I have stock dual 330i exhaust pipes from a 2001 330Ci with both resonators deleted welded to a Supersprint muffler. I've been reading this thread and it is very interesting. Am I right to conclude what I believe I have learned?
1. It seems like going from dual to single will mainly save weight.
2. Whilst Y pipe length/taper & positioning for a single determines whether you have more torque down below or up high.
The next question is I need to replace the pipes on my car as the old ghetto welds are starting to show signs of wear and I am getting vibration inside the pipes. I was toying with the idea of going for a 3" single, but it seems like having a 3" single is great for up to 700hp and my car has nowhere close to 300hp. My friend at the shop was saying all I'd need is 2.75" single to maintain street clearance height from the pipe. Would going to a single pipe with stock headers/TB make any difference? If it saves a lot of weight then I guess that's probably one of the only things that help the vehicle in less mass rather than n/a bolt ons. If I were to choose a torque curve, I would want performance for the street which is low end torque. My car doesn't get timed at a track when I'm there so that's not an issue for me right now.
I need to make a decision soon as my car is sounding more and more like an old rusted Oldsmobile day by day....LOL. If you guys have advice in what is best for this application, then it would be great. I'd still love to have a nice deep sound and I've just learned that welding on different length closed canisters to the end of the exhaust will help control drone. Seems like exhaust systems is quite an art to understand and I know I'm just learning the tip of it!