Originally Posted by JohnAI love all this spring/preload talk. Put a decent actuator on the K16 and you get boost control working correctly.Originally Posted by JohnA
There is no reason you should need to play with preload on an electronic or decent pneumatically controlled boost system unless your actuator is not up to the job. Spring load is ONLY there to counter act gasses FORCING the wastegate flap open, this should occur WAY above your normal max boost pressure. Normal boost control is done by modulation boost pressure acting on the actuator diaphragm.
I currently have just enough tension set on a -31 actuator to hold the wastegate shut and make the actuator is in its useable zone. This is fine up to boost levels of about 20psi, more than that a -34 would do the job.
Using actuator preload as a boost control method reduces usable travel. On a tired/wrong actuator, you quite soon get to the point where this cause’s inconsistent boost as the wastegate cannot open far enough at high revs causing boost to rise over the normal.