oh the leaking seal, it is very unlikely to cause any real lose of boost, the volume is just to small, even having the line to the alda off and venting to the air would not cause a lose of boost. Think large volumes of air.

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1977 240D turbo

After getting all the lines cleaned and the boost gauge installed in my 85 300CD I'm seeing a max boost of 8 psi, with a regular boost of only 7. No smoke.

from reading here, It's my understanding that I too suffer from a weak waste gate spring. My boost gauge is tied into the hard line from the banjo bolt also using a Tee.

I have not checked the ALDA yet or done any adjustment to it.

I'm planning on getting out there today and playing with it some more and doing the spring adjustment.

turns out I have the KKK turbo... So I just finished increasing the boost and doing some testing.

Now the boost is around 17 but I saw it hit 19 for a second. I held it at full boost and the over boost protection kicked in at 16 and dumped the pressure... Like it should... So good there.

Now, I need to work on that Alda.. I'm still debating if I should remove it or just adjust it.

by the way the oil separater came, and is now on the car, thanks

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1977 240D turbo

Excellent! I'm glad that parts of my 240D lives on in others 240D's.

I got the wastegate tools made but haven't tried them out yet. Hope they work.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I got a hold of a junk Garrett turbo from a 617 with a seized turbine (been sitting out in the elements) and played with getting the wastgate cover off. The spring was corroded in by the oxidized aluminum groove that it sits in. After a lot of scraping and with the help of penetrating oil, I got the spring off. I then tried getting the spring and cover back on and have not been successful yet. Maybe I'm just clumsy but this job seems to be a royal PITA do do in situ if I am having problems on the bench.

I am going to try a manual boost controller before trying anything else. I think my adjustable fuel pressure relief valve should work just fine.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I made a MBC from an old (weak) fuel pressure relief valve, a 3/8 brass tee, a 1 " L 3/8 hose and some clamps. It tested at 12 psi opening pressure w the cap all the way in (spring fully compressed). By loosening the cap till it almost falls off (spring least compressed) pressure is 5 psi.

I am still getting max 9 psi boost (with the MBC valve cap all the way out @5 psi opening pressure). The boost comes on earlier with throttle input but max boost remains the same, There is a definite improvement how it accelerates. Should I shorten the spring in the MBC to get a lower opening pressure than 5 psi?

What should I do next to get it to 12 psi boost? What will that extra 4 psi give me in performance?


.temporary plastic bag & twist tie to catch the parts if the cap comes off

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

deffinitly get it up to 12 lbs <- you'll get that

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1996 s10 zr2 with a 6.5 turbo diesel
1996 c2500 suburban with a 6.5 turbo diesel
1981 300sd with a turbo 617
Monte carlo figure 8 car

Lets look at basics, generally speaking more fuel will give more boost,less fuel less boost. So boost is limited by two things fuel, and wastegate. Assuming your manuel boost controller is keeping the wastegate closed, then there is a lack of fuel. If I were working on this the next step I would take to install a fuel pressure gauge, and see if it is at least up to specs. Think around 18- 20 psi. If not get it up, and see what improvement you get. next remove alda at least for now. If you get into ip adjustments later you may want it back on. But now is not the time to get into ip adjustments. If this does not work then I would really expect that the wastegete is dumping, and getting it working right will be required. I have a spare for the garrett. I'll look and see what condition it is in.

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1977 240D turbo

Or the turbo could be unbalanced and not spin up as easily... though I'd imagine you'd hear that.

So apparently you've already chosen his intercooler, Lance.

Funny though, because I see most of these guys who are adapting and installing used/junkyard-find turbos, also adapt and install used/junkyard-find intercoolers (ex: Saab) and aren't necessarily getting optimum cooling nor optimum pressure drops, even finding optimum locations for airflow nor plumbing, ... thus my comment that it's a pretty big assumption.

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Gone to the dark side

- Jeff

Pardon me All:
Where does the intercooler go? Before or after turbo? Thanks

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1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

There is no intercooler on the 617. If you want to add one, it goes AFTER the turbo.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

An intercooler goes after the turbo, between the turbo and the engine's intake manifold to cool the compressed-air charge.

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Gone to the dark side

- Jeff

That's what I meant to say.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked