I've adjusted my actuator rod?

[Trav85]

I was checking over the car a while ago and notice that the actuator rod had come off the arm.

I didn't realise I should've unplugged th vacuum hose to make moving the arm easier.

Anyway I had to unscrew to get it back on.

I've lost where it should be.

Since then I've installed needle and Dawes but no matter what I do I can't get it to spool up under 2000rpm.

I tow a van everyday so I need more low down...

Any help would be great.

[Rumcajs]

G'day mate.
 
I'm sorry but you've committed the "Cardinal sin" by Garrett, fiddling with the adjustable actuator rod. As far as them is concerned the turbo is a write off. Anyway I think its not all lost.
If you haven't touched stop/grub screw for max opening than it can be salvaged. I'm assuming you have lengthened the actuator rod.
 
With the engine running confirm that actuator lever goes up and lever touches the stop/grub screw, if it doesn't than the rod is too long hence vanes aren't opening fully and lack of boost bellow 2,000 RPM.
 
With engine off and vacuum hose disconnected, disconnect the rod from the lever and allow it to drop to its lowest position than via trial and error test the length until you get full up movement so the lever rests fully against the upper stop screw when engine is running. See pic bellow, ignore the instruction (in the picture) telling you to turn the stop screw in clockwise direction. Remember the goal is to get the actuator rod length right.
 
The problem with this approach is that min flow is impossible to set so the lowest point of the VNT actuator lever is not the best reference point in any case the max position is the goal, at certain vacuum pressure .....



Extra info (excerpt) from Garrett:

 

 

Garrett VNT™ Turbochargers To repair or not to repair

~ is it worth the risk?

By Trevor Cass, Garrett IAM Product Support Engineer (Europe, Middle East & Africa)

The turbocharger aftermarket has traditionally been

a place where a customer had the choice of buying a

brand new or a remanufactured turbo. However, the rapid

development of the turbo, alongside developments in

engines, fuel injection systems and engine management,

has meant that this must change.

In order to comply with strict emission controls, our turbos

have become much more technologically advanced – which,

in turn, means they are more difficult to repair. Because

the VNT™ is far more complex than a conventional turbo,

repair and remanufacture can’t be done correctly without

specialist equipment and information.

Indeed, even with the

equipment in our factory, we ourselves don’t remanufacture.

We know that new units are the risk-free option.

When we build new turbos we calibrate them to three decimal

places, with a number of checkpoints used to ensure correct

operation. A remanufactured turbo would also need to be

calibrated to the same degree of accuracy. But calibration

of a VNT™ turbo on its own is completely worthless without

the critical first stage being completed: setting the ‘minimum

vane open’ position.

The Garrett VNT™ components are manufactured to extremely

tight tolerances but, due to the large number of parts and

the clearances needed for the safe and efficient operation

of a VNT™, each individual turbo has to be tested and

adjusted after assembly, to ensure that it meets the engine

manufacturer ’s specified flow setting. Any disassembly of

the VNT™ turbo will mean that the minimum vane open

setting must be reset before the calibration process can be

completed.

We set the minimum flow vane position by using a calibrated

turbine flow bench which measures the actual airflow through

the vanes of every single VNT™ that we make, and allows

us to set and lock the minimum flow position to suit each

application. It is not possible to set the calibration of the

actuator to OE specification until the minimum vane open

position is set. Without a turbine flow bench, a remanufacturer

can only guess that the airflow is correct: the turbo may

operate, but it is highly unlikely that it will work to its optimum

efficiency.

 

Read the rest ==> http://www.turbo.com.sg/e-news/Garrett%20VNT%20-%20Non-repair%20buletin.pdf  think of it what you will....

Edited April 9, 2015 by Rumcajs