- A cat back exhaust system replaces everything “In back of” the catalytic converter
- An axle back exhaust system replaces everything “In the back of” the rear axle
- There are certain noise limits that would limit the use of certain exhaust systems
- A cat back exhaust system can offer a large increase in horsepower
- A full cat back exhaust can give you up to 10% fuel savings!
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An aftermarket cat back exhaust system is one of the first upgrades truck owners perform on their trucks. It is a generally simple bolt-on system that most people can do with limited tools. It provides an instant change in sound. It can turn tame trucks into full-out beasts!
Performance-wise some are well worth it while others don’t give you a whole lot of oomph.
Ever gone to a car show and found yourself mesmerized by the sound of a cat back exhaust system? If so, you’re not alone. The roar from those pipes is as sweet as it gets, but there are some questions you should be asking yourself before going out and getting one for your ride.
According to some experts, aftermarket exhaust systems can damage your car in ways you’d never imagine.
What they don’t tell you is that cars are actually louder and more aggressive because of the exhaust. An aftermarket car exhaust will make your car faster and give you a chance to be heard amongst all the other cars in traffic. Proper tuning will neutralize any potential damage from a modified exhaust beyond the normal wear and tear if done right.
But overall a cat back exhaust system can be an expensive mod that may not be for everybody. There are other options that can fit some truck owners better. So…
Is A Cat Back Exhaust Worth It?
Yes, a cat back exhaust system is worth it. If not for a seamless transition and what little modification you need to do, all things equal the sound of a cat back exhaust makes the mod well worth it. Just listen to the before and after comparison in this video:
So does a cat back exhaust make a difference? The biggest difference is the sound the cat back system makes. You will love turning over your truck each time. It takes a tame-sounding family truck and transforms it into a mean and aggressive sounding animal.
You will get better performance and higher MPG as well, though, to fully take advantage of the performance upgrades capable with a cat back exhaust you would need to upgrade additional parts as well. The whole really is greater than the sum of its parts.
Is A Cat Back Exhaust Illegal?
No! cat back systems are 100% legal in all 50 US states (yes including California). A cat back is used because the exhaust system is modified in the back of the catalytic converter.
The catalytic converter is an exhaust emission control device that reduces toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction (an oxidation and a reduction reaction). – Wikipedia
Since the catalytic converter is not affected there is no change to the emissions of your vehicle. Also, there are certain noise limits that would limit the use of certain exhaust systems, but if your cat back exhaust system is under 95 dB then you are well within the law.
That being said, a police officer can still issue you a ticket if they feel you are too loud. They do not have a decibel meter so if you are near the limit and the cop is having a bad day they may just give you a ticket, or even worse impound your car.
Will A Cat Back Exhaust Increase Horsepower?
A cat back exhaust system can offer a large increase in horsepower if the stock exhaust system restricts too much airflow. Opening up airflow can change the power band of your vehicle resulting in an increase in measurable horsepower.
Maybe a better question to ask is, “does a high flow cat increase HP?” Since you are changing the catalytic converter from stock to a “high flow” cat you can greatly increase horsepower. A high-flow cat paired with a cat back exhaust could dramatically increase horsepower across the entire powerband.
While you will gain horsepower, especially in the lower RPM power ranges, you won’t b polluting anymore. In fact, you may reduce emissions with a high-flow cat. This entirely depends on your driving style. And let’s face it you are not spending your hard-earned cash on expensive upgrades like these to drive Ms. Daisy. You will be going through tires and having a lot of fun doing it.
Does A Cat Back Exhaust Increase MPG?
Yes, a cat back exhaust system will increase MPG. Most exhaust systems will increase fuel efficiency and a full cat back exhaust can give you up to 10% fuel savings! You will pay off the cat back pretty quickly with savings like that.
The cat back exhaust system starts behind the stock catalytic converter and replaces the muffler as well. MPG will increase at least minimally depending on other upgrades and the make and model of your truck.
A cat back system has larger and more efficient tubes. This isn’t universally better but they in most instances offer a much more efficient exhaust removal process resulting in less energy wasted by your engine. This results in better performance and MPG.
With cat back exhaust systems ranging in price from a few hundred dollars all the way up to over $1,000, purchasing one may actually save you money in the long run with the fuel savings you will collect. Think about it…
Does A Cat Back Require A Tune?
No, a cat back exhaust system does not need a tune. It does not modify any part of the motor so it will not require any settings adjustment. It is installed after the catalytic converter and replaces the piping and the muffler. It is considered a “stage 1” type of modification. It is a simple bolt-on and independent mod that does not affect the drive train function.
Can You Pass Smog With Cat Back Exhaust System?
Yes, you can pass smog with a cat back exhaust. The catalytic converter is not adjusted, removed, nor changed in any way. A smog test checks the emissions exiting the muffler so the catalytic converter will provide enough filtration for your vehicle to successfully pass a smog test.
There is a visual portion of the smog check and if for any reason your cat back looks too homemade or damaged in any way the inspector may fail you based on a visual check. Not to mention, if there are any leaks in the cat back they can see, that would be an automatic failure.
Is Cat Back Better Than Axle Back Exhaust?
An axle back exhaust system may offer a more aggressive sound, a cheaper price, and an easier install. A cat back exhaust replaces more parts, so it has the opportunity for better performance and a more “subtle” engine sound if that is what is desired.
While a cat back exhaust system replaces everything “in back of” the catalytic converter, an axle back exhaust system replaces everything “in the back of” the rear axle. An axle back exhaust is sometimes called a “straight pipe” exhaust, or straight pipes.
It is a simple bolt-on system that may just replace the muffler with another or straight pass-through pipes. This open system will give your truck the most aggressive and loud rumble possible.
I had a Honda Civic and when I was replacing the exhaust manifold I drove it around the block with the exhaust manifold off. It was truly as open an exhaust system as you could get. Normally, you don’t hear the 2.0-liter DOHC engine.
But with no exhaust manifold, it sounded like a side by side! it really was throaty and beasty for a small 4 cylinder engine. Just imagine what a 5.7L Hemi in a Dodge RAM would sound like. Well actually, check out this video and find out!
In some states, you can have a truly open exhaust as they don’t require a catalytic converter. You can literally connect your exhaust manifold to the intermediate pipe, and mufflerless exhaust! Or a simpler option would be to install a “muffler delete” exhaust system. That is a fancy way of saying you took off your muffler.
Is Cat Back Louder Than An Axle Back Exhaust?
No, an axle back is louder than a cat back. It does differ from model to model but an axle back with straight pipes typically has less muffler insulation or no muffler at all. A cat back, even with larger a pipe diameter, will still muffle the sound compared to an axle back exhaust. This results in a loud AF engine.
What Is A Cat Back Delete?
A cat back delete doesn’t exist. When using the word “delete” you are stating you are removing that piece. A “cat back delete” would mean you are removing the cat back exhaust. So that means your exhaust system starts with the exhaust manifold, the catalytic converter, and… nothing.
This is obviously not practical. Though it is essentially a straight pipe exhaust, though the exhaust ends at the catalytic converter spewing exhaust down and out of your engine bay. This is an excellent way to collect exhaust residue in your engine bay. The minimum you would want is an intermediate or downpipe from the outlet of the catalytic converter pointing toward the street.
There, of course, is a cat back exhaust with a muffler delete. This is simply a cat back exhaust with the muffler or straight pipes going all the way to the exhaust tips. Or you can remove the catalytic converter and add a cat back exhaust.
What Is The Legal Sound Limit For An Exhaust?
There is no federal mandate for any vehicle noise limits. Certain states have noise limits, for example, in California, it is 95 dB. Other states have no limits. Though each state has certain laws that limit noise if something specific is not stated in the law. Cops have the ability to issue a fine or even worse, impound your car, at their discretion if they feel your car is operating in a dangerous manner.
So things like reckless driving, driving under the influence, a radio being too loud, or an exhaust being too loud are all fineable offenses if the issuing officer sees fit. Of course, they can be fought in court, and many times the case is thrown out. Just don’t run into a cop on a bad day and always be respectful. Kiss the ring and cops won’t come down hard on you.
Main Takeaways – Is A Cat Back Exhaust Worth It?
A cat back exhaust system is a great and exciting upgrade for your vehicle. The engine really comes alive and you will turn heads driving slow or hauling butt on the highway. It can turn a tame 4 cylinder into a beastly sleeper that won’t be too sleepy.
But is a cat back exhaust system worth it? It really depends on you and what you want out of your vehicle. For the sound, it is 100% worth it. For performance upgrades, you really have to study how a cat back versus an axle back or some type of delete option works for your individual vehicle. Then you can judge where a cat back exhaust is worth it.
These exhausts are worth it if you want to increase your car’s horsepower and speed. For example, the Magnaflow Cat Back Exhaust System for the 1997-2004 Chevy Silverado 1500 5.3L V8 can give up to 15% more power in stock form (or even better gains with tuning). If you’re looking for a quick way to get an instant boost in performance without breaking the bank, then this could be just what you need!
Do you have a cat back exhaust? If so, are the benefits worth it to you? Cat back exhausts look cool and sound great. They also can help give your car better performance, or at least that’s what people say.
But is the cost justifiable for these perks? Well, there are pros and cons to consider before making this investment in your vehicle. The article below will summarize speed gains from installing a cat back system on an engine as well as the costs of installation.
When considering whether or not to install one of these systems on your ride, take some time out to make sure everything lines up with your budget!
Thanks for reading and stay dirty