RV-14A with Superior XP-400 Installation Tips
Exhaust System
The Vans Lycoming IO-390 Exhaust System does not fit the Superior XP-400: you must buy a $1395 Vetterman Exhaust (currently a dual independent exhaust system with no crossover pipes) to fit the XP-400. The dual pipes do not enter the tunnel, but exit the cowl bottom anterior to the nose wheel hinge, so the cowl needs two cutouts adjacent to the nose wheel cutout - not a big deal.
The Vetterman Exhaust uses 2? pipes, which results in much lower back pressure than the Vans Single Exhaust pipe. Both Heat Exchange & Sound Mufflers can be added to the Vetterman Exhaust as the low profile Superior XP-400 Horizontal Cold Air Injection Manifold allows room under the lower cowl for muff/mufflers.
When you delete the Vans Exhaust from the Firewall Forward Kit, you also delete the cabin heat components: You must order 2" SCAT Tube, 10 hose clamps and the T- Splitter [VENT-00002] from Vans. A SCAT runs from the Fresh Air intake [CB-0007] located in the right cowl vent to a splitter, which shunts air to the right & left muffs. Another pair of SCATs connects the muffs to the Cabin Heat Valves.
If you want truly independent heat controls for both the pilot & copilot you must also order two FF-00084 Cabin Heat Valve Covers. Otherwise if one side is open and the other closed, most of the heat will shunt out the bottom of the closed valve.