A few comments. First, factory boost spec for the OM617.95x engine is 0.75-0.85 bar (IIRC), which is roughly 11-12psi. So you can safely turn up the boost to that range with NO worries. Second, the ALDA can only do so much. It mostly affects off-the-line (off-idle) power. Definitely try turning it up, BUT, if you don't see a power gain - turn it back down. A proper ALDA setting is turned down (lean) as much as possible without a noticeable power loss, then back up (rich) maybe 1/8 turn. The reason the ALDA can only do so much is because it is still limited internally by the full-load stop screw, inside the injection pump, behind the rear (governor) cover plate. So, to get more power with your new boost, you may need to open up the rear of the pump and richen the full-load screw a bit. Normally you never touch this but as pumps wear and become leaner, it can help out. Also if you add an intercooler, you'll get almost NONE of the benefit without turning up the full-load stop quite a bit (nobody has seemed to figure this out yet who actually installed an intercooler, which is sad.) Here is a small PDF file that shows the full load stop on an OM603 injection pump, which is different than the OM617, but the principle (and general location) is about the same:
http://www.meimann.com/docs/mercedes/Bosch_full_load.pdf
Anyway, on most OM617 cars, turning the boost up and fiddling with the ALDA gets power back to normal (13-14 seconds 0-60 for a 123.133, 1982-1985 300D sedan/coupe). Now if you want it FASTER than that, then you may need to fiddle with the full load stop, and/or intercool the engine - but turning up boost without intercooling is a great way to melt pistons. FYI, my 1984 runs right at 10.5psi boost. One day I pinched off the wastegate hose and did some 0-60 tests. Boost rose to about 15psi max (wow!), but there was ZERO power gain! None, nada, zip, zilch. 0-60 times were identical and there was no seat of the pants increase either. Adjusting the ALDA didn't do anything (I had already tuned it properly, but it had reached the internal limit.)
YMMV, etc... happy tweaking!
