In a nutshell, downpipes are illegal in the US due to toxic gas emissions, loud noises, and unpleasant odors.
Nevertheless, motorheads in many parts of the country continue to use downpipes to gain extra horsepower. They do not face penalties as some states have more tolerant laws on using such pipes.
In this article, I will talk about how different states enforce downpipe laws. I will also share several tips for sneakily using downpipes. Let’s get started!
What Is A Downpipe?
The downpipe is an exhaust pipe located near the turbine housing.
The primary purpose of a downpipe is to route exhaust gasses out of the turbine housing and into the exhaust system. Simply put, it facilitates the removal of exhaust gas more effectively.
Downpipes are available in two types at the moment.
- The first is a catted downpipe featuring two catalytic converters.
- The other type is the catless downpipe, which I will discuss further in the following paragraph. As the name implies, not even a single catalytic converter exists in a catless downpipe.
Is Catless Downpipe Bad For an Engine?
No, downpipes without cats are not always bad for engines. However, they are highly detrimental to the environment.
You are probably aware that a cat transforms harmful compounds into safe gasses. When there is no cat present, the gas cannot remain healthy. This is the sole reason why a downpipe emits toxic gases.
One thing to keep in mind is that you may see the Check Engine Light after installing the downpipe. The absence of catalytic converters is responsible for this.
Where Are Downpipes Legal?
Nowhere in the United States is it legally acceptable to attach a downpipe to your vehicle. Having said that, a few states do not impose a complete ban on the installation of downpipes.
Thus, you can roam freely in those areas, even with a downpipe mounted. Here is more information about it by region.
South Region
Are Catless Downpipes Illegal In Florida?
The Florida Statutes specifically forbid vehicles from using muffler bypasses, cutouts, or equivalent devices. This is a clear indication that you cannot replace your downpipe with an aftermarket one.
It is further stated in the statutes when you violate the rule; you will be charged with a noncriminal traffic infraction. Hence, you might want to reconsider your decision to use downpipes illegally in Florida.
Are Downpipes Legal In Texas?
Despite the fact that downpipes are not specifically mentioned in the Texas Code, most people will tell you they are illegal. It is because catless vehicles are incapable of passing emissions in Texas.
However, if you still intend to use a downpipe, ensure that the cat remains intact. In this way, whenever the time comes for an emission test, you simply have to reinstall it to pass.
Are Catless Downpipes Illegal In Georgia?
Catless downpipes are not legal in Georgia in accordance with the Official Code of Georgia. With a catless system, you are very likely to get caught since you have to go through a visual inspection in Georgia.
Nonetheless, it is a smart move to wait a few days, perform the inspection, and then install the downpipe. Another option is to find places where no visual inspection takes place.
Are Catless Downpipes Illegal In Virginia?
Under the Virginia Code, aftermarket downpipes are not allowed, especially the catless ones.
However, I know of a trick that can help you pass your OBD2 inspection in Virginia. Find a spacer that fits your car. Afterwards, you can use it to fool the scanner into thinking your car has a cat. Pretty simple, isn’t it?
Northeast Region
Are Catless Downpipes Illegal In PA?
Although downpipes are illegal in Pennsylvania, they are not explicitly prohibited in the 75 Pennsylvania Statutes. It focuses more on the noise limit that vehicles should maintain.
Therefore, as long as you do not exceed the noise limit, you should be fine with a downpipe.
Midwest Region
Are Catless Downpipes Illegal In Michigan?
According to Michigan Compiled Laws, your vehicle must have an exhaust system capable of preventing excessive noise. Unfortunately, a downpipe can be quite loud at times. Hence, it is illegal.
Having said that, if you can manage to keep the noise low, you will be fine driving around with a downpipe.
Are Catless Downpipes Illegal In Illinois?
The Illinois Vehicle Code clearly prohibits the installation of a cutout, bypass, or other similar devices in an exhaust system. I hate to disappoint the people of Illinois, but you are not allowed to install the downpipe on your beloved car while living there.
West Region
Is A Catless Downpipe Illegal In California?
As per the California Vehicle Code, you cannot equip your vehicle with a downpipe and go catless.
Some folks may still mount downpipes even though it is illegal. I would strongly urge you against doing so if you live in California. This is because the state enforces emissions laws very strictly.
To Sum Up
The use of downpipes is not permitted in the United States. Despite this, a significant number of vehicles are equipped with aftermarket downpipes. They rely on different tactics to avoid law enforcement, or sometimes the law doesn’t care about them at all.
However, do remember that downpipes still get caught and cause trouble when inspections or other tests are conducted.
Curious if straight pipes are legal where you live? Take a look at this article to find out.
