LSD question and possibly a right result

[chaosss]

When to my mates the other day who run a breakers. While there they happened to mention they had just taken an LSD off a car.

Having just bought 8 tyres that morning money wasn't flowing as such but I offered £100 jokingly and they accepted so I couldn't refuse.

The diff seems nice and tight and so a deal was struck. Now I assumed it was a 3.91 LSD which will be going on my track car (318is).

However after picking it up I don't think it is. Turning the propshaft end of the diff it takes just over 4 turns for one wheel rotation. So it could be a 4.1LSD which would be a right result for me.

But are there any other ratios it could be (I believe it came off a 320).

Also where is the plate I can check the part number on? I have looked at it but can't see anything obvious stamped anywhere.

[Demlotcrew]

IF its off a 320i it can be 4.27 or 4.10. There is a tag which is attached to the back cover by a bolt, its very thin and about three inches long.

Andrew

[Dan318-is]

If its a 4.27 slipper your one lucky b*stard!

[jonbuoy]

Do both output flange's turn the same way?
If it's an LSD then they will both turn the same way and the tag will have the 'ratio' then an 'S' printed after. You will find the tag on the back of the diff

[Conan]

Could someone explain what the difference is between the differet diffs and which ones are best for what?

(as in some are good for speed, some for drifting etc..................)

[jonbuoy]

A low ratio diff ie; 3.25, 3.64, 3.73 are good for econemy(sp) at high speed.
A high ratio diff ie; 3.91, 4.10, 4.27 are good for accelleration and drifting
The higher the ratio, the quicker the wheel's will spin and you have more control over steering the arse end round corner's and roundabout's

Check this out for the correct diff for each engine;

Diff Ratio

[Conan]

So if you get a high diff does it make a significant diff to acceleration times etc? (In a 325 Sport)

But would you really notice on the motorway?

[Zayyan]

So if you get a high diff does it make a significant diff to acceleration times etc? (In a 325 Sport)

But would you really notice on the motorway?

Of course, to an extent. Obviously if you go too far 1st gear can become useless. And yes, you'll really notice it on the motorway. If you've ever driven a 4-pot E30 you'll know what I mean - economy is awful

[Conan]

If you've ever driven a 4-pot E30 you'll know what I mean - economy is awful

Never had the pleasure

So whats the accepted best all rounder diff then. The one which gives best of both worlds?

[Zayyan]

In a Sport? Gotta be the standard diff.

[Conan]

thats handy!

[jonbuoy]

So whats the accepted best all rounder diff then. The one which gives best of both worlds?

I'd say 3.91 LSD, all round favourite.

[Conan]

Which one did the sport come with? (Theres no sport on that E30.de table)

[Chaos]

Which one did the sport come with? (Theres no sport on that E30.de table)

3.64 in a phase one
and 3.91 in a phase 2

[chaosss]

cheers for the replies guys. Will check it out when I get home tonight