Differential ratios--what does it mean?

[BENZ-LGB]

OK, what is the importance, or the significance, of different differential ratios?

For instance, in 1991 a W124 300CE had a rear axle ratio of 3.06:1.

The 300TE had a rear axle ratio of 2:87.1.

The 300SL had a rear axle ratio of 3.69.1.

What is the difference in performance? Acceleration? Top speed? Gas economy?

Thanks.

[softconsult]

Just do a google search using let's say "Automobile Differential"
You will get very complete answers with illustrations.

http://web.mit.edu/2.972/www/reports/differential/differential.html

Steve

[Peter Guenther]

It is pretty simple, the higher the ratio in the rear end, the faster the drive shaft will turn, the faster the engine will turn, the more gas it will burn. The other side of the equation is, you will have more torque at the rear wheels, faster accelleration, lower top speed?,

[mbdoc]

OF course differential ratios are dependant on engine performance & weight of car....ALSO a big factor is the transmission final ratio as well.

UNTIL 1990 MB only offered a 1/1 final transmission ratio in their auto transmissions. After 1997 all MB auto transmissions are overdrive units.

overdrive units allow for a Numerical righer ratio.

[Ferdman]

BENZ-LGB, with a 3.06 differential the driveshaft turns 3.06 times for each turn of the rear wheels. Higher number differentials produce more torque ... some hot rods had 4.11 differentials ... and lower top end speed. Conversely, lower number differentials produce less torque and higher top end speed.

[BENZ-LGB]

Originally Posted by Ferdman

BENZ-LGB, with a 3.06 differential the driveshaft turns 3.06 times for each turn of the rear wheels. Higher number differentials produce more torque ... some hot rods had 4.11 differentials ... and lower top end speed. Conversely, lower number differentials produce less torque and higher top end speed.

Fred:

Thank you for the info. That would explain the higher numbers for the 300CE and the 300SL.

Again, thanks.

[Rockman59]

Ferdman said: "some hot rods had 4.11 differentials"
_________________________________________________________________
The real street rods and 1/4 mile drag strip racers ran 4.56 or even 5.11 gears. Not as much top speed....but you sure get to the car's top end quickly. Downside is more engine wear per mile of driving, lower fuel economy (not that racers cared about that) and a noisy interior due to more engine and exhaust noise.