I am considering removal of my OEM mufflers-partly for the weight reduction-partly for a more "robust" exhaust note. I would remove OEM by cutting exhaust pipe-replace with stainless pipe, utilizing stock tips. Has anyone done this? Is there a sound clip of the modified system? Ideas?? Suggestions? Comments?
Have you talked with an exhaust system professional before doing this Mufflers do more than just control the exhaust note -- they also help control noise and excessive vibration as well. Mufflers also help to maintain proper backpressure for your catalytic converters and your engine. Also, on a 335i, which is a turbocharged car, the exhaust system plays a crucial role in providing sufficient momentum for your car's turbos. That and you're not saving THAT much weight for this to be worth the potential trouble this could cause. Removing your mufflers may increase noise without increasing power (or possibly even a DROP in power), as well as resulting in a drop in your gas mileage, since unspent (unburned) exhaust gases and fuel will now be going straight to your catalytic converters. This could also cause early catalytic converter failure. The smell of raw fuel in your exhaust is a telltale sign something is not right with your car. But the worst is yet to come. If your vehicle is under warranty, and IF a BMW tech determines that any damage resulted from your modification of the exhaust system, you could find yourself on the hook for ALL repairs. If you haven't checked the cost of a BMW catalytic converter lately, the sticker shock might make you rethink this strategy. Best idea is that if you want to increase power and improve sound, stop being so cheap and buy a competent exhaust system with a warranty instead. There are plenty of competent vendors out there without butchering your car's exhaust. A correct aftermarket exhaust system, installed properly, won't violate your car's warranty, and if done right, won't harm the rest of your car's drivetrain. But silly stunts like you're suggesting just might.
To echo weir's thoughts, I don't know that it would be advisable to lose your mufflers without knowing exactly what the effects might be. Modern BMW's are as finely tuned as ever, and I'd think you stand a decent chance of having a poorly running car without a exhaust system designed and tuned for the car. Sure, that'd be a cheap way to modify your exhaust, but if the goal is a sportier sound, there are better options, even if costlier. If you cut the mufflers, I suspect it would be so loud that not only would it be intolerably loud, but that you'd also be making yourself a ticket magnet. No flying under the radar there, you could be heard doing a full-rev pull thru 3rd gear by some cop 10 blocks away, and furthermore, he'd be able to track you down by following the noise. More likely though, you'd get a noise ticket in just regular driving. Suit yourself, but I wouldn't recommend it. If you're looking for improved acceleration, even if losing the mufflers doesn't negatively affect engine performance, losing the weight of the mufflers I doubt will be noticeable by the 'butt-dyno'. Almost undoubtedly, tuning (which may even up the turbo boost) would do a lot more than dropping a few pounds.
I did this before I replaced the exhaust with an aftermarket one just to see what it sounded like. It's definitely too loud for daily driving and it rattles/vibrates your car. If I wanted it that loud I would put a cutout in the exhaust.
