Turbo installation help!!

[motovelo]

Finally after two days of swearing and knuckle skimming not to mention getting ****ed wet through by this great June weather we're currently enjoying , I've managed to remove the turbo unit from my 412D Sprinter (brass manifold nuts are a nightmare to remove)! My question is this, I've bought a service exchange turbo unit which on the bench alongside the original is identical in every way except for one thing. The original has some sort of vacuum driven valve where there is a little rubber hose which goes back into the main turbo housing (presumably the pressure of the turbo spinning operates the vacuum which in turn opens the valve in the exhaust side of the turbo unit), on the new one the vaccum unit is visibly identical except it simply has a connector for the rubber pipe to connect to but it does not seem to have the matching connector on the turbo housing? I hope this makes sense so far?? Obviously the vaccum needs some sort of feed to operate it and my question is where would I connect this to or what would happen if I just leave it as it is i.e. don't connect it to anything?

 

[Uncle Benz]

You are talking about the wastegate actuator. On some of these it is operated direct from the compressor housing, almost as you describe (it is pressure driven, rather than vacuum). The replacement you have is not quite the correct one for your vehicle. You can probably get over this by connecting the actuator to a point on the intake manifold that is subjected to positive boost pressure.

 

[motovelo]

That sounds absolutely spot on, that's exactly how it works on my old turbo unit where as the new unit has a similar looking "vaccum like" housing on top and if I suck on the outlet connector the wastegate valve closes. Where exactly would I need to connect it to on the intake manifold , how would I know where there was positive pressure and is it a case of actually tapping a hole in the manifold and fitting some sort of connector? Would the van drive if I went ahead and fitted it anyway and sorted this later??

 

[Uncle Benz]

Hold it right there!! It sounds like the new one is vacuum driven rather than pressure driven. Compare the action with the old one when you suck on it.

This will cause some problems, as the vacuum driven device is controlled by an electrical solenoid, operated by the ECU - which you don't have.

The pressure controlled one is completely stand-alone, and has no ECU input at all. You might be able to swap over the actuator part if you are lucky...

You will probably get an overboost condition if you just bolt it on, which could cause some engine damage...

Or no boost at all. Depends whether the valve is open or closed at rest.

 

[motovelo]

The old one shows the wastegate closed where as on the new one it is open. It closes when I suck on the outlet pipe take off, have not tried this on the old one yet as like I said it connects straight into the turbo housing. As the unit is an exchange one and I have not fitted it yet I intend to ring the supplier tomorrow and see if I can swap it for the correct one. I just kind of hoped that after reading your earlier reply I would simply be able to tap a connector in the intake somewhere and save myself even more time off the road? But having just read your reply it sounds unlikely! Thanks for the swift reply by the way, it's appreciated. It's been a nightmare trying to sort this and has taken three days so far as it simply won't stop raining here!! I really hope after all of this it fixes the original problem which was whistling turbo and oil been sprayed all over the lower left hand side of the engine. Van has been dead reliable thus far and has covered a staggering 450,000 plus km!! Apart from the noisy diff (see various other threads) and prior to this turbo grief it's been a belter!

 

[Uncle Benz]

I'm glad you have the option to take it back. I am sure it is not the right one for your vehicle. Have a good look at the pipes before you get it back together - leaky boost pipes can spray a lot of oil mist about as well.

 

[motovelo]

All fixed! Correct turbo fitedt, normal engine service is resumed Now desperately trying to find a cost effective way to resolve the whining/singing rear diff!