I have the E300TD and when running at 80mph I'm running 3000RPM. The torque curve for the engine maxes out at about 1700. Could I get better fuel milage with a different final ratio? In Europe they run much higher speeds, how are they geared different to achieve this?

Thanks.

j_button:

It seems like you should not be red lining at 80MPH. Possibly someone has already placed an incorret differential in your car. What model year is it?

-Scott

It's not at the red-line. Red-line is 5000 or 5500 but rather I'm running about 3000 RPM. My goal is to run about 2400 at 80MPH maybe a little less, that would be about 2100 at 70MPH, I think it could pull that up hills.

It's a 1998 sorry forgot to include that.

j_button:

If it were mine, I would stay with what a team of M-B engineers felt was the best balance of power, torque and speed for varying driving conditions our cars see. If you decrease your rear end ratio, your launch acceleration will suffer and the tranny will be shifting at lower speeds. You will also need to modify or replace your speedometer and odometer to compensate for the difference.

-Scott