They sound awesome, but do aftermarket exhausts improve performance? The answer is yes, replacing some or all of the stock exhaust system can provide significant performance improvements and power gains.
I’ve worked with thousands of customers to unlock their 4×4’s potential, often utilising exhaust system upgrades as part of the process.
When customers ask “Does a new exhaust improve performance?”, I enjoy sharing the impact an exhaust upgrade can make.
If you’re considering an exhaust upgrade, here are some of the main benefits and considerations to keep in mind.
Quick Summary
- Stock exhausts focus on being cost-effective for manufacturers to make but they may be lacking in performance or quality
- Exhaust system upgrades can boost horsepower, improve overall performance, and create a stronger, more sporty sound
- Cat-back exhaust upgrades offer an ideal mix of performance gains and a sporty sound — all while being cost-effective
- Sound design, performance enhancements, vehicle make and model, and material quality are some of the factors that affect exhaust system upgrade cost
- Ensure all local regulations and guidelines are met when investing in an exhaust system upgrade
- It is illegal to remove or modify your vehicle’s DPF (diesel particulate filter) and can result in voided warranties, fines, and increased liability
- There are a variety of legal ways to enhance performance and efficiency without risking non-compliance
How Does an Exhaust Affect Performance?
Most vehicle manufacturers aim to maximise resources when installing parts in a vehicle. Of course, these parts will do the job. But vehicle owners often wonder, “Does a new exhaust improve performance?”.
There is absolutely room for improvement when it comes to upgrading stock exhaust systems. Stock exhausts often restrict sound, limit performance, and utilise cheap parts. Replacing some or all of the stock exhaust system can provide significant performance improvements and power gains.
So how do aftermarket exhausts improve performance? Here is a quick breakdown of the effects of an exhaust system on vehicle performance:
1. Muffler
The muffler reduces the noise created by the exhaust gases. If it malfunctions, a muffler can cause back pressure that decreases engine efficiency and reduces power output.
2. Exhaust Manifold
The exhaust manifold collects the exhaust gases from the engine’s cylinders and directs them into the exhaust system. A poorly properly designed or improperly sized exhaust manifold can reduce efficiency and restrict performance.
3. Catalytic Converter
The catalytic converter converts harmful pollutants into more neutral substances before they are released. By converting unburned hydrocarbons, nitrogen oxides, and carbon monoxide, fewer pollutants reach the atmosphere.
A malfunctioning catalytic converter can cause vehicle issues, including increased pressure and heat and problems with the exhaust manifold and pipes.
4. Exhaust Pipe Diameter
Exhaust pipe diameter directly influences engine performance. Cheap, thin exhaust pipes are more susceptible to cracks, dents, and damage. Thinner steel pipes also produce a tinny, higher-pitched exhaust note that many 4×4 owners dread.
Larger diameter exhaust pipes allow for better airflow. And better airflow means more horsepower, improved efficiency, and reduced back pressure.
Types of Exhaust Upgrades
Here’s a quick breakdown of the three main types of exhaust upgrades. Spoiler: The first one is my favourite.
Cat-Back Exhaust
- What Is It: A cat-back exhaust system replaces the catalytic converter to the muffler and everything in between.
- Benefits: Freer exhaust flow, enhanced performance, a more rumbling sound that resonates deeper, and improved fuel economy
- Who Is It Best For: If that deep, rumbling sound is what you’re after, the cat-back exhaust is hard to beat. They’re also the ideal blend of auditory boost with performance gains — all without going overboard on costs. I consider cat-back exhaust systems an all-around winner for the well-balanced benefits they provide.
Axle-Back Exhausts
- What It Is: Axle-back systems only replace parts from the rear axle to the backend of the car. This includes replacing the muffler.
- Benefits: Axle-back exhausts are more affordable than cat-back exhaust upgrades but still deliver a louder, sporty sound. However, they don’t offer the power gains that cat-back exhaust upgrades do.
- Who Is It Best For: Drivers looking for easier installation and a more affordable exhaust upgrade option may prefer axle-back exhausts. They’re a great way to achieve better acoustics without extensive costs or modifications.
Turbo-Back Exhausts
- What It Is: Turbo-back exhaust upgrades replace the entire factory exhaust system from the turbocharger outlet to the vehicle’s rear. Turbo-back exhaust systems enable a higher amount of gasses to exit the turbocharger. This boosts horsepower and efficiency to generate noticeable performance gains.
- Benefits: Enhanced exhaust flow, improved engine efficiency, significant power gains, improved handling, a sportier sound, and improved fuel efficiency
- Who Is It Best For: 4×4 enthusiasts looking for the highest performance gains.
Aftermarket Exhaust Benefits
Performance exhaust systems are designed to outperform stock parts in a variety of ways, resulting in the following benefits:
- Higher Horsepower: This is one of the common reasons for an exhaust upgrade. By increasing air intake and facilitating better airflow, exhaust upgrades can add significant torque and horsepower gains.
- Improved Fuel Economy: Performance exhaust systems optimise air levels and circulation in the engine. This decreased restriction makes it easier for the engine to clear exhaust gasses. This reduces the need for extra fuel consumption due to dirty air levels or poor circulation. I’ve talked to many drivers who were surprised at the increased fuel economy they noticed after an exhaust upgrade.
- Better Acoustics: Many 4×4 enthusiasts are after that deep, distinct rumbling sound. Exhaust upgrades can unlock a more aggressive sound that is tailored to what you are looking for.
- Improved Visual Appeal: Beyond enhanced performance and better fuel efficiency and acoustics, an exhaust upgrade can also elevate your 4×4’s style and give it a unique look.
Looking for more ways to optimise performance and increase power? Check out my guide on ECU remapping: What Is ECU Remapping?
How Much Does a Performance Exhaust Cost?
Our exhaust upgrades start from $1500, depending on your requirements. The exact cost will depend on a variety of factors, which I’ll cover next.
Factors Affecting the Cost
- Exhaust System Type: Custom and high-end systems cost more.
- Materials: Stainless steel is pricier but more durable and rust-resistant.
- Installation: Complexity and additional modifications (cutting/welding) increase costs.
- Performance Enhancements: Increased horsepower and optimized exhaust flow raise costs.
- Sound Design: Custom exhaust notes add to the price.
- Vehicle Make & Model: Unique or high-end models cost more.
- Part Costs: High-efficiency catalytic converters and oxygen sensors ($20–$100) add expenses.
Things to Consider Before You Upgrade
Before an exhaust system upgrade, it’s important to make an informed decision. I’ve had many 4×4 owners come in looking for help after a disappointing attempt at DIY exhaust upgrades. Many people jump into buying a cheap exhaust upgrade system that improves exhaust notes but fails to address quality and performance.
Here are factors to consider to ensure a successful upgrade that meets your needs.
- Warranty: This is the biggest factor I tell clients to research before moving forward with an exhaust upgrade. Double-check if and how the modifications will impact your vehicle’s warranty covers.
- Vehicle Compatibility: Make sure the exhaust upgrade will be compatible with your 4×4’s model, make, and year.
- Performance Goals: Determine your priorities for performance goals. Is a better sound the most important? Or is increased torque and horsepower your main priority?
- Understand Crush Vs. Mandrel Bent Exhaust Tubing: Exhaust tubing can be either crush bent or mandrel bent. Crush bent is cheaper but restricts performance. I also find crush bent exhaust quite awful in terms of visual appeal. Mandrel Bent exhaust tubing is the clear winner, with a premium appearance, maximum exhaust flow, and high accuracy.
- Exhaust Pipe Quality and Thickness: A thick-walled exhaust pipe can handle the rigors of off-road terrain better, leading to performance gains and smoother handling. However, I recommend finding the right balance. An oversized exhaust pipe can negatively impact other aspects, such as torque, fuel efficiency, and power. I find that ensuring the diameter is proportional to the vehicle’s engine capacity is usually the right balance.
- Exhaust Mufflers and Resonators: Adding an aftermarket exhaust with a resonator can help unleash the true sound potential of your engine. If you have a cat-back or pre-DPF vehicle, you may want to add a muffler to prevent annoying cabin drone during long-distance trips or towing.
- Heat Reduction: Excessive exhaust gas temperatures (EGTs) can cause damage to pistons, cylinder heads, exhaust valves, and the manifold. An unrestricted manifold bent pipe can move gasses through the system as quickly and efficiently as possible. This lowers EGTs to protect the exhaust manifold and engine from excessive heat.
- Legal Compliance: It is imperative to make sure any exhaust upgrades comply with emission standards and local regulations. If you run a pre-DPF/ turbo back exhaust, your 4×4 is legally required to have a catalytic converter.
If you’re looking for performance gains, I’d suggest a cat-back exhaust for a compliant horsepower boost. Cat-back exhaust upgrades are generally legal in Australia, given they comply with emission and noise regulations.
Modern diesels run a DPF (diesel particulate filter) to reduce emissions. Unfortunately, DPFs are known for reducing performance as well. However, it is illegal to remove or modify your DPF. Deleting the DPF makes your 4×4 un-roadworthy, meaning you’ll be accountable in the event of an accident. Your insurance will also be voided and you’ll need to reinstall the DPF should you decide to sell your 4×4.
I always recommend keeping your exhaust system legal to avoid legal implications, warranty issues, and fines. The good news is that we have a variety of ways to enhance performance without risking non-compliance.
You May Also Like: Do DPF Filters Need Replacing?
Unleash Your 4×4’s Full Potential with an Exhaust System Upgrade
I hope these points are helpful in understanding why the answer to, “Does a bigger exhaust improve performance?” is a yes.
If you want more horsepower, better fuel efficiency, or a more pronounced exhaust note, a performance exhaust upgrade can be a great option.
We can cater an exhaust system upgrade to your budget, needs, and goals to unleash your 4×4’s full performance potential.
Contact our team of modification specialists to get a quote for your 4×4 exhaust system upgrade in Perth. We’ll determine the ideal type of exhaust system upgrade to suit your 4×4’s make and model, along with your performance goals.
