As the title states. I have an off the shelf S475 and a Stock LQ4 (ls9 head gaskets, arp head bolts, comp 918 springs). I have a set of obx shorty headers that I want to flip, or maybe some truck manifolds if they would hold the heat better and help spool time. What is the best way to build the hotside, dual 2.25" to a merge just before the turbo or dual 2.25" straight to each side of the t6 flange? The is truck is street driven but see's the track 10 or so times a year, so I'd like it to spool as quickly as possible. Also if I run 2 seperate pipes to the turbo is it better to build a merge and run one big wastegate or 2 small seperate ones? This is my first turbo build so I'm hoping to get it right the first time, so any help is appreciated.

 

Twin scroll spool quicker. But the turbine size and ar play a bigger part.

 

Thanks, that's what I figured. I'm going to run dual 2.25" and dual wastegates.