[RonD]

Doesn't sound right, warmed up manual trans would be 650/700, automatic in Park 750/800
Cold start 1,100-1,200

Use this calculator: http://www.crawlpedia.com/rpm_gear_calculator.htm

M5OD-R1 Manual trans uses these ratios: 3.72 / 2.20 / 1.50 / 1.00 / 0.79
3rd is 1.50

A4LD(4R44E) uses these:
1st = 2.47:1
2nd = 1.47:1
3rd = 1.00:1
4th = 0.75:1

 

[Kurt.king870s]

Thanks for that link. My tach is about 1,000 rpms off most of the time if that calculator is correct.

 

[RonD]

Is it a 3rd party tach?

Hooked to Coil "-" terminal

Set for V6