[W126 Coupe] Differential swap

[Sharan Bains]

Changed the differential on my 560SEC on Saturday morning.

My euro 560 had the 2.65 LSD and I decided to upgrade to a 2.82 in the 
interests of keeping highway refinement on that car. The 3.27 will be fitted 
to my 500SEC 'AMG' which will be the 'fun' car....

Plus my 500E has the 2.82 - and with the 560SEC having the AMG camshafts 
plus the 722.370 tranny from a '95 w140 S500 (with the link to the EZL for 
super instant shifts), the power output and driveline are virtually the 
same. The stock euro 560 output is 300bhp - add to that the AMG cams plus a 
free-flow exhaust and I have no doubt the power output is upto 330bhp. It 
certainly feels at least that (the diff was fitted over a month after the 
cams, so I have a direct feel for the power increase from the cams alone) - 
and the AMG cams do work superbly on the euro V8's. I am arranging for the 
560 to be put on a rolling road to get a power output which should give a 
reasonably good guide to what power increase the cams give. The tranny and 
2.82 diff maximise that power superbly.

The diff was an easy swap if not a right pain in the backside : the twelve 
10mm allen bolts holding the driveshafts to the diff were incredibly 
difficult to loosen. They come fitted from the factory with a decent grade 
of loctite.....and what an absolute nightmare. The three 19mm hex nuts on 
the prop shaft only took 40 seconds to undo. The twelve drive shaft bolts 
took 40 minutes !

Fitting up the new one was quick. As is the car now ! I simply cannot stop 
the rear 10J's spinning wildly...in any gear. It feels as quick as my 500E - 
although that car is a tad lighter and has more torque than my 560 (354 lbft 
vs 334 lbft), since the 500E M119 had revised intake valves to give 22 lb ft 
more torque than the standard M119. So no doubt the 500E would outrun my 560 
eventually,  but the standing dash to 60 would be VERY interesting. I drove 
both cars one after the other yesterday afternoon and it really feels to me 
as though the 560 is faster to that point.

But feeling and reality might be very different so I'm going to do some 0-60 
standing start times next weekend, once I have fitted the ratio module to 
correct the speedo, then I shall post up the times. I'll be doing the 500E 
0-60 times too.

Anyone suggest the best method of timing, number of runs etc ?


Carl Genberg told me I wold love the cams but love the diff even more. He 
was absolutely spot-on...as per usual. Thanks Carl ! Of course, my main 
objective with my 560SEC is refinement WITH performance.....I'm not looking 
for extreme performance (the 911 Turbo SE is there for that), just 
sit-up-and-take-notice normally aspirated power. And I know that's been 
achieved.....just need to quantify it with some numbers on power and 0-60 
runs.


talbir