I forgot about that air flap. Wire it open and see if that sorts out acceleration.

Sixto
87 300D

So it's done for me too!

I'm getting a steady 10 psi boost even at higher RPM (4000)!. I have installed a used actuator from an older A3 VW Turbodiesel.

I am taking the pressure line to the actuator from the intake manifold.

I do seem to have a slight issue with an intermittent loss of power under some conditions (but I have only driven for 30km so far, with icy rain!!!). I'm possibly having an issue with the ALDA, I expect it's full of oil and crude, so I'll drive it a bit, see how it goes and will later on remove the intake flap, EGR and clean intake manifold, then do ALDA and reassemble.

Thanks to gsxr for this thread, it was really helpfull.

Bye,

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BigBen

'98 E300 Turbodiesel 244 000km
RIP '92 300D 2,5 Turbo 632 859,4km due to engine failure

I agree, thanks GSXR, I'd be boostless without you. That's not a euphemism, just a fact!

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1983 240D Silver/Blue "Sadie", unknown miles. 100k miles on WVO single tank, converted to 2 tank about 10k miles ago, FPHE, Injector Heaters, Aux Fuel pump. Alcohol/Water injection. Frantz oil bypass filter
1992 300D 2.5 Turbo Green/Tan "Jade" 267K miles Stock.
1992 300D 2.5 tan/tan "Rocky" on 2 tank WVO. Pressure actuated Turbo "rat's nest" surgery completed. 197k miles

Note in post 8 -

Wastegate actuator swap for OM602.962?

... that gsxr tapped the compressor outlet for a wastegate actuator boost signal. You want the wastegate to respond as quickly as possible so this setup is ideal. Tapping off the ALDA signal line is... uhh... unideal.

Forced Induction, help me out here.

Sixto
87 300D

I totally agree, it's just a little more complicated to taped like gsxr did. But it is easy to understand it can be better.

Doing it as I did, on the other hand, was extremely easy.

When I have some more time and warmer weather, I'll surely do this like gsxr.

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BigBen

'98 E300 Turbodiesel 244 000km
RIP '92 300D 2,5 Turbo 632 859,4km due to engine failure

I forget how the 602 is laid out but I think you can replace the EGR valve with a plate with a fitting for a wastegate boost signal or tap the pipe that houses the butterfly valve. That'll be much easier than removing the turbo for drilling or drilling while hoping to bits fall into the compressor.

Sixto
87 300D

Air pressure isn't much different than any other hydraulic system, pressure will be about the same anywhere in the manifold. Using the slow moving, low turbulence air from the intake manifold will actually result in a bit more stable pressure curve.

The worst thing using the ALDA line will do is add a fraction of a second lag (boost spike) from the added hose length, restrictive angles and smaller hose diameter of the banjo fitting.

There is an M10x1.5 test port on the manifold that would be perfect instead of using the ALDA. Good luck finding a metric threaded hose barb in the USA though.

I used the test port and was able to get the correct fitting from ATP when i picked up the wastegate. Using this port, there is still a bit of lag. I think its because the boost signal is coming from so far down stream from the WG. Not sure if im gonna tap something closer to the WG. Or maybe use a boost controller.

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VegStew
1983 300SD 70,000 WVO Powered miles
1990 300D In driveway with Head Off - Cracked

This is truly a great educational thread.

Question: isn't the wastegate closed (boosting) until the pressure from the manifold builds enough to counteract the actuator spring (opening the wastegate and reducing boost)? If so, how would getting the reference pressure from the test port (manifold) result in turbo lag? If it takes slightly more time for the pressure to build in the manifold (as opposed to turbo discharge), wouldn't the only effect be to keep the wastegate closed slightly longer (hence no effect on the boost lag time)?

Also, does anyone know the distance between the centers of the mounting studs on the actuator, the length of the actuator rod, and the actuator rod diameter? I want to do this project, but my MB is an everyday car, I'd like to avoid removing the stock actuator until I'm ready to replace it.

It wouldn't make a difference in lag, it will cause a short boost spike (pressure higher than the desired setting).

did you come up with a parts list for the upgrade you did on the turbo ,i am in need of the same job on my car , the finished set up looks very similar to the turbo set up on the 940 volvo turbo , do you some how remove the flap off the intake tube I do have a spare intake tube set up thanks for your post

is there a short term fix until i can get this done without hurting the car ,i do have a newly rebuilt turbo as well to change over

The only parts needed are the wastegate, and a fitting for the intake housing. I still have not found a wastegate that is a 100% direct fit, only the one shown below which requires modification (shortening the shaft, as described in the first page of this thread). Additional photos are at this link.

And no, there isn't any (safe) short-term fix... sorry!

Attached Thumbnails

 

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hey gsxr,

I'm fairly new to the obvious in depth world of diesel mercedes, and I'm thinking seriously about doing this modification to my 1993 300D 2.5 but I have some questions about the modification. What exactly is ATP, I figure its a parts dealer of some sort like Autozone or something? In the side by side view of the old actuator and the new one, you indicate that the new one is 10 mm too long, yet the ruler is positioned vertically, is that to indicate where its too long at? I know these are probably questions answered earlier, but this looks like an easy job, and I'm tired of the horrible shifting, and acceleration issues I'm currently dealing with. This post is amazing...even though I'm only beginning to understand all the knowledge being kicked around in it.

A few saved rounds, this ALDA thats mentioned, whats that, and where is the test port? I didn't see one in your pics, is that the hole thats drilled/tapped into the housing thats removed from the turbo?