gartam wrote:Change dump pipe, make sure there is no cat in it and a straight through exhaust.
That will more likely cause the hearts of the global warming fraternity to flutter.
Turbo flutter occurs on the inlet side, not the exhaust, when the pressure builds up in the system to the point that the inlet vanes chop through the air, rather than cutting through and pushing it, under increased pressure down to the intercooler. The increased pressure is usually induced by lifting off, causing the throttle valve to close. Pressure is controlled by a waste gate on the exhaust side that allows exhaust to effectively bypass the turbo and the inlet side to reduce compressing the air in the inlet system. By delaying the action of the waste gate some turbo flutter may be induced, but it needs to be done carefully and there should be a failsafe (Dawes valve or blow off valve) incorporated into the system to ensure that pressure doesn't build to dangerous levels.
There is discussion on the various mods that can be done in threads linked in
this search.