to spool it faster you are going to need to increase the target boost in the table to correct boost at the correct rpm then increase the wastegate at that rpm to spool it
to fix the tapering issue you want to progressively increase the wastegate as the rpms go up.
say
if it was at 4000rpm, 0 then 4000rpm, 5
if it was at 5000rpm, 0 then 5000rpm, 10
if it was at 6000rpm, 0 then 6000rpm, 15
begin this where it begins to taper
if it does not respond to increased wastegate then you may just need a bigger turbo
do 3rd gear pulls to check the boost
in 4th boost will be a little higher
what kinda boost are you looking to run on what turbo? is this still on the 2.0?
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