MrBoost
16th August 2010, 00:14
I currently have a GT25R turbo on my Saxo VTR but am having some trouble getting the 1 bar of boost I want (8.5 comp).
I have connected up a bleed valve the 'wrong' way where the left hand of the T is connected to the inlet, the right hand of the T is open and the down stroke of the T goes to the actuator.
For testing purposes I closed the bleed screw completely which results in the actuator seeing no pressure at all, a quick test run showed a map reading of 190ish kpa which is what I want, I came of the throttle so I don't know if it would climb much higher than this.
The problem is if I unscrew the bleed screw the smallest amout possible (20th of a turn) the boost drops back down to 170ish kpa. It seems if the actuator sees any "high" boost (without the bleed valve boost was 140/150kpa) at all then its slamming the wastegate open. I have even tried putting a restrictor in the 6mm boost line to the actuator which only has a 1.5mm hole and it made no difference at all.
I think the spring or whatever it is that provides the resistance in the actuator is too weak, can this be modified or is there a replacement actuator for the gt25r I could swap in? If I cut the actuator arm and extended it would this be likely to help? Or would I be better swapping to a GT28?
I have connected up a bleed valve the 'wrong' way where the left hand of the T is connected to the inlet, the right hand of the T is open and the down stroke of the T goes to the actuator.
For testing purposes I closed the bleed screw completely which results in the actuator seeing no pressure at all, a quick test run showed a map reading of 190ish kpa which is what I want, I came of the throttle so I don't know if it would climb much higher than this.
The problem is if I unscrew the bleed screw the smallest amout possible (20th of a turn) the boost drops back down to 170ish kpa. It seems if the actuator sees any "high" boost (without the bleed valve boost was 140/150kpa) at all then its slamming the wastegate open. I have even tried putting a restrictor in the 6mm boost line to the actuator which only has a 1.5mm hole and it made no difference at all.
I think the spring or whatever it is that provides the resistance in the actuator is too weak, can this be modified or is there a replacement actuator for the gt25r I could swap in? If I cut the actuator arm and extended it would this be likely to help? Or would I be better swapping to a GT28?