ken garchow

has anyone here thoughtof, or done, a differential gear change to a lower ratio? to give more around town grunt out of hole? are there other benz diffs that have a lower ratio that can be bolted in?

this is can be in bmw's as there is a lot of interchangability between 5 and 7 series cars, and the 6, 8 and 12 cyl engins. the diffs vary from 3.08 up to 4.27. switching to a lower raatio (larger number) can sure wake up a car.

thanks

blueSL

I think the SL600 had a different ratio compared to the others, but I really doubt it's worth the effort and considerable expense.

Black129

Just remember that when you put a taller rear end gear you will run higher rpm's on the highway. Also you will notice that you will wind the gear up faster which will give you lower rpm puch but it will top out sooner before the gear shift and feel like the car is giving up before the gear change.

RUCKDR

Ken,
I didn't see the year car you are referring to, but as BLASK129 said you will turn more RPM per gear. Not sure when the 129's went to a 5 speed auto (5th being .82:1, overdrive), but the 4 speed had a 1:1 ratio for 4th gear, and a 2.65 rear end ratio. I don't know if you are happy with, or don't care about the current gas mileage you are getting, you will care about it with a taller gear (it will get worse). You can go to the link below and insert gear ratios (transmission), and different rear end ratios to calculate RPM and speeds.
I personally would rather have a 5 speed, than a taller rear end ratio.


http://www.xse.com/leres/bin/gearrat...mference=81.40

Don