Thread: VNT Turbo and Performance Mods - 300 Tdi

Hello! In a first of all, I want to thank Jock personally and all aulro.com! I am from Ukraine (its not very big country between Russia and Poland).

I am very interested to install VNT Turbo on my 1996 Disco 300 TDI (no EGR, mechanical IP Bosch VE), but not able to buy complete kit. (About 2000$ + shipping + hi Ukrainian customs -quite expensive for me.)

So we have an idea buy used GT2256v from the MB Sprinter 416 2,7 OM612 Engine, Iveco Daily III 2.8 engine 8140.43K or BMW 330D 3.0 M57 engine,
rebuild it on local turbo service and install it by my self...

Originally Posted by Bush65

In the case of these particular VNT turbos, the actuator uses boost pressure - the majority of VNT turbos use vacuum or compressed air controlled by computer.

The question is - how to control VNT mechanism and non electronical fuel pump together, on a turbine from electronnicaly controlled car or van?

In case Allard kit, for example, we just put together hose from VNT actuator, from the compressor housing of a turbo and from head of Injection Pump?

Im very SORRY for my bad english

Originally Posted by airbagUA

Hello! In a first of all, I want to thank Jock personally and all aulro.com! I am from Ukraine (its not very big country between Russia and Poland).

I am very interested to install VNT Turbo on my 1996 Disco 300 TDI (no EGR, mechanical IP Bosch VE), but not able to buy complete kit. (About 2000$ + shipping + hi Ukrainian customs -quite expensive for me.)

So we have an idea buy used GT2256v from the MB Sprinter 416 2,7 OM612 Engine, Iveco Daily III 2.8 engine 8140.43K or BMW 330D 3.0 M57 engine,
rebuild it on local turbo service and install it by my self...



The question is - how to control VNT mechanism and non electronical fuel pump together, on a turbine from electronnicaly controlled car or van?

In case Allard kit, for example, we just put together hose from VNT actuator, from the compressor housing of a turbo and from head of Injection Pump?

Im very SORRY for my bad english

Sorry I don't know how your proposed VNT actuator is configured. The one Jock used and what was used on the 2.8 litre upgraded 300 Tdi from Brazil have a boost pressure actuator. Most VNT turbos from vehicles with engine computers have a vacuum actuator.

There is a method of controlling the vacuum actuator using a version of a "Dawes Valve" which was developed for the VW engine with VNT turbo. These are available from 3 Bar Racing. I'll see if I can find a link to web page where someone has detailed the method for a Nissan Patrol - or someone else may be able to find it quicker than me.

From memory a vacuum line is connected to the VNT actuator and boost pressure is tee'd into the vacuum line through the Dawes valve to modulate the vacuum signal - but my memory needs to be checked.

What ever you do, the pressure line to the boost compensator on the fuel injection pump has to be connected to some point where there is boost pressure. This could be the outlet from the turbo's compressor, or the inlet manifold. The compensator on the injection pump reduces or increases fuel injected depending on what the inlet manifold pressure is (ie. boost pressure).

Hope this is understandable and helps.

Thank you John! You're help a lot! This "Dawes valave" like a magic wand for me But while I do not quite understand how it works.
- Is it possible to buy only the vacuum actuator and install it on a pressure controlled turbine? Maybe you or anyone heard anything about it?
- Another question in both cases the pump is the same, or they too have the difference in the management of vacuum or pressure?

Thanks again and sorry for 156 questions!

You can always pull the vacuum actuator off and replace it with a pressure actuator.

I suspect that if you were to drill a hole and braze a tube on the other side of the diaphragm on the vacuum actuator you would then convert it to a pressure actuator. You would just have to watch out how much of a leak you would have where the controlling rod leaves the actuator canister.

But that's another problem! I found a topic on our forum dedicated to the identification of the actuator from the HS2.8 turbo. Link. It appears incredibly difficult to find ;(

All that we know about it: (thanks to Bush 65)

Originally Posted by Bush65

AFAIK, Garrett don't list any part numbers for any components against any of their VNT turbos.

Edit: the only markings on the boost actuator are "WAHLER" (looks like manufacturer of actuator), then at 180 deg from name is stamped "2/2" and at 270 deg from name is stamped "S 16/2".

Hope that helps.

Originally Posted by Bush65

...

There is a method of controlling the vacuum actuator using a version of a "Dawes Valve" which was developed for the VW engine with VNT turbo. These are available from 3 Bar Racing. I'll see if I can find a link to web page where someone has detailed the method for a Nissan Patrol - or someone else may be able to find it quicker than me.

From memory a vacuum line is connected to the VNT actuator and boost pressure is tee'd into the vacuum line through the Dawes valve to modulate the vacuum signal - but my memory needs to be checked.

...

Here is a link that shows the method I spoke of. If anything there is different to what I stated, please ignore what I have said as I was relying on my memory.

Originally Posted by airbagUA

Thank you John! You're help a lot! This "Dawes valave" like a magic wand for me But while I do not quite understand how it works.
- Is it possible to buy only the vacuum actuator and install it on a pressure controlled turbine? Maybe you or anyone heard anything about it?
- Another question in both cases the pump is the same, or they too have the difference in the management of vacuum or pressure?

Thanks again and sorry for 156 questions!

Nothing special about Dawes valves. They are a simple form of adjustable pressure relief valve. An internal spring holds a ball against a seat to prevent flow until the pressure rises enough to force the ball off its seat against the spring force. First used to prevent boost pressure to the actuator of normal waste gates on turbos. The version for VNT turbos is modified slightly and was originally developed to reduce the pressure spikes that were breaking shafts in the small VNT turbos on modified VW diesel engines.

I would expect the VNT turbo to have a vacuum actuator fitted when you buy it - most VNT turbos have a vacuum actuator, very rare to find one from another vehicle with a boost pressure actuator.

Your injection pump will work just the same and no change is required, other than the line to the boost compensator, should not be tee'd into the line to a vacuum actuator on a VNT turbo - the line must have boost pressure from the compressor outlet or inlet manifold.



In this diagram, blue line is vacuum, red is boost pressure.

You have a vacuum pump on your engine for the brake booster - tee into this but use a small orifice (damper on the diagram) to restrict the flow. To make the orifice, solder up the hole in a fitting then drill a very small hole (say 1mm or smaller).

The boost pressure is taken from the compressor. The boost pressure gauge is teed into the line, you could also tee into this line for the boost compensator on the injection pump.

Thanks! This picture just blow my mind ) I need time to think. I am very grateful for the help!