Almost everyone's got an opinion about car exhaust upgrades, mostly because out of all of the mods you can make to your vehicle this is the one that is easiest to notice as its wail cuts through the night in a normally quiet urban subdivision. Most bad exhaust mods end up making a car or truck way louder than it needs to be, regardless of what impact it may have on engine performance or the sanity of those forced into close proximity with its mega-decibel audio dump.
Each of the following exhaust upgrades are surefire ways to become the least popular person in your family/office/neighborhood, or at the very least, make you the easiest targets for ticket-happy law enforcement.
Hater Pipes And Stacks
Whether they're sticking up behind the cab of your pickup or piercing through your hood, exhaust pipes were never meant to stand at attention on anything other than your uncle's 18 wheeler. And yet there's an entire subculture centered around the idea that the more visible your exhaust pipes are, the more horsepower they're somehow adding to your no doubt finely-tuned engine setup, with the ultimate goal for them to be observable from space.
If you're in a truck, then those pipes better be scraping the ceiling in whatever parking garage is echoing the cannonading sound of your diesel rig.
If you're in a car, it's best for each individual pipe to block as much of your forward vision as possible. Either way, you're looking at a pair of projectiles that will most likely impale you, your passengers, or any pedestrians unlucky enough to be within stabbing distance when you lose control after 'unleashing the beast' one too many times on a rain-slicked road.
Whistle Tips
Who can forget the national news story that put Bubb Rubb and Lil Sis at the forefront of the whistle tip exhaust phenomenon that exploded out of Oakland, California, nearly two decades ago? These high-pitched cop callers produce the world's most annoying sound at an extremely high volume, and all you have to do to make instant friends with each of your neighbors is attach them to your muffler and go for a drive as early in the morning as possible.
It's impossible to come up with a case for defending the existence of whistle tips. They are the automotive equivalent of a whoopee cushion, a practical joke you'd play on friend in the hopes that they'd catch a ticket. Somehow, there are some people who actually pay money for these things to deface their vehicle's sonic signature in the worst possible way.
Side Pipes
This particular bad exhaust mod comes with an asterisk: if your vintage car originally came with side pipes, then it's almost always cool. Muscle era Corvettes, AMC Trendsetters and Sidewinders, lake pipes on a hot rod, even that weird period in the 1970s where Mopar decided that side pipes were going to save its decidedly milquetoast mid-decade line-up: all get a pass.
On every other car made after 1980 (with the exception, of course, of the Dodge Viper), side pipes are a terrible idea. If someone approached you with a product that was guaranteed to melt the polyester in your pants directly onto your skin each and every time you stepped out of your car, while simultaneously bubbling your paint and making you deaf in your left ear, you probably wouldn't buy it.
Right?
Test Pipes
Once upon a time, catalytic converters were a plague that sapped horsepower and absolutely murdered engine performance. After two decades of refinement, however, the inexorable march of technology had automakers building mighty V8s and deep-breathing turbocharged engines without any negative impact from the presence of this by-now ubiquitous eco-friendly component.
Anyone who makes the argument with a straight face that a high flow cat the size of one's fist or forearm is going to somehow cost them more than a single horsepower or two at maximum RPM is living in the past. It used to be cool to hate the environment if you were a gearhead, but nowadays wouldn't you rather be known for the piercing volume of your whistle tip rather than the cloud of toxic fumes that trails your vehicle wherever you go?
Straight Pipes
It's a short step from running a test pipe to a full straight pipes setup, which deletes everything after of the headers—mufflers, catalytic converters, and resonators—in favor of an almost unfettered exhaust note. While this might seem like a glorious idea, especially for the first 30 seconds or so after you turn the ignition key post-installation, transforming your vehicle into a vibrating box of ultra-loud resonant frequencies quickly loses its charm. This goes both for you and those subjected to your morning cold starts.
It won't be long before you find yourself upshifting at 1,200 rpm in a frantic effort to preserve your sanity and avoid the dreaded drone of your engine under steady state cruising, all the while fantasizing about the aggressive-under-acceleration, but mellow-during-daily-driving tone of your old muffler. Who knew that those billions of dollars of research and development into exhaust systems could come up with a better result than your decision to just stuff a 3-inch pipe under your vehicle?