The secondary turbo's are from v8 1ton diesel trucks they are used in a single configuration (very common in North America) the smaller primary will be an automotive one simaller sized to a pd150 turbo.
As for the VNT control I had posted this once b4 but here it is agian, its not mine, but a copy and paste from a site that i cant remeber the url to this portion is saved on my hard drive:
OIL SUPPLY
This turbo needs .3 gpm of oil @ 30 psi. minimum at full power. Any oil that you can use in the engine will work for the turbo. The oil drain uses one bolt and seals with an O ring. A flat flange with a gasket will also work. A .5 inch minimum inside diameter oil drain is recommended and must be within 30 degrees of vertical with no "sink traps" that will allow oil to puddle.
CARBON SEALS
The unit uses a carbon seal and therefore be used with a carburetor upstream in a draw through installation,although the Chrysler was fuel injected. Except for the VNT turbine, this unit is very similar to a standard Garrett T25. The compressor, bearings and seals are interchangeable with T25 turbos.
WATER CONNECTIONS
The water cooling is intended for passenger car applications where the turbo is bolted to a heavy cast manifold withlittle airflow and many miles of stop and go service. The water cooling is not needed on a race car that isn't driven daily. Likewise, the water is not needed when the turbo is mounted on headers that don't store heat like a casting can. The water fitting is designed to mate with a steel tube flare nut. These can be removed and a different adapter can be threaded directly into the pipe threads and in the housing. Remember that the water is only for cooling during shutdown, the oil cools the bearings when the engine is running. When the engine is shutdown the heatstored in the cast exhaust manifold "soaks back" into the turbo causing the water in the center housing to boil.
When this happens it is important that the bubble that forms can escape upwards causing water to flow in from below and allowing the cycle to repeat itself. The upper hose should connect to the engine at a higher point than thelower water connection. The water flow direction while the engine is running is not important. It is when the engine stops that the boiling occurs.
TEST INSTALLATION AND VNT CONTROL
To determine the ease of controlling the actuator and to discover any installation problems in general, the author installed a VNT25 on his sandrail (Dunebuggy). The engine is a 2 liter German Ford. To keep the installation assimple as possible, the turbo was mounted on an old Roto-Master cast iron manifold that was intended for a T04B. Drilling the bolt holes out to 9/16" allowed the turbine to fit 3 of the 4 bolt holes and sealed acceptably for the test. The turbo pressurized a Motorcraft 121 two barrel carb in a simple "blow through" configuration. The pressure side (small tube) of the VNT actuator was connected to the hose fitting in the compressor housing.
The results were instant boost and easy wheelstands in 1st and 2nd gear. The vanes were closed at idle and it was very quiet, even without a muffler. The VNT limited the boost to 12 psi without any further controls during thequick " around the block" bonzai runs. (This control point is a function of engine size and flow and may be different for your application.
The addition of paddle tires and some steep dunes, however, changed things. The engine was not fully loaded onsuch a light vehicle on flat pavement. On a steep incline the boost would rise to over 20 psi as the engine became fully loaded. The solution was to install a conventional wastegate to control boost when the flow range of the VNT was exceeded. This is recommended for all VNT applications.
BOOST CONTROLS
Chrysler did not need a wastegate because the backpressure of the stock exhaust limited turbine power. TheSandrail used a very low backpressure 2.5" exhaust system. The Sandrail installation simply ran a hose from the compressor housing to the pressure port of the actuator. Do not make the mistake of assuming that the larger 1/4" port is for pressure because it is the same size as the fittings on the compressor housing. The 1/4" port is for vacuum. The smaller 3/16" port is for pressure. Pressurizing the vacuum port forces the vanes closed at all times.
They will eventually plug up with carbon, causing the " potato in the tailpipe" effect. If your engine runs poorly or won't start again after your first test run, check the actuator hoses. The boost setting can be mechanically adjustedwithin a limited range by shortening the rod length. Make sure the diaphragm does not bottom out before reaching the full stroke. It can also be adjusted with an electronic adjustable boost control system that is designed to control a conventional wastegate.
A pressure regulator can also be used as a "boost over boost" control to raise the actuator pressure control point just as it is used on a wastegate. In a nutshell you run a controlled amount of boost to the "wrong" side of theactuator to cancel out part of the pressure on the boost side. Each psi put on the back of the diaphragm raises the boost setting by 1 psi and so on. This is plumbed by hooking up the actuator pressure port to a boost signal (i.e. the fitting on the compressor housing) directly as usual. Then hook up a second from the same boost signal to a pressure regulator and then to the vacuum side of the actuator. Setting the pressure regulator to 1 psi raises the boost `1 psi etc...
In an off road or race only application this simple system will suffice. As a minimum a " part throttle open" controlcan be easily achieved by connecting manifold vacuum through a check valve to the vacuum side ( big tube) of the actuator. The check valve is to block boost. To prevent any pressure from being trapped between the check valve and the actuator, a .030" bleed orifice to atmosphere should be used. This will open the nozzles when vacuum is present at idle and part throttle.
This has some important benefits:
1. It cycles the vanes every time the throttle is depressed which helps them stay free of carbon.
2. It prevents excessive EGR due to higher then normalbackpressure which affects idle quality.
3. It improves fuel economy by eliminating backpressure caused by the turbo.
4. It prevents part throttle boost which heats the intake air unnecessarily.
5. It provides a more linear feel to the throttle pedal position.
Hope this helps some
Topic: Torque (Read 4206 times)
