have a 9, running stock turbo, basic bolton's, cossi cams and snow alky kit.
car ran fine prior to alky tuning, and would hold 21psi, tapering off to 17-18. turned up the boost to 28 during tuning session and it shoots to 28, drops to 24, back up to 26-27 then starts falling. Jestr tuned the car and can see the noticable boost surging. thought it was the forge mbc, so swapped out for a hallman, and same issue.
anyone know where to look for this? everything is ran correctly as far as vacuum lines.
do I need an upgraded wastegate actuator to run more boost? boost leak?

thoughts...

 

it's normal.

 

jestr didn't seem to think so.

 

It spikes, then tapers,then creeps on alky, finally tapering one last time at high boost levels. This behaviour is, if not normal, then, at least within the realm of possibilities, for an Evo using the IX turbo on alky.

The Forge WGA equipped with red spring might help as would porting the turbine housing´s wastegate bypass port("hole") to alleviate backpressure within the scroll and fascilitate venting of excess turbine flow. With these two measures you should be able to experience rock steady boost control once again.