Hey im sure this has been asked before but im new to mercedes. I wanted to know what has to be done to add a turbo to my 74 4 cylinder diesel. Im just looking for a couple psi for more umph is all. Fabbing and all i can do. I was thinking of a k03s cause of the quick spool. Thanks again. Another question my car originally came from cali and i have it in colorado what can i do to possibly turn the fuel down for the high elevation.

You should already have an ADA(?) an automatic altitude compensating device on the IP. What engine do you have? 615 or 616? Turbo is not going to get you much more horsepower out of of that engine. If you search on here you'll find lots of opinions about turbocharging NA engines.
In my opinion, you simply need to face up to the fact that that engine is going to be a dog at Colorado altitudes. If you want to solve that problem, purchase an MB with the 617 turbo. You will find it will be like adding a second engine to your car.
(as an aside, I'm selling my 116 1979 300SD with a 617 turbo and I'm in Denver)

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Yeah, I believe the consensus is that, if you want more power, you should get the 617 turbo. It'll double your HP. Swapping engines is supposed to be far easier. The only advantage to adding a turbo over the engine swap is that you (presumably) already know the condition of your engine and you've already replaced some things and those will carry over. You can PM Graminal, he turbocharged his 616.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

X3 on motor replacement.
Have a look at JEBalles signature, it answers your question.
240D's have been improved power wise with a turbo. Every one talks of "only a few PSI", if you believe that, I suggest you go looking for the "tooth fairy". What starts as only a little boost slowly increases until failure. At the end of the day nothing replaces extra cubic inches. The 300D turbo (OM617) has been designed to be a turbo, it has all the necessary extras built into it to give reliable service. You are lucky that you have a car that the larger motor will fit very easily.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Your elevation means your first two or three psi of boost are just going to get your manifold pressure up to what it would be at sea level. That means you can run more boost (as shown on a gauge) than a lowlander. These threads should get you started:

http://www.peachparts.com//shopforum/showthread.php?t=272388

http://www.peachparts.com//shopforum/showthread.php?t=272728

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

Not sure a 617 turbo will fit that car easily. It's a 115. Don't the 115 616's have the oil filter housing in a different location than the 617 turbos.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Yes, the oil filter housing location is different. One style swaps into the other without modification, but not the other way around. I forget which style it is that fits both bodies.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

adding a turbo to that old engine will be very difficult. the throttle is what controls power on that engine (no linkage to it except start and stop) so it will have to be moved before the turbo to work, otherwise you can over speed the engine rpm.

a 617 turbo won't fit in a w115 without oil filter relocation.

I think the throttle-type IP could be made to work with forced induction. I believe the system currently works by comparing the pressure in the manifold to ambient. If you plumbed it up so that the "ambient" signal to the IP was boost before the throttle, the system would still work as intended.

__________________
Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

no. it uses a venturi to create a vacuum that pulls against the diaphragm in the ip to control fuel rate.