When you first buy your new car, an aftermarket exhaust is probably the first thing on your mind. Whether it be that your OEM exhausts is too quiet, or you’re looking for more power, exhaust headers is an excellent first upgrade for your car.
What are exhaust headers?
Exhaust headers are the most important part of your exhaust setup. To understand how exhaust headers work, you must first understand how a car engine works.
In the most simplistic form, a car engine works by burning gasoline in the cylinder, and pistons pushes the exhausts gas out. If the exhaust gas cannot be fully pushed out, it will cause back pressure to the engine and thus losing horsepower.
The purpose of upgrading to aftermarket headers is to reduce back pressure and allow for exhaust gas to smoothly flow out of the car, thus allowing for increased horsepower and torque.
Equal Length vs. Unequal Length
This decision is mostly for Subaru owners. Unequal length headers (UEL for short), are headers known of the famous Subie Rumble. See video below:
VIDEO BY: 86 Speed
The key difference between UEL and EL headers is the length of the exhaust piping. UEL headers as the name states is unequal in length where 1 side is longer than the other whereas equal length headers have the same exhaust length on both sides.
Difference shown below:
Though in my opinion the UEL headers sound way better, if you’re purely track focused, EL headers do perform marginally better than UEL headers. For those who own a 86/BRZ/FRS, I would highly recommend giving this a read: UEL vs EL Headers: Which is better for your 86/FRS/BRZ that goes through the benefits of EL vs. UEL in more detail.
Long Tube vs. Short Tube
In pure design aspects, the difference between the long tube and short tube is as its name states, the length of the exhaust port pipes. Long tube = longer, short tube = shorter.
Long tube headers result in lower exhaust pressure and provide a ton of power in the mid to high RPM ranges. This header is best for high revving cars such as the S2K and track cars. The downside is that it’s more difficult to install because it requires for more room in the engine bay.
Short tube headers are best in the mid RPM range. This header is best for daily cars where you’re not constantly redlining the car. It’s great to have a little boost when you’re trying to pass someone without the car screaming at them on the backside.
There are 2 critical pipe sizing on your headers: Primary diameter and Secondary diameter.
Primary diameter is the size of the piping of your exhaust port pipes. Getting this right is the most important factor of the design of the headers, but this decision is usually left by the aftermarket exhaust manufacturer and not the consumer. So, for the most part, you don’t have to worry about this.
Secondary diameter is the size of the piping of which it attaches to the rest of your exhausts. The wider the diameter, the less restrictive your exhaust and more power it will produce. The only down side is that with a larger diameter, your exhaust will also be substantially louder.
If you’re from the aftermarket scene, you probably heard of people going catless. This means removing catalytic converters from the car, which improves exhaust flow at the cost of some legal standards.
A catalytic converter is an exhaust emission control device by reducing the amount of toxic gasses and pollutants in exhaust gas being released back out into the environment. The catalytic converter also stops the exhaust from smelling like burning gasoline.
Wherever you live, it is most likely that if you remove the catalytic converter, it is against your states law. If you do get pulled over, you might be able to pass a visual, but it’s uncertain if you’ll pass a sniff test. So for a few HPs, it’s up to you if it’s worth removing the cat.
As another note, if you remove the catalytic converter, your CEL light will come on and will require a tune to remove the error code