I need to come up with an exhaust system for my newly header-ed bmw 325is race car. I had been leaning toward a Y-pipe into a single 3" pipe out the back thru some sort of muffler. The 3" pipe seems to be the common choice for this car but that may not mean a lot as the most of the guys don't know much more (or less) than I do.

I talked to the tech support guy at flowmaster and he suggested that a single 2.5" would be help with the mid range (as opposed to 3") and flow better than the stock dual 2" pipes. At this point I'm leaning toward the flowmaster 50 for a muffler.

Any tips, hints or ideas would be greatly appreciated!

 

On our 325 Grand-Am Cup car, we used a single 2.5" pipe running out the back. It could not have been too restrictive as we had more power down the back straight at Daytona than most of the other BMW's