Originally Posted by
D-Rob
It has everything to do with entry angle from the collector and laminar flow of exhaust gas against the outside of the tubing. The wastegate entry on that manifold is EXACTLY the same as the old Peakboost junk; backwards to flow. Combine that with a decent sized turbo, and you've got a recipe for creep (unless you plan on running real high pressure all the time).
Exhaust gases take the path of least resistance, even when exhaust pressure exists pre-turbine. In the case of today's super-efficient exhaust wheel technology, combined with a high-flow cylinder head that's moving a lot of air, proper FLOW to the gate is what's going to help the most in terms of boost control.
Here's a crude paint drawing of exhaust flow inside two different manifolds. One having an against-flow entry, and "one going with the grain."
I know it isn't the most technical drawing, but you get the idea.
I have tuned countless amount of turbocharged K-Series, and have a pretty good idea of what manifolds work, and which ones falter.
Bookmarks