I recently added a 3 inch turbo back catless exhaust to my 04 WRX. DP, UP, cold air intake, and 4.5 inch tip. As stated no cat's and 3 inches from turbo to muffler. Car was then tuned, boost increased, timing advanced, and it was running like a champ at "full stage 2". At any rate EVERYONE complained about the noise. So I went to an exhaust shop and asked to get a different muffler (like a magnaflow) put on to quiet it up a bit. $290 later they cut my exhaust and welded on a muffler. Problem is although it is dramatically quieter I seem to feel a power loss. Last night I look at the muffler and realize a couple things.....
First it is NOT a magnaflow. Second although it is 3 in and 3 out it is only like 2.5 internally. I can see pretty much straight through the muffler but I swear I feel restriction.
Am I tripping or did I just make a mistake? I am going to swing by my tuner (Horizontal Motorsports) today during lunch to review but I have no desire to lose power, only lose sound. Would 3 inch internal vs 2.5 inch make that much of a difference? I am still running on the stock turbo and intercooler if that matters. But my question is should I go back and demand something with the 3 inch internal or am I just allowing my butt dyno to lead me astray?
The exhaust shop gave me 2 days to come back if not satisfied. If the performance is there then I am happy.....if it is not then I am not.