thats what im trying to figure out? and just out of curiosity? When did that thing spool?r34 gtr wrote:going with something bigger?
4500rpm full boost!nissanic89 wrote:thats what im trying to figure out? and just out of curiosity? When did that thing spool?
Garrett Trubos wrote:A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds.
The concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine's exhaust pulse energy.
For example, on a four-cylinder engine with firing order 1-3-4-2, cylinder #1 is ending its expansion stroke and opening its exhaust valve while cylinder #2 still has its exhaust valve open (cylinder #2 is in its overlap period). In an undivided exhaust manifold, this pressure pulse from cylinder #1's exhaust blowdown event is much more likely to contaminate cylinder #2 with high pressure exhaust gas. Not only does this hurt cylinder #2's ability to breathe properly, but this pulse energy would have been better utilized in the turbine.
The proper grouping for this engine is to keep complementary cylinders grouped together-- #1 and #4 are complementary; as are cylinders #2 and #3.
Because of the better utilization of the exhaust pulse energy, the turbine's performance is improved and boost increases more quickly.