57trim with hafe manifold question

[Lou98GSX]

I have a 98gsx eclipse with a 57trim bb trubo, hafe manifold with 38mm external wastegate to atmosphere, hks264 cams, dsmlink and couple other bolt on's. My question is ever since i switched from internal wg to external the rpms do not have a smooth increase in higher rpms around 6k to 7k. The car feels as in it is holding back.
Everything is hooked up correctly i have years of technition experience but this is driving me crazy.

Could it be that the hafe manifold does not have the divider at the collector as the oem manifold does??

Please help with my problem

 

[brute]

Do you know what spring you have in your wastegate?

 

[Lou98GSX]

spring size is 21

forgot to mention that i have my boost set at 25 and runing meth injection and i didnt have this problem before with stock manifold and fp green turbo with internal wastegate

 

[Lou98GSX]

finally fixed my problem i took 2 springs out of my external wastegate and left the gray 14 psi one in there turned up the boost to 25psi and now i can rev to 8000 rpm with no problem . car feals fast again . time to turn up the boost .