Author Topic: Switch my diffs. 4.10 to 3.73? (Read 2573 times)

doucy2 · « **on:** November 28, 2006, 06:24:57 PM »

Currently 4.10LSD
getting a parts car with a 3.73LSD

think I should swap them for better MPG, how much of a difference will I feel, and loss of gearing.

what do you guys think?

bmwman91 · « **Reply #1 on:** November 28, 2006, 06:28:59 PM »

You will see 9% less torque to the ground from the gearing. Since you are going from an LSD to an LSD there will not be an extra mileage hit...open diffs can get better mileage. Lol, wanna trade diffs?

Gunni · « **Reply #2 on:** November 28, 2006, 07:02:36 PM »

what?
going from LSD to LSD will not change mileage?
that doesn�t make any sense,
when driving in a straight line and turning under no torque the diff is in effect open, i.e the clutches are not locking or minimizing slipping,

torque to the ground? want to explain how that makes a diffrence in mileage and or performance?

a 3,73 vs. 4,1 will change rpm�s by 9% and thats the end of it,
thus giving longer gears and potentially better mileage

silverblades181 · « **Reply #3 on:** November 28, 2006, 08:02:01 PM »

I think you'll get a lazy M42 with a 3.73. If you want to lower the ratio, you should go with 3.91 imho.