The other is a mixing pipe throttle plate. Wire it open after converting to a boost actuator.

Sixto
87 300D

Bob, if I recall correctly you were one of the ones getting pressure off the manifold ports. There was a bit of talk about distance to the turbo, etc. Has this worked okay for you? I really don't wanna pull the turbo and tap it if I can help it.

if you dont mind me chiming in ...
I did a 92 and took the supply off of the existing port on the intake... bottom line on distance... it is a fine point at best... that is to say manifold pressure is manifold pressure regardless of where you take it it will actuate the wastegate just the same... in my experience that is.

If you disable EGR you can fabricate a boost pressure signal source as/into a cover plate.

Sixto
87 300D

Yes, I ran it from the manifold, added a T-fitting and ran the hose. I posted some pictures. Wastegate actuator swap for OM602.962?

__________________
92 300D 2.5L OM602 OBK #59

Good to know - thanks for the feedback... helps to confirm that it will work as desired

Chris

Bob,

Yeah, that tee looked the easiest by far so I was going with your plan

I've got one of these jobs going on this week. Pretty straight forward.

It is interesting to note that the existing wastegate is inoperative. It will not hold vacuum much less close off like it is supposed to. With it inoperative the boost pressure never gets above 7 psi. With the wastegate locked in the closed position 14 psi is too easy.

__________________
Jim

I just got my new part today. The one question I have before cutting up and threading is - does the lever that the shaft connects to operate in reverse now that it's pressure instead of vacuum? In other words, in the original photos where the shaft is extended it's forcing the lever down or to the left depending on your perspective.. pushing it out I suppose you could say. Will it be pulling it in now when installed? or does the wg actuate the control level in the same way just with pressure instead? Hope that makes sense...

Yes Don and engatwork you are correct. With this modification boost is always on until it gets to approx 14 or where you adjust it and then it dumps.

sjh, I believe there is no overpressure switch on 92/93 models. Listed in job 09-0050

__________________
92 300D 2.5L OM602 OBK #59

Finished the conversion this afternoon and the car has all the boost it can use. The ALDA I'm running has been gutted which, when the turbo was not building boost, made the car smoke on full throttle acceleration from standing start. I've got another ALDA that I'm going to try in it either this afternoon or tomorrow just to see what difference it makes. Now, with the turbo building up to 14 psi boost the car runs good. Shifts are kinda hard so I may tweek it a little to see if I can smooth them out some.

__________________
Jim

Check to make sure you didn't knock loose any vac connections. I did that and had an awfully harsh 2-3 and 3-4 shift.

__________________
92 300D 2.5L OM602 OBK #59

After running it again with the boost gauge on it I think I will go back and add the spacer washers to the diaphragm attachment studs. When I installed it I had to compress the rod slightly to get it to fit on the wastegate actuator pin. It looks like this has the same effect as making the wastegate open a little later.

Without running an exhaust gas temperature indicator what boost pressure should you start to worry?

__________________
Jim

The old vacuum wastegate is extended by default (zero boost) and requires vacuum to pull in (max boost).

The new pressure wastegate is the opposite; it is retracted by default (full boost) and will extend under pressure to open the wastegate (zero boost).

If the new pressure wastegate cannot be adjusted such that it is holding the flap/lever FULLY CLOSED with no pressure applied, you must either cut the shaft, or find some other method to get the wastegate fully shut. Otherwise you'll never build full boost.

Speaking of which, my nephew's 1993 2.5T 5-speed had this conversion done a few years ago by the PO, and apparently the PO got the wrong wastegate... it would top out at 7psi. Clamping off the wastegate hose bumped it to ~15psi. We'll need to add a manual external boost controller to increase it to 15psi, which is easier than swapping the wastegate again....

__________________
Check out my website photos, documents, and movies!

That's old WG was the DEVIL to get to. Ugh..

I've got the new one on and didn't need to shorten it. I just followed a previous example by removing the nut, twisting it all the way in, and adding a couple lock washers.

I only created one complication. I don't know what you call it but there's a plastic hose/tube that leads from the rubber duct that comes from the air clean and goes up into the head next to the oil fill cap. That plastic took barely any stress and shattered. I've pulled it out of the top of the head where the gromet is. Now I gotta figure what that's called and where to get a part and whether I can drive it like it is in the interim.

Next weekend is EGR delete!

EDIT: There's a bit of oil in there too. A small amount of it puddled in the turbo.

__________________
I drive vegetarian