What's The Difference Between C.A.R.B. Compliant Car Parts Vs. Ones That California Bans?

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If you have ever shopped for catalytic converters or aftermarket performance parts, you might have noticed that some parts are listed as "C.A.R.B. compliant" and others as "49-state" or "Federally legal." And you probably noticed that the C.A.R.B. legal parts are way more expensive than their federally legal equivalents. This is because C.A.R.B., or the California Air Research Board, sets stricter emissions standards for vehicles than the rest of the country. As such, any aftermarket parts that affect the emissions system need to be C.A.R.B. certified. This means manufacturers need to prove that their parts do not increase a vehicle's emissions or face hefty fines like Cobb Tuning did a few years ago. 

Parts makers may be tempted to tell the Golden State to kick rocks and not sell parts there, but California registers 1.8 million cars and trucks annually. To ignore that market would be to ignore one of the biggest new car markets in the U.S. So, in order to sell parts to Californians, manufacturers must go through an intensive testing process to make their parts C.A.R.B. legal. 

An aftermarket performance part installed anywhere from the intake to the catalytic converter can affect emissions equipment in the eyes of the EPA. This applies to air intakes, ECU tunes, headers, non-OEM replacement catalytic converters, and superchargers. For an emissions-related part to be legal in California, it needs an Executive Order (EO) from C.A.R.B. An EO is basically a paperwork trail that proves the part does not increase emissions and is exempted from emissions anti-tampering laws. 

A manufacturer must file the right paperwork with C.A.R.B. and have emissions testing performed at an approved lab in order to obtain an EO. If you think that the extra paperwork and testing sounds time consuming and expensive, you'd be right. But if the part passes, it is issued an EO number that is unique to a specific application (e.g., an air intake for a 2015 to 2017 Ford Mustang with the 5.0-liter V8). C.A.R.B. approved parts come with a sticker or tag displaying the EO number so emissions testers can verify that the part is compliant. If a part has an EO number but isn't installed in the right car, or if an EO part is modified, it is illegal, and your car won't pass emissions testing.

The benefit of C.A.R.B. approved parts is that you can increase your car's horsepower without increasing its emissions or running afoul of the law. However, the downside is often increased cost. For example, in California and other states following the C.A.R.B. standard, aftermarket catalytic converters must last 5 years or 50,000 miles. The EPA standard is 2 years or 24,000 miles. To meet this standard, the California-legal converters need more of the rare precious metals, like platinum, palladium, and rhodium, that convert an engine's toxic exhaust into something more benign. 

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It may seem strange that a state agency has such a considerable influence on the environmental regulations of the U.S. But the authority C.A.R.B. wields is not an accident and didn't happen overnight. Smog, the toxic byproduct of unburnt fuel from cars mixing with nitrogen oxides, was a huge problem in the U.S., particularly after the population and economic boom following World War II. California had some of the worst air quality in the nation, due to its growing population, reliance on cars, and climate and topography. 

On especially bad days, the thick smog caused bad eye and lung irritation, and visibility was down to just a few blocks. Because the air was so bad, California was the first state to regulate vehicle emissions in 1966. But it wasn't until 1967 that C.A.R.B. was created to unify the state's approach to fighting smog. When the the EPA was established, federal regulators largely deferred to California when setting regulations because the state was already ahead of the game when it came to controlling car emissions. Also, due to then governor Ronald Regan's petitioning, California was able to retain its ability to set stricter emission standards than the rest of the country. 

C.A.R.B. and its ability to set different standards than the rest of the country remain controversial, with the Trump administration repeatedly attempting to strike down California's emissions standards.  But without some of the emissions technology that California has championed through regulation, like positive crankcase ventilation (PCV) systems, catalytic converters, and onboard diagnostics, our air would certainly be a lot dirtier.