by David Gentleman » Sun Oct 08, 2006 12:27 pm
Depends on the application. Ext. Wg's normally suit large turbo applications running low/moderate boost, where basically most of the exhaust gas doesnt need to run through the turbine wheel, so it needs to be diverted through a free flowing wastegate..because, if it wasnt free flowing, the turbine pressure would back up and end up pushing the turbine wheel faster and getting boost creep...
Likewise, on a smaller turbo setup running high boost, you need most of the exhaust energy to go through the turbine wheel to maintain the high boost pressures.
Doing it on a GTA is difficult, because it needs to be plumbed in the common part where the manifold meet, at the backplate basically.
Ext Wg, are nore of a need than a power increasing item. They are just a good way of controlling boost (if you application needs it). If you have a setup, where the boost is solid, no creep etc, then you won't see any real gains except from a slight drop in exhaust restriction, but if you exhaust system is designed properly to start with, then you may not see any real benefits..
Installation on a Turbo2 would be easy, as it has a tubular manifold to start with, so plumbing one in with a screamer pipe would be quite straightforward.