RE: diff swap question...

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

Hi Jeff-

	The Cover is the rear facing round cover with about a dozen or so
bolts. This has to be replaced so that the diff. will fit into the desired
space and provide the correct mounting for the 5 series. The mounting point
for the E28 chassis is different from the 325.  You will also have to swap
out the axle flanges as they too are different from 5 series to 3 series.

	As far as the engine noise and mileage goes I haven't noticed any
significant difference.  I realize approximately 19 MPG for everyday travel
and around  21-23 MPG for highway travel.  Noise really isn't effected too
much by the diff. Swap.  Yes the engine is running a bit faster with the
3.73 diff. (approx. 3250 @80 MPH) but not so much to worry much about.

Cheers-

Brad

- ------------------------------------------------------
Brad Herrin				______       Y  E  E  E
Corollary Inc.		    o/______\o     |__|__|__|	
2802 Kelvin		          (oo_00_oo)        |  |   	
Irvine, CA 92614-5826	    []o----o[]        H  A
Phone: 949.250.4040 X244	
Fax:   949.250.4043     '88' 535i (5 Speed/Stroked 3.8L)

Email: bradh@domain.elided <mailto:bradh@domain.elided>  or
bradley.t.herrin@domain.elided <mailto:bradley.t.herrin@domain.elided>  	

A WHOLLY-OWNED SUBSIDIARY OF INTEL CORPORATION		
			
- -------------------------------------------------------


		-----Original Message-----
		From:	Jeff Pharr [mailto:pharr@domain.elided]
		Sent:	Wednesday, December 09, 1998 12:36 PM
		To:	'bradley.t.herrin@domain.elided'
		Subject:	diff swap question...

		Brad,

		I have been following all of the recent diff swap posts with
great
		interest.  It looks like I will be forced to replace the
diff in my E28
		535i soon and am considering going with the 3.73.  Several
folks have
		indicated that it just bolts right in place of the old, but
that you
		have to use the cover from the original E28 diff.  What is
the cover?
		Is it the whole diff housing, or the round cover that faces
rearward, or
		something else?  I can't see why that rear cover would have
to be
		replaced, so I must be missing something here.

		Also, I do take some highway trips in my 535 so I am
concerned about the
		gas mileage / higher engine noise issues associated with
this swap.
		Would you still consider your E28 a nice highway cruiser?
Does it screw
		up all the OBC calculations?

		--Jeff
		'86 535i
		'89 325iX (maybe I could just borrow the 3.73 diff for a
while and my
		wife wouldn't notice...)

	
- ------------------------------------------------------------------------
		---------------

		Date: Wed, 9 Dec 1998 11:31:04 -0800 
		From: "Herrin, Bradley T" <bradley.t.herrin@domain.elided>
		Subject: RE:<all, E28?>  Diff Ratio Swap?

		Nathan wrote:

		Has anyone changed the stock diff ratio in either an E28
533 or 535 to
		the
		E30 325is (3.25 to 3.73)  By my calculations it should make
the car very
		quick
		and still "hopefully" pull about 125-130 mph.  Has anyone
else done this
		and
		has any comments, good or bad?  I have the chance to buy the
325 diff
		real
		cheap, and I want to do this to make my car quicker.  Thanks
ahead of
		time!

		Nathan
		85 535i

		- ------------------------------
		Nathan-

		I have done this to my '88' 535I with great success.   I
used the 3.73
		diff
		out of a 325iX.  You will need to swap the half shafts and
the cover
		from
		your original diff. But everthing else just bolts right up.
The
		acceleration
		is much better than before and you will notice a bit higher
revs at
		speed as
		the engine will be turning faster at a given road speed
(3250 @80MHP).
		I
		have also added a 3.8 liter stroker engine to the works
which makes for
		quite a quick ride.  I hope this helps.  I you have any
further
		questions,
		let me know.

		Cheers-

		Brad

------------------------------

End of bmw-digest V9 #670
*************************