E3 4spd:What's your RPM at 60 or 70 mph?

[Buffarea]

My Bavaria was running 3000 at 70 mph which I thought was low, but recently I replaced the instrument cluster, and it now reads 3500 @ 70, and 3000 @ 60 mph.
Will someone take a drive in there 4 speed and help me dial this in?
Thanks

 

[bengal taiga]

My Bavaria was running 3000 at 70 mph which I thought was low, but recently I replaced the instrument cluster, and it now reads 3500 @ 70, and 3000 @ 60 mph.
Will someone take a drive in there 4 speed and help me dial this in?
Thanks

Your speedometer readings are a product of many factors, not the least of which is rear axle ratio and rear wheel tire diameter.

Assuming the unit is functioning correctly, the speedometer is calibrated to work with a specific rear axle ratio. (It has markings indicating the ratio on the back of the unit.) If your replacement speedometer was from a vehicle that had a different rear axle ratio, it will read differently.:? Effective gear ratios can be modified, to a lesser degree, by running taller or shorter than normal size rear wheel/tires. (To provide any accurate measurements, the comparison vehicle would have to have the same differential and rear tire size and have a matching speedometer.)

See:
http://www.rbracing-rsr.com/gearspeed.html
http://www.bimmerzone.com/speed.htm
http://ctny.audiworld.com/mark/s4/gears/gear_calc.html

hth

 

[Arde]

My Bavaria was running 3000 at 70 mph which I thought was low, but recently I replaced the instrument cluster, and it now reads 3500 @ 70, and 3000 @ 60 mph.
Will someone take a drive in there 4 speed and help me dial this in?
Thanks

The simple observation is that in the 1:1 gear (4th gear in this case) the speedometer and tachometer needles run parallel.

If there is a discrepancy the first suspect is the speedometer as it is mechanical and there is more than one variant for different differentials I hear. Tachometer is electronic and a rev of the engine is a rev of the engine regardless of other variables.