Quote Originally Posted by tweek View Post
Someone tell me tho what would be wrong with welding up the wastegate penny and using an external wastegate it serves the same function as a boost controller and u get a class noise at full boost??apart from using the standard manifold whats wrong?
Is that a serious question?

Ok well put it this way, if you want to increase the bore of your cylinders do you just drill them out with a hole saw?

Turbos and manifolds are all about flow dinamics and welding up a place where the gas is supposed to and hoping that it will find its way out another way is just pure bandit.
The more technical reason is that the design of the standard manifold is one that flows the exhaust gasses towards the turbo in the best and most even way, so by cutting a hole in it and allowing the gas to escape through a retro fitted wastegate you'll be causing major pressure and flow issues within the manifold and the same is true of welding up the internal waste gate.