Tuner culture has existed for a long time, but it was popularized in the mid 2000’s by Xzibit’s show “Pimp My Ride.” While the success of this show has made affordable car mods available to normal consumers, it can be tricky to know whether or not a given mod will be “street legal.”
Here’s a quick rundown on what things you can do to your car in California.
How powerful can you make your car? It turns out that there’s a pretty short list of things you’re allowed to do to your engine in Cali. First of all, the engine itself has to be certified by the state for use on the road. This means you’re pretty much limited to using the engine from a normal production car. Even engines that are certified for use in other states or by the EPA aren’t allowed unless they’re also certified by California.
More importantly, however, the parts that you use have to work with your engine. Either the EPA or the ARB has to “sign off” on all of the cams, pistons, intakes, and other parts that you use as being compatible with the exact engine in your car. While some parts are “exempted” by the ARB to work with any engine, this limitation still means you can’t go crazy.
You still have to pass smog, too. Your modified car is still subject to normal smog checks at an official station, and the emission control unit has to be certified to work with cars as new or newer than your car. In other words, your exhaust is a pretty big deal as far as keeping your car mods legal.
You can do quite a lot of body work on a car without impeding its street-legal status. One important rule to keep in mind has to do with frame height. California breaks cars up into three categories: less than 4,500 lbs Gross Vehicle Weight Rating, 4501 to 7,500 GVWR, and 7,501 to 10,000 GVWR. Each category can have a frame height of no more than 27”, 30”, and 31” respectively. The bottom line here is that you can’t jack your car up too high.
Two other rules to be mindful of: body lifts cant exceed five inches, and the tallest part of your vehicle can’t be higher than 14 feet. The second rule primarily exists to let your car fit under bridges, while lift kit regulation keeps everyone safe in the event of an accident.
What about your headlights? California’s rules are designed to make sure you’re respectful of other drivers when you modify your car’s illumination systems. The two big rules limit you to two lights with “white” lamps and regulate any lights used to 32 candlepower or less. The lights also can’t light up more than 300 feet of road, which can often be fixed by adjusting the angle of your headlamps.
There are a few other rules that regulate how many lights you can have active. Only two fog lights are permitted, total, and only four lamps can be turned on at once. Again, this serves to make sure that you’re not blinding other drivers with the brilliance of your new car mod.
You can tint many of your windows in California, but not all of them. Only the top four inches of the front windows are supposed to be tinted, which lets you block out some sun rays while you drive. The front windows must let 70% of light through, which means they can’t be particularly dark. On the other hand, your rear windows and back windshield can be as dark as you want, which gives you lots of freedom to customize. The only limit here is how reflective your windows can be. Any reflective tint can’t send more light back than a “standard” window.
Finally, and most importantly, California limits muffler mods pretty strictly. The rule is worded in a complicated way: you can’t modify the exhaust system in a way that makes the car louder than a stock factory car. This means you can make your car louder with other modifications (by installing a more powerful engine, for example) as long as any exhaust mods only make your car quieter. It’s worth noting that even if your loud car is technically legal, you might still get pulled over or harassed by police if it’s noticeably louder than a stock car.
There is a hard cap on engine noise of 95 decibels. This is pretty high, but if you’re going crazy with car mods, it’s definitely worth taking a few minutes to text the decibel output of your engine. This can save you quite a lot of money on costly tickets!
Finally, what about your sound system? The rules here are pretty vague: while you’re on a highway, your sound system can’t be audible from 50 feet away. This doesn’t limit you from installing whatever system of amps and speakers you want. What it does mean is that you should be mindful of other drivers and keep your killer sound system turned to a reasonable volume while you drive.