After a removing the stock 1 7/8" secondary cats for high flow 2.5" mandrel bent pipes, swapping for an E-fan, and adding a Split Second PSC-1 to adjust the wide open throttle air/fuel ratio that was rich above 5,000. Now I am ready for a set of headers and a 2.5 to single 3 or 3.5" exhaust using a true merge Y and a hooker aerochamber or Borla XS. I am ready to rid myself of the stock exhaust manifold/cat setup with their restrictive cat placement and 2 1/4" openings. Also on the list of stuff to be removed is the stock 2 1/8" od, 1.97" ID exhaust piping and 2.5" tail pipe. Its just not enough flow for a 360+ HP engine.

I gained ~5 RWTQ and ~3 RWHP peak to peak but gained 20-25 HP above 5,500. Going to the larger pipes and a slightly leaner a/f mixture might have hurt the torque slightly around 3,000-3,600 but its tough to tell, the truck has to be pedaled under ~3,400 to keep it from downshifting into passing gear.

 

So is this a stock setup? Nissan 5.6?

 

Mostly stock 2012 Nissan Titan.

The other mods were also on the truck in the first dyno chart that was overlayed by the one last Saturday.

Airaid MXP 4" CAI
Magnaflow DI/SO muffler swap on stock pipes
Hypertech 93 octane tuning with 0-60 WOT restriction removed, 2° timing advance, 33° total
180°F thermostat
DIY hand ported TB, with gasket screen removed and coolant bypassed