Hi Lightspeed,
I’m currently running stock exhausts with the front baffles drilled out and the holes in the rear baffles drilled to a slightly larger diameter, intact cats, S&S Stealth high flow air filter, Stage 2 cams from Garage 56, and the Garage 56 ECU mapped for stage 2.
I originally installed the Morgan Aero Racing Stage 1 exhausts when I went to stage 1. Garage 56 reassured me their Stage 2 ECU would work fine with the Morgan Aero Racing Stage 1 exhausts claiming the Morgan stage 1 exhaust is similar in design to their Garage 56 exhaust which was used to map their stage 2 ECU.
So my engine still seems to run well with no loss of performance with the change to the modified stock exhausts.
My final recommendation for anybody wanting to go to stage 1 is to save some money and modify the stock exhaust by drilling out the front baffle, leave the cats alone, install a high flow air filter like the S&S Stealth, and use the stock ECU. I think you will be very happy. You only need a remapped ECU for the stage 2 cams.
Last edited by Sportster; 12/02/21 05:01 PM.
