Boost Dropping At Top End

[HSV ETR]

but I was running consistant 18 before or would be going soft? might go external gate if that's the prob

[IH8TOADS]

eBoost won't fix it

External gate won't fix it either

Mr 4.0 makes some good points

[Kroozin]

other than the valve springs, what else has changes since you were last running 18lbs and how long was it between running the 18lb tune and the new tune?

What have you tried so far?

[45T-XR]

Did you go to the larger exaust or get a port job in between your last tune and the new one? Removing the restriction could have decreased the back pressure on the cat side of the wastegate. This might have allowed the car to overboost as such to hold the boost uptop. I found the same issue with my own car, stock turbo and stock port job with 12lb actuator and xforce twin 2.5 system would hold 19psi to 6k rpm. Got the gate ported with big flapper and fitted twin 3" manta being the only changes, I could get it to peak at 19psi and fall over to 16psi by 6k rpm.

One thing you can try before upgrading the actuator is put more preload on the one you have to increase the cracking pressure. You would have to get a retune though as it would overshoot your desired boost around peak torque. And you dont have to pull the turbo off to do it, just unbolt the dump, the put compressed air in the wastegate like to open the gate, this swings the end of the actuator rod out passed the back of the exhaust housing, you can pop the circlip off with a seal pick, then shorten the rod 1 or 2 turns then reassble and get it to your tuner another go

[HSV ETR]

last tune was in august last year and the latest tune was done last week only things I did was atomic 4+ cams, springs and balancer,, port job was done well before the august tune

[HSV ETR]

after being at powerplay today me thinks I should hang a 42 off the cun7 anyways