Holset VGT
 

I am thinkin about getting a Holset VGT Turbo for my 300SD but the only concern i have is the electronics. What actually controls the vains of the turbo? i am wondering how easily this can be fitted to my engine.

check the performance section and search.

The engine's computer. The actuator is a mini computer in itself that the engine's computer communicates back-n-forth with. Trying to use it would be very difficult even for somebody good with custom computers.

Not easy at all. Everything will have to be fabricated. Oil supply, exhaust manifold mount, intake manifold connection, intercooler, air filter, exhaust system, vane control etc.

There is also the problem that even the smallest VGT Holset currently makes (HE351VE) is much too large for your engine. You would have to pump out around 400hp just to make use of it's capabilities.

You would be much better off using Garrett's GT20, GT22, GT23, or GT25 range of VNT turbos.

ya that is what i have been looking into. i want to get a garrett vnt they are just harder to find. what do they use to control their actuator? is it all mechanical?

Older ones use a vacuum actuator. Newer ones use electronics similar to the Holset but much less "smart".

so would the actuator run off of your intake pressure or your vaccuum system. electronic wouldnt be very hard for me i work with commercial building controls that would easily be fitted to this sort of application.

You will need to use a combination of boost pressure and the vacuum signal to the transmission (simulated manifold vacuum) to control it.

so if i am looking to fab a turbo to my 300SD would you reccommend a gt2256v or the next largest size (i dont know the model number). they are so hard to find.

Based on ease of finding one I would look for a GT2056V from a Jeep Liberty or a GT2256V from a Sprinter.

I run the GT2056V on my car.

which of the 2 would you prefer? did you notice a significan increase in mileage with yours?

Yes, 3 mpg or so. Both turbos have the same turbine, but the 22 has a larger compressor. From what I have read from ForcedInduction they both seem to work well on the 617. I am very happy with the 2056 on my car. There is a CAD drawing of an adaptor flange to fit the 2056 on the stock exhaust manifold on the board here somewhere.

Other way around. GT is the series of turbo, 20/22/23/25 is the size of the turbine, 52/56/59/60 is the compressor wheel diameter in mm and V means VNT.

this is all good to know because i am wanting to go beyond properly maintaining my car i want to start actually making things better. i have pretty much done everything i can do to get my mileage up, including putting my alda back on. it is not as fun to drive but i am willing to make sacrifices.

That does not affect your mileage. That was basically the same as putting a block of wood under your throttle, you could have the same results by constraining your foot movement. Driving habit and engine/drivetrain maintenance play the biggest roles in economy.

ya but since i took my alda off my mileage went way down and i am extremely light on my throttle. I simulated the alda with my foot and never even took it past 3000 rpm. since i put it back on i am up over 25 MPG which is good for all the hills i have to pull.