Here is the stock AP2 cat with the heat shield removed. Honda used narrow angle diffuser and nozzle to minimize pressure drop going into the cores. Yup, Honda squeezed out performance everywhere.
It’s a bit tough to see as it’s out of focus, the front brick came loose and smashed the rear O2 sensor leaving a dent in the core. The car had developed a rattle and that rattle was the core shaking around.
Hey, it’s tight in there but it all fits! In case you were wondering, that rubber tube should be the condensate drain tube from the evaporator of the air conditioner.
The team at Eimer Engineering welded a brace between the wastegate recirculation tube and the main 3” exhaust to prevent the wastegate tube from cracking where it merges into the main pipe. The merge is a nice narrow-angle merge for low back pressure on the turbine.
Eimer Engineering decided to clock the turbo a bit to create some more space for routing the compressor discharge pipe and also to create more clearance to the Improved Racing remote oil filter adapter and oil cooler coolant line coming out of the block. The coolant hoses are looped to bypass the stock oil cooler which was removed while I was trying out the whole oil filter mount/cooler/sandwich stack.
The braided stainless-steel line you see is the coolant feed to the turbo. It will be on the engine block side and going into a bottom port on the center housing of the turbo. The coolant outlet is on the frame rail side and going upwards. This orientation of cool coolant feed going in the bottom and hot coolant going out the top is to promote syphoning when the engine is not running. I got these lines pre-fabbed from ATP Turbo.