Exhaust systems are often the first item on the list for vehicle owners to modify or replace when seeking performance gains and an improvement in sound quality (something louder and sportier).
While horsepower gains may be limited on naturally-aspirated cars with a muffler swap, for turbocharged cars changing the muffler or entire system is a no-brainer for unleashing more power from that forced-induction engine.
Today, we will outline why you should consider a performance muffler and cover some basic information about muffler design.
We’ve also listed five options we think would be suitable for installation on anything from a Golf GTI or a Commodore SS, and what benefits they offer to potential buyers.
MagnaFlow 10415 Exhaust Muffler
One of the leading names in exhausts, Magnaflow has been around since 1981. The 10415 stainless-steel muffler is a straight-through design with stainless steel mesh-wrapped packing. While you will definitely get more noise from the Magnaflow, exhaust drone is low (which is important if you drive for hours on end) and the sound is throaty and deep, in keeping with most sports cars. The Magnaflow 10415 represents the best all-round value here.
Thrush 17651 Welded Muffler
For over 50 years Thrush has been supporting the American hot rodding scene, so it is only natural there is Australian overlap for the Ford and Holden crew. The 17651 two-chamber muffler is known for good value and making a great sound while not being overly loud. Available in 2.25″, 2.5″, and 3″ inlet/outlet pipe dimensions, it is one of the best for 6-cylinder and V8 vehicles.
Flowmaster 40 Series Original Muffler
The 40 Series from Flowmaster was designed to be one of their most aggressive-sounding range of mufflers. Another chambered design with the high quality Flowmaster’s parent company Holley is famous for, this muffler is a great option if performance and durability are priorities.
Dynomax Race Bullet Muffler
With stainless steel construction and fibreglass packing, the lightweight 24215 Race Bullet muffler from Dynomax is a compact model making for easy installation on most vehicles and the best muffler for a race car. Its high-flow design and small size means it will be loud, though that will also maximise horsepower by minimising back pressure. The bargain of this collection here.
Borla 40359 ProXS Muffler
The straight-through perforated and insulated ProXS series of mufflers from American brand Borla are a no-nonsense, reversible design that gives flexibility for installation on nearly any vehicle. Stainless steel, oval-shaped for better clearance, their “Million-Mile warranty” is an indication of excellent build quality. Various inlet and outlet pipe placements are available so it should be a cinch to fit under any car.
Universal Muffler Buying Guide
Still unsure which muffler is right for your wheels? Below we cover some of the key reasons to upgrade your muffler, along with the main types and materials. We’ve also included an FAQ section to answer common muffler-related questions.
Pros and cons of a performance exhaust system
Performance
Exhaust systems restrict an engine’s ability to breathe efficiently, and the more restrictive a system with its pipe diameter and the potentially bad cost-limited design of its muffler, the more horsepower that is lost.
It is pretty simple; flow more gas, make more power, so your free-flowing exhaust system is going to liberate more power, especially on a turbo engine. If exotic and expensive materials like titanium are used, the lower weight is a nice benefit as well.
Sound
A muffler is designed to do exactly that; muffle engine noise, ensuring road trips and the daily commute are a peaceful drive. Not everyone appreciates that, so an exhaust note that would otherwise be too loud or aggressive for some will be perfect for others.
Manufacturers spend millions of dollars and invest thousands of hours tuning the sound of their cars, so getting the right sound is difficult, to say the least.
Turbo engines have the characteristic of being very quiet when compared to the loud naturally-aspirated versions before exhausts are taken into account.
Quality
When manufacturers set out to build a car, the cost of each part has to be rationalised to make sure the final price of the vehicle doesn’t blow out of control.
Unfortunately, this means that on many cars, as long as parts survive the warranty period, that’s enough. However, an aftermarket exhaust should be made from high quality materials like stainless steel or even titanium, so rust will be a distant memory.
Exhaust parts can also be custom-designed to better protect them from damage, useful in the case of off-roading 4x4s.
Fuel economy
The back pressure of an exhaust system has a direct impact on the efficiency of an engine, and the greater the exhaust gas flow’s restriction, the higher the fuel consumption. Performance mufflers and systems seek to reduce the amount of back pressure, which in turn improves fuel economy. Less fuel and more power is a definite win-win.
Aesthetics
Seeing as performance cars are normally their owner’s pride and joy, how it looks is normally a factor.
While it must be said the exhaust tips won’t add anything in terms of performance or sound, a car that looked a little meek before can be made to look much more aggressive with a tip that is bigger or more aggressive in style (slash-cut, polished, and so on).
Types of mufflers
Straight-through muffler
Simple construction, the muffler will be a straight-piece of perforated pipe filled with noise-insulating packing. These are simply-designed, easy to install, and often the louder option.
Chambered
A chambered muffler is full of baffles which turns a big open space into smaller, more complex ones to separate and disturb the sound waves of the exhaust gases. These redirected sound waves will cancel each other out, thus reducing but also altering the sound.
Chambered is normally quieter than a straight-through muffler, the scavenging effect created by the baffles means the exhaust gases will leave the muffler faster than they entered, limiting the amount of horsepower lost.
Turbo muffler
While looking a lot like a chambered muffler from the outside, internally they are quite different. Perforated pipes are fashioned into an S-shape within the muffler, and some designs have noise-absorbing fibreglass packing as well.
These are normally quieter than both chambered and straight-through mufflers as the gases have to travel further through all that extra pipe.
Muffler and exhaust construction materials
Mild steel
Mufflers at the low-end of the price range will normally be made from low-quality mild steel. Prone to corrosion if the rust-protection coating is damaged, they can expect to crack at joins and welds over both years and heat cycles. Internal exhaust condensation from cars that spend long periods of time not being driven also speeds up this rusting process.
Stainless steel
Manufacturers of higher-end cars will use stainless steel for their exhaust systems, for its superior corrosion resistance and strength (as well as better marketing clout). The difference from mild steel is the addition of chromium, which also gives that characteristic shiny finish. It is ideal for 4x4s as it can also handle impacts better than mild steel. Stainless Steel is also used on most performance cars in lieu of more exotic materials.
Titanium
One of the ultimate materials for exhausts and mufflers, titanium is extremely light and used in high-performance applications by manufacturers like BMW, McLaren, and even Ford with its GT supercar. That dramatic weight saving over a stainless steel system comes at a very high cost, though.
Inconel
A “superalloy” made largely from nickel and chromium, Formula 1 teams have used it for their exhausts for years now. Incredibly light, incredibly heat resistant, incredibly expensive. Some bespoke items for small manufacturers like Singer are also made from Inconel, though performance and looks are priorities far beyond any cost consideration.
Carbon Fibre
Mainly reserved for the use of mufflers on sports bikes, carbon fibre has become more popular as the price of manufacturing it has come down over the years. Lighter than most alloys and a better heat insulator as well, but very difficult to repair properly if damaged, which is not difficult to do thanks to its brittleness. Carbon fibre use on cars is mainly aesthetic (the exhaust tips), but not exclusively.
Muffler FAQ
What type of muffler gives the deepest sound?
A chambered muffler generally gives a deeper sound than a straight-through muffler as its design cancels out certain sound waves, so careful design can ensure the result is something pleasing to the ear. Additionally, the various chambers in the muffler effectively act to lengthen the overall exhaust by forcing the sound waves to travel further, in the same way a tuba has a deeper sound than a trumpet.
What is the best sounding muffler for a 4 cylinder?
4 cylinder engines are normally going to sound higher-pitched than a big 6 cylinder or a V8. Eliminating those higher frequency sound waves with a chambered muffler will give some much sought-after bass and aggression.
Which is louder Flowmaster 40 or 44?
It is generally accepted the classic 40-series from Flowmaster is the loud option compared to the Super 44, but the Super 44 has a deeper sound that may suit the tastes of more people. However, Flowmaster also produce a Super-40 series which are dimensionally identical to the original 40-series, but makes a sound that they say is deeper and richer.
How do I choose the right muffler?
It is important to know what you want when changing the muffler on your vehicle, and the trade-offs that come with any benefits. The best muffler may be one that is not too loud or drony if you do a lot of highway driving, so that might mean sacrificing some potential performance gains. A high-flow muffler with a sporty sound might be just fine if you drive the car on weekends. Get as much information as possible from professionals and, even better, see if your exhaust or performance shop can fit different options to demonstrate how different each muffler will sound. Each car and engine combination makes knowing how every muffler will sound exactly very difficult, so the key is to listen to as many options as possible.
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