Part throttle boost issues

[Yamahaulin]

I have been having this problem for quite some time and i have since replaced the bov and wastegate and I still have the problem. I run a punishiment racing manifold with a PTE PW46 external wastegate with a Tial Q 50mm BOV. Lets say i'm accelerating but not full throttle, i hit 10 psi and I want to stay there so i stay accelerating just a bit but not enough to make more boost. My problem is that the boost is realeased, i either have to accelerate alot more to make more boost I can not hold a constant boost pressure. Seems like i should be able to let off a bit and back the boost down without releasing it. Is this normal or do i have a problem somewhere. Some days the problem is worse than others, on good days i can back the boost down from 10 to 5 with letting off barely and somedays it's just like I slam the throttle shut and it's all released, even though i didn't slam throttle shut i just slightly back off.

 

[Yamahaulin]

Is this completely uncharted territory here?

 

[sstigijr]

It sounds like your BOV needs a stiffer spring. It's opening too much at part throttle.

 

[Yamahaulin]

I'll try a stiffer spring then.

 

[Yamahaulin]

Is it common to have to run the stiffest spring Tial makes, cause right now i have the silver one that's supposed to be right under the stiffest one if i'm reading them correctly. For the amount of vacuum the car has at idle the silver is the recommended spring.