Re: <E30> iX Rear Diff

["Alan Alfano" <Alan.Alfano@xxxxxxxx>]

>someone said the ix has the same rear end components as an E30.
>Is that true?

Bill,
I believe that I said that.
The subject was suspension (shocks and sway bars).
Sometimes things taken out of context do not work out, but in this case,
you are correct.

You mentioned that you have an E30. But you did not mention if you have a 4
or 6 cylinder.
Six cylinder (325) and 4 cylinder (318) E30 differentials are different and
will not interchange.
Housings and axle carriers are different. The sole exception is the E30 M3

>I'm looking for a new LSD for my E30 and I was wondering if I could use
one from an iX.

If you have a E30 6 cylinder, then you could use one of the two available
iX rear LSD differentials.
The iX rear diff housing is the same as regular 6 cyl E30. (part #s
verified on BMW Mobile Tradition CD).
The 5 speed iX rear LSD gear ratio is 3.91:1, the automatic 4.1:1.
See attached table of E30 stock/suggested ratios from Kormans website.
IMHO when changing diff ratios, it is important to consider highway/top end
speeds.
Too high a ratio could result in say 4000 rpm @ 70 mph, which would be a
bit too buzzy.

Note that iX owners have limited ratio selections, as the front and rear
diffs,
must be matched and the front diff is only available in 3.9:1 or 4.1:1
ratios. (the front diff is not LSD)

How to determine if you have/are looking at a LSD (limited slip
differential):
A LSD diff will have a large white "S" painted on top of it.
This can also be determined by turning one of the drive shafts, the other
should turn in the same direction if it is LSD.
If the other does not turn or turns in the other direction it is not LSD.

I have also included interchange options from other BMWs.

Conclusion: If you are looking for a 4.1:1 6 cyl LSD, then you could find
one from a:
E30 325iS, E30 325iX automatic, E30 M3.
A LSD was also available as an option on the standard E30 325.

Regards,
Alan Alfano
alan.alfano@domain.elided

BMW CCA #30492
iX Registry # 214

1988 BMW 325iX
1956 Austin-Healey 100M (2)

 BMW            Stock Gear Ratio       Sugg Ratio         Comment
 318i M10       3.64:1       3.91:1    4 cyl
 318iS (M42)    4.10:1       4.45:1    4 cyl
 325e, eS       2.93:1       3.25:1
 325i, iS, iC,  3.73:1       4.1:1
 325iX 5 Speed Trans         3.91:1    4.1:1              front and rear
 differentials
                                       4.1:1 from auto iX

Other Available Gear Ratios (318iS, 325e, eS, 325i, iS, iC)
2.79 ,3.15 ,3.46 ,3.64 ,3.91 ,4.27 ,4.45 ,4.75, 5.00, 5.28

Some sources for E30 6 cylinder diffs, I am not sure which is LSD,
but would guess that the iS and M5 variants are LSD.

 <E30> M3              4.1:1
 <E28> 5 series (1982-1988)        2.93:1       528e
                       3.15:1      524td
                       3.25:1      533i/iS
                       3.91:1      M5

===================================================================

>Date: Fri, 30 Oct 1998 10:08:09 -0500
>From: "Bill Trainor" <bill.trainor@domain.elided>
>Subject: RE: bmw-digest V9 #418
>
>Hi All
>I may be suffering from old age memory loss, but I think I remember a
while
>back on this digest that someone said the ix has the same rear end
>components as an E30. Is that true?
>I'm looking for a new lsd for my E30 and I was wondering if I could use
one from an ix.
>
>Thanks
>BT

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