No way will you only see 8psi with the impeller. I had the Stillen Stock pully (8psi) and the impeller upgrade from Vortch same as the 928 and was seeing 11-12 PSI. I had no other mods the the SC or differnt pulley. I have a thread on hear all about my run at 500 WHP. Name of thread is Stillen500 WHP. You will need a new tune because you wil see more PSI.
btw 500 WHP on their kit will not happen
just be happy with mid 400's .
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14 Q50 AWD, ARK, ECUTEK (SEB), Takda,
