Fall apart under boost

ians13

New Member
Nov 8, 2005
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Jacksonville, fl
My brother just got a MK3 that was a NA but it has a jdm
7mgte ecu and every thing complete swap, It had a FCD hiding behind the glove box and a HKS timer hiding behind the steering collom cover, it also has a upgraded turbo of some sort it looks like a ct26 with a t3/t4 center section if that’s possible all I can tell is that the compressor wheel is bigger than a stock ct26 with no water inlet or out let? now the car runs good but I has a hesitation when you first hit the gas and when it hits full boost @ 10psi about 3500rpm it falls apart big time It don’t feel like detonation but it sounds bad and it wont go any faster I told him avoid boost for the time being,
Now my question is what the most common cause for this problem is so I can start to track it down.