Originally Posted by Rossco

Um, you might have missed the point buddy.

Virtually all turbo's will boost high & hard with the boost line disconnected from the actuator. (E.G My actuator line split & it hit the 1.75 bar ECU overboost cut)

There simply isn't enough exhaust gas pressure internally to force the wg open against the spring pressure alone...... The actuator requires the pressure line from the comp housing to work as designed!

Remember my base wg pressure is only 13psi, that split hose saw a boost peak of 25.5psi on my set up - see my point?

(In fact I can run anywhere from 13 - 30psi on my set up, my WG duty for 28psi is only 45%)

You need to determine your gate pressure by bypassing the solenoid - but running a line from the comp housing directly to the wg actuator is the only way - there is no otherway to do this safely or accurately.

This will tell you your TRUE base line 'waste gate pressure' and will tell you a butt load about your set up.

I'm not flogging a dead horse here, but you need to properly determine you base line boost pressure before trying to find other faults that may not exist.



Grimspeed use rebranded MAC valves - I've only ever seen one fail (leaky valve seat) and that caused random boost spikes.