Author Topic: LSD questions (Read 6201 times)

Cristian G in Oz · « **Reply #15 on:** September 25, 2007, 09:47:00 PM »

Hey Justin,

You make a compelling argument. If I could find a 3.73 LSD I might just change it, but at the moment the gearing is just great for me around town out here in Oz.

My highway driving would be greatly assisted by the better ratio though.

Thanks for you words of enlightenment. I don't get to do enough auto X (call them motokhana out here though).

Cristian

tjts1 · « **Reply #16 on:** September 25, 2007, 10:32:16 PM »

I think the trick is to keep both diffs around and swap them out quickly . I still have my 4.1 lsd in the back yard and I'll probably put it back in when the rainy/ski season rolls around. I was thinking about drilling 4 holes in the bottom of the trunk to make it easier for me to swap the diff. As much as i like my 3.64, its an open diff and i miss the LSD.

Patrick_Bateman · « **Reply #17 on:** September 28, 2007, 03:40:09 PM »

Quote from: Febi Guibo;34300

LSD was an option, 4.10 on the 318iS

So I know I have a 4.10 diff because that's what the tag on the diff says. How can I tell if it is an LSD? Are you saying that the 4.10 diff is the LSD option?

Wise Old Dog · « **Reply #18 on:** September 28, 2007, 04:10:21 PM »

If the tag has S4.10 stamped on it, it is an LSD. It came with an open 4.10 diff as standard.

Lukis · « **Reply #19 on:** September 28, 2007, 04:15:12 PM »

Should be a S on the plate, or on the house if it is a LSD (Limited Slip Diffrential)
LSD was an option on E30 318is, and 4.10 was standard.
If the diff is on the car you can lift it up so one wheel is in the air, put it in free and try to turn the weel.
If you can turn it lightly it is an open diff.
If you can`t turn it, or it is hard to turn.. congrat.. you got a LSD!!
You can also put a torque wrench(or what it is called) on the wheel bolt, and it should make 50nm before turning.
It is several people who think they have a 25 % LSD because they get 2 stripes in the asfalt, but you can get that with a open diff as well.

2002maniac · « **Reply #20 on:** September 28, 2007, 09:47:09 PM »

My 4.10 LSD started making all kinds of noise recently so i pulled it for a rebuild and put in a S3.73 that I had picked up from the junkyard for $35 with intentions of selling it on ebay. I have put 5 tanks of gas through the car since the swap and gas mileage has stayed EXACTLY THE SAME. I commute 100 miles round trip 3 days a week for school and I am simply amazed.

I can't really tell the difference in acceleration in 1st or 2nd but in 3rd on it feels a little sluggish. I even have to downshift to 4th to get up a grade on the freeway that was no problem in 5th with the 4.10

Moral of the story: stick with your 4.10

tjts1 · « **Reply #21 on:** September 28, 2007, 10:09:11 PM »

This is an LSD.

D. Clay · « **Reply #22 on:** September 28, 2007, 10:14:44 PM »

Link to a pretty basic gear program for fixed ratio transmissions:
http://members.dodo.com.au/~wawawa/
You can change the differential ratio and see MPH/RPM change. The problem with swapping differentials is that the old one could be perfect for the next track or AutoX layout.