[quote name='ging' timestamp='1325800265' post='159638']
thourght the st170 wasn't turbo charged ??
ok mate, just the spooling of the turbo or time it takes to reach top preissure can cause turbo lag, on any turbo
then when it picks up you get the kick of boost, fitting a dump valve system would help the turbo reach top running speed quicker
but its pointless buying one unless you know for sure that is the problem, i sympathise with you mate you have put alot of work in to that motor hope its easy fixed for you.