Turning your Hilux into an off-road beast has never been easier. With so many different modifications and accessories available today, you have a wide range to choose from and modify your Hilux any way you see fit. One of the most popular aftermarket modifications are performance Hilux exhaust systems. The exhaust system is one of the parts that can unlock most of your engine’s potential. Stock exhaust systems are made with restrictions, as a result of cheaper fabrication processes and the use of inferior materials. This is not done intentionally, but to reduce the overall cost of the vehicle in order to make its price tag more competitive. 

Having said that, if you want to free your Hilux of these restrictions, you’re probably considering an aftermarket exhaust. Not sold on the idea? Here are all the ways aftermarket Hilux exhaust systems will improve performance and fuel economy.

Superior Materials

As aforementioned, stock exhaust systems are typically made of inferior-quality materials, such as mild steel. While mild steel is good enough for the average driver, off-roaders and those looking to squeeze the most power and mileage out of their vehicles need something more. That being said, aftermarket exhaust systems are made of quality-grade stainless or aluminised steel.

Aluminised steel exhausts are lightweight, yet durable and resistant to corrosion and rust. As a result, you get better fuel efficiency and a lower overall GVM. Stainless steel exhausts, on the other hand, are heavier, but they’re extremely durable. Most manufacturers place a lifetime guarantee on their stainless steel exhausts. There are different grades of stainless steel, such as T409 and T304. The difference between them is the amount of chromium and nickel present. 

Superior Bending Techniques

Stock exhaust systems are manufactured using wrinkled or crush bending. These bending techniques are economical and simpler, making them the go-to choice for most vehicle manufacturers. They involve using a radius die and backing shoes, without a supporting mandrel. As a result, you get a functional, but depressed bend that restricts airflow. 

On the other hand, mandrel bending makes for far smoother bends, and virtually uninterrupted exhaust pipes that are free of creases and kinks. This is the result of the mandrel that’s being implemented inside the pipe as it’s sent through the die and shoe. The mandrel supports the walls, resulting in bends free of any diameter changes. The mandrel is generally lubricated using lithium grease to provide smoother gliding action. However, just because a mandrel supports the inside of the pipe, it doesn’t mean that it won’t experience slight deformities inside the bend.

The mandrels are made up of a series of rounded radius-faced balls secured together using a flexible cable. The balls are generally made of brass and can flex and follow the bend radius, supporting the pipe’s interior walls throughout the entire bending process. The number of balls and their width will have an impact on the final appearance of the pipes. 

Larger Diameter Pipes

Aftermarket exhaust systems typically come with pipes that are considerably larger in diameter. As a result, you get improved airflow of clean, cool air inside the engine, and emissions leave the system faster. Think of aftermarket exhaust systems as a 4-lane highway, whereas stock exhausts only have 2 lanes. Traffic will be much smoother on 4 lanes during peak hours.

However, larger diameter pipes aren’t better by default. If the pipes are too big for your engine, you might get a negative impact instead. For instance, V-8 engines will generally require pipes of 2.5- to 3.5-inches. If the pipes are larger, you’ll lose one exhaust velocity and your low- and mid-range power will suffer in the process. The diameter of pipes always refers to the pipe’s outer diameter. That being said, expect the inner diameter to be always slightly smaller.

Pipe Shape

Although the majority of the pipes are round, they don’t have to be. There are specialty dies that allow for the creation of oval pipes. But why should you even consider oval pipes? Well, firstly, oval-shaped pipes are useful when you have clearance issues. Oval pipes can have the same cross-section volume as round pipes, but they’re narrower on the plane, providing extra ground clearance on vehicles with low ground clearance. This allows the same amount of flow, while ensuring a more compact installation. 

Conclusion

Aftermarket Hilux exhaust systems are the best money-for-value upgrade you can make on your Hilux. It provides a tonne of benefits, and is relatively straightforward to install. While most people aren’t too keen on installing aftermarket exhaust themselves, it’s certainly something a skilful handyman can do on a Sunday afternoon. Aftermarket exhausts are made using superior materials, and feature superior bends, as well as larger diameter pipes, all of which allow for better airflow of the exhaust gases. As a result, you get a considerable improvement in performance, and fuel saving benefits.