Question about open to lsd swap.

[ontheground]

So i have an 89' 325i with a 4.10 open diff. I've been wanting to get an led for awhile now and a few have finally popped up on cl. Theres a 3.91 a 3.11 and a 4.10 and i was wondering if theres anything to gain by getting a diff other than the 4.1. My understanding off 4.10 is that the driveshaft has to rotate 4.1 times for the wheels to make one revolution. correct me if im wrong. so in my eyes getting the 3.11 or 3.91 would only rob me of some torque and let me drag out the gears a little longer. what should i do? Im tired of these one tire fires and i miss going sideways. Any advice would be appreciated.

[jlevie]

A lower ratio will decrease acceleration, but also reduce the engine speed in in given gear. If the car is a daily driver the sees a good bit of highway time, the drop in cruising rpm will yield a slight increase in fuel economy. A 3.73 or 3.93 would a good choice.

[bastianshaw]

sounds like your car is an auto, get the 410 LSD