Quote:
Originally Posted by G37sHKS
Gratz!!
No true dual Exhaust (2.5") for twin turbo families??  |
Its a hybrid of dual 2.5 and dual 3.0". And trust me, its far better for the turbo dyno curve.
I've seen what all dual 2.5" does and what all dual 3.0" does and neither provides the best overall performance in the 400HP-650HP range. They each have their compromises.
Having the 2.5" primaries on the XYZ tremendously helps the midrange and TQ for FI applications. I won't recommend 3" primaries unless you go to really high power. 700+HP.
Having the dual 3" past the collector provides the best HP.
It would have been cheaper and easier to manufacture the system all out of the same diameter tubing from front to back but that doesn't provide the best results on the dyno.
Having a progressively larger and larger diameter on the exhaust provides the best power results. FI or NA.
2.25" on the ART pipes.
Expanded to dual 2.5" on the XYZ primaries.
Expanded to dual 3.0" after the merge collector.
Small diameter pipes close to the engine increases scavenging but as the exhaust gas flows further and further away from the engine, scavenging has diminishing returns. Eventually it gets to the point where small diameter starts to create more pressure drop than scavenging and that kills HP.
It can't be too large and it cant be too small and it all depends on location.
That is why this exhaust has continually increasing flow area from front to back.
It dynos better this way.... and it sounds better too.