Going to attempt to increase the preload abit on my ALH 1.9tdi. 
I'll get myself a boost gauge first, I realise too much preload and it'll go into limp mode.

 

Anyone done it on the 1.9tdi? 

I would exercise caution trying to make gains this way. Limp mode could be the least of your problems in the end...

Suppose the question is why are you feeling the need to do it? I can't really offer specific advice for tdi, just generally, sure someone here can. Anyway if there is a real need to do so I would mark the nut so you know when 1 full turn of the nut is, and do 1 full turn at a time. But yes like I say, why do you want to?

Mainly because I can. The car has 216k on it, so isn't worth anything. 
Will be no longer used to take me to and from work soon so will just be used if I fancy driving to the shops or going places.

 

So plan would be:
Lube up actuator nuts every day for a week or so.

fit boost gauge

check standard pressure (7psi I believe?)
mark

one full turn

check pressure

repeat as neccesary

Sounds like you've answered your own question. Not sure what cracking pressure is for tdi. It's 5 psi for the 1.8t. Log boost with n75 unplugged and you'll find out for sure.

Cracking pressure?
When you say log boost, do you mean with vcds and laptop? 
I guess unplugging the n75 stops the ECU controlling the boost?

Yeah unplugging n75 runs on actuator pressure only which gives your theoretical minimum boost pressure. Thought that's what you meant by standard pressure.

You can use your boost gauge but vcds is more accurate plus you can plot the readings on a line graph to see how the curve compares to what is being requested.

The main problem is crossing the threshold into increasing exhaust gas temperatures as the wastegate is reduced in capacity by winding the nuts up the rod, which becomes counterproductive in the end. Iirc each full turn of the nut equates to a third of a psi in the 1.8t petrol. Probably differs for yours but gives you a ball park figure. I'd be wary of going more than 3 full turns though in reference to the problem just mentioned. By all means have a play around, be interesting to hear your results.

Thanks for the info yellowcar. 
Unfortunately I don't have VCDS, I used to have a ebay cable, but updated the VCDS software and it fried a chip in the cable (VCDS has built this into the software now so you can only use there cables I am led to believe) 

I know the real VCDS is mega money, any alternatives?

 

Is pre-loading the actuator the same principle as going from a green to yellow spring on the 1.8t?
 

It won't be getting done for at least afew weeks, still have to use the car every day currently.

If you have an android or apple phone you could try the torque app which requires a bluetooth obd2 plug in. Although it's not easy to find one that works, I've tried 2 now and failed. Other people have made them work often on 2nd attempt!

Preloading isn't the same as spring tuning. This is where my tech knowledge falters a little. Spring tuning the actuator means you can run higher boost levels and the wastegate is still able to overcome the increased pressure to shut again higher up to maintain boost. Adding preload cranks up boost by raising the cracking pressure and reducing the wastegate. You can do preload to overcome weaknesses in the actuator spring (which can happen after mapping) but it's not really advised as a tuning method.

I'm actually suffering from a weakening actuator at the moment, both spring and the diaphragm inside is perishing I believe. What I've done is added an external tension spring hooked round vacuum hose and the rod to give the spring some extra oomph to help it shut again. This doesn't hold it shut, it just makes it stronger. As such I hold peak boost of 19 psi for a little longer and it doesn't drop below specified until higher up the rev range near redline. This is the same as using a spring adjustable actuator, pikey style. But if there is nothing wrong with your actuator and you're not remapped I don't think this would do much for you. It's a bit of a minefield this and I'm learning myself. I have a refurbished actuator to fit I just can't seem to get round to it.

Through trial and error I found a tighter spring than my first attempt and it boosted silly amounts like 23psi basically because actuator was too strong and probably couldn't open fully. Was quite scary actually. I'll see if I can dig out the link so you can see what I mean.

http://www.briskoda.net/forums/topic/352295-pikey-mod/?hl=%2Bpikey+%2Bmod#entry4223226