11. Vanity Shift Knobs
From the classic $20 eight-ball to a hand grenade for $85, you can dress up your shift knob with just about anything — including a crushed can of PBR or a hunk of “Jurassic Park” mosquito amber. But the truth is, vanity shift knobs rarely add character unless you’re dealing with a meticulously restored classic car. Most of these knobs are dated and juvenile — and they can inhibit proper shifting.
12. Intake Vortex Devices
Like so many other fuel-efficiency products that make empty promises, intake vortex devices rely on drivers’ misunderstanding of how modern engines work.
The promise that cars can benefit from add-ons like intake vortex devices — which attempt to alter the amount of airflow into the combustion chamber — ignores the fact that today’s cars already rely on complex computers to continuously adjust airflow to match fuel intake, and vice versa.
13. Hydrogen Generators
This class of fuel-efficiency gimmickry is based on the idea that hydrogen is a more powerful fuel than gasoline. Even if that theory holds some element of truth, it’s simply not practical for cars.
Hydrogen generators claim to create hydrogen by separating it from oxygen found in your car’s water supply and redirecting it to your fuel supply. One problem is that the kind of electrolysis devices used for this only produce the tiniest amounts of hydrogen. In order to do so, they place enormous strain on your alternator, which they use to bleed power from your vehicle’s electrical system.
14. Fuel Vapor Injectors
Like the other so-called fuel-enhancing devices, the concept of fuel vapor injectors doesn’t pass muster with people who understand how engines work. By adding this fuel-vaporizing device, the best you can hope for is performance identical to that which you would have achieved if you had let your factory-installed fuel-injection system do the heavy lifting.
At worst, a fuel vapor injector can degrade performance by forcing your engine to run “rich” with too much fuel and not enough air. When it comes to so-called fuel enhancers, ask yourself this: Why wouldn’t manufacturers simply add these devices in the factory if real fuel savings could be achieved by including a part that only costs a few bucks?
15. Racing Engine Simulators
If you want to pretend you’re driving a race car, any arcade in America can accommodate that fantasy for just a few quarters. That’s a much better outcome than dropping $40 on a sound simulator, many of which get poor reviews because they’re cheaply made and wind up offering only a distraction.
In the case of ultra-quiet electric engines, adding sound can bolster safety. But driving a Camry modified with a contraption that plays the prerecorded sound of a Shelby engine is unnecessary. It’s also an energy hog, and — just as with fake performance badges — kind of sad.