RE: E28 diff swap

["Herrin, Bradley T" <bradley.t.herrin@xxxxxxxxx>]

Ken Wrote:

		Brad,
		I just read your post regarding diff swaps for E28's.  I
have an '87 535is,
		and am contemplating a change of diff's, either the 3.46 or
3.73.  I'm
		afraid the 3.73 might get to be a little too much for this
car, but on the
		other hand, I'd hate to do just a little and not enough, if
I'm going to go
		into this job.

		My mechanic seems to feel that the 3.46 will be all I will
want.  But then
		another mechanic on the list says he does these swaps for
customers all the
		time, and that he always goes with the 3.73 on these cars.

		Hmmm... Can you give me any insight into whether or not the
3.46 is
		'enough' of a bump for these cars?  I think I already know
your answer, as
		you have chosen the 3.73, but I'd like to hear your further
thoughts, if
		you have the time.

		Thanks in advance,
		Ken Mitchell
		Durham, NC
		



Ken-

Thanks for the email.   Now let's see.  If you think about what the actual
difference would be with the 3.46 diff. verses the 3.73 you are looking a
only a 6.7% difference verses a 14% change.  I found somebody here locally
who had the 3.46 diff. and really didn't notice much of a difference at all
which makes sense as it was only a 6% change.  The 3.73 diff. made a much
more easily recognizable difference.  Although it wasn't dramatic , you do
notice a slight RPM increase and not really much more noise at speed.  At 80
MPH the RPM seems to be around 3250 as opposed to 2800-2900.  I didn't mind
this at all and most importantly my wife didn't notice it as she drives the
car from time to time.  She did ask what I did to give the car a bit more
pickup though!!!!!

If I had to do it all over again,  I would stay with the 3.73 LSD.

I hope this helps.

Cheers-

Brad


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Brad Herrin				______       Y  E  E  E
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