Hi All. I've read the other posts about this but while there was mention that the waste gate flapper (87 300 sdl sans TRAP OXIDIZER ) should be free moving with the turbo removed, how about the control rod with the turbo installed ? Should you at leaset be able to budge the rod a little by when gently prying with a screwdriver? Mine won't budge at all and manifold pressure as measured from ALDA nipple on the IM (phantom banjo bolt) is a whopping 6 psi @ 4000 rpm.

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1987 300SDL 216k
2003 F350 7.3L + Banks - 315k

The wastegate flapper won't move easily if it's attached to the wastegate actuator. Release the actuator rod (mind the circlip) if you want to test the flapper. You can use the vent side of a MityVac to generate about 15 psi which is enough to get the actuator to open the wastegate.

If the turbo is off the car, do a visual inspection of the wastegate to ensure the wastegate valve hasn't disintegrated and it's centered over the wastegate port when closed.

Sixto
87 300D

Well... Pulled enough apart to get a good look at the wast gate flapper / turbo :

1.) Flapper is free moving with linkage removed.
2.) ~12 psi applied to Waste gate actuator causes waste gate to open.
3.) Flapper closes fully when pressure removed; cycles when applied and released.
4.) Trubo is free spinning with no noticable axial or radial play.

5) Boost is ~6.5 psi (even checked my boost gauge tubing rig into cabin by applying pressure to entire line)

Can plugged CAT (MB replaced turbo and trap oxidizer around 100k ago) cause low boost? Logically it seems like it could... Can you run the car staight-piped long enough to see if boost gets better (and wake up any late sleeping neighbors) ?

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1987 300SDL 216k
2003 F350 7.3L + Banks - 315k

acquire the iron manifold and dump that trap ox,if it is clogged it will affect performance.

I'm sorry I probably wasn't clear in the last post. Do you mean the trapox on the bottom that mercedes retrofits? This car's turbo ate the original trap oxidizer and MB replaced the turbo and removed the original trap ox. I read somewhere on the forum that when they do that retrofit, they effectively put the trap ox farther down the exhuast stream. In that case, the iron manifold wouldn't change anything right?

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1987 300SDL 216k
2003 F350 7.3L + Banks - 315k

The replacement pipe bridging the exhaust manifold collector and turbo is a plain pipe. Nothing inside to clog.

If you can stand the noise, separate the downpipe from the turbo enough to relieve back pressure in the exhaust system. That should tell you if the oxidation catalyst just behind the transmission is clogged. It if is, rod it or replace it with a straight pipe.

Sixto
87 300D